gd 1.8.4
A graphics library for fast image creation
Follow this link to the latest version of this document.
_HEY! READ THIS!_ gd 1.8.4 creates PNG, JPEG and WBMP images, not
GIF images. This is a good thing. PNG is a more compact format, and
full compression is available. JPEG works well with photographic
images, and is still more compatible with the major Web browsers
than even PNG is. WBMP is intended for wireless devices (not
regular web browsers). Existing code will need modification to call
gdImagePng or gdImageJpeg instead of gdImageGif. _Please do not ask
us to send you the old GIF version of GD._ Unisys holds a patent on
the LZW compression algorithm, which is used in fully compressed
GIF images. The best solution is to move to legally unencumbered,
well-compressed, modern image formats such as PNG and JPEG as soon
as possible.
gd 1.8.4 _requires_ that the following libraries also be installed:
libpng (see the libpng home page)
zlib (see the info-zip home page) zlib
jpeg-6b or later, if desired (see the Independent JPEG Group home
page)
If you want to use the TrueType font support, you must also install
the _FreeType 2.x library_, including the header files. See the
Freetype Home Page, or SourceForge. No, I cannot explain why that
site is down on a particular day, and no, I can't send you a copy.
If you want to use the Xpm color bitmap loading support, you must
also have the X Window System and the Xpm library installed (Xpm is
often included in modern X distributions).
Please read the documentation and install the required libraries.
Do not send email asking why png.h is not found. See the
requirements section for more information. Thank you!
Table of Contents
* Credits and license terms
* What's new in version "XYZ" of GD?
* What is gd?
* What if I want to use another programming language?
* What else do I need to use gd?
* How do I get gd?
* How do I build gd?
* gd basics: using gd in your program
* webpng: a useful example
* Function and type reference by category
* About the additional .gd image file format
* Please tell us you're using gd!
* If you have problems
* Alphabetical quick index
Up to the Boutell.Com, Inc. Home Page
Credits and license terms
In order to resolve any possible confusion regarding the authorship of
gd, the following copyright statement covers all of the authors who
have required such a statement. _If you are aware of any oversights in
this copyright notice, please contact Thomas Boutell who will be
pleased to correct them._
COPYRIGHT STATEMENT FOLLOWS THIS LINE
Portions copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000 by Cold
Spring Harbor Laboratory. Funded under Grant P41-RR02188 by the
National Institutes of Health.
Portions copyright 1996, 1997, 1998, 1999, 2000 by Boutell.Com,
Inc.
Portions relating to GD2 format copyright 1999, 2000 Philip Warner.
Portions relating to PNG copyright 1999, 2000 Greg Roelofs.
Portions relating to libttf copyright 1999, 2000 John Ellson
(ellson@lucent.com).
Portions relating to JPEG copyright 2000, Doug Becker and copyright
(C) 1994-1998, Thomas G. Lane. This software is based in part on
the work of the Independent JPEG Group.
Portions relating to WBMP copyright 2000 Maurice Szmurlo and Johan
Van den Brande.
_Permission has been granted to copy, distribute and modify gd in
any context without fee, including a commercial application,
provided that this notice is present in user-accessible supporting
documentation._
This does not affect your ownership of the derived work itself, and
the intent is to assure proper credit for the authors of gd, not to
interfere with your productive use of gd. If you have questions,
ask. "Derived works" includes all programs that utilize the
library. Credit must be given in user-accessible documentation.
_This software is provided "AS IS."_ The copyright holders disclaim
all warranties, either express or implied, including but not
limited to implied warranties of merchantability and fitness for a
particular purpose, with respect to this code and accompanying
documentation.
Although their code does not appear in gd 1.8.4, the authors wish
to thank David Koblas, David Rowley, and Hutchison Avenue Software
Corporation for their prior contributions.
END OF COPYRIGHT STATEMENT
What is gd?
gd is a graphics library. It allows your code to quickly draw images
complete with lines, arcs, text, multiple colors, cut and paste from
other images, and flood fills, and write out the result as a PNG or
JPEG file. This is particularly useful in World Wide Web applications,
where PNG and JPEG are two of the formats accepted for inline images
by most browsers.
gd is not a paint program. If you are looking for a paint program, you
are looking in the wrong place. If you are not a programmer, you are
looking in the wrong place.
gd does not provide for every possible desirable graphics operation.
It is not necessary or desirable for gd to become a kitchen-sink
graphics package, but version 1.7.3 incorporates most of the commonly
requested features for an 8-bit 2D package. Support for truecolor
images, including truecolor JPEG and PNG, is planned for version 2.0.
What if I want to use another programming language?
Perl
gd can also be used from Perl, courtesy of Lincoln Stein's GD.pm
library, which uses gd as the basis for a set of Perl 5.x classes.
Highly recommended.
Tcl
gd can be used from Tcl with John Ellson's Gdtclft dynamically loaded
extension package. (Gdtclft2.0 or later is needed for gd-1.6 and up
with PNG output.)
Pascal
Pascal enthusiasts should look into Michael Bradbury's gdfp package.
Haskell
A new gd interface is now available for Haskell programmers.
REXX
A gd interface for the REXX language is available.
Any Language
There are, at the moment, at least three simple interpreters that
perform gd operations. You can output the desired commands to a simple
text file from whatever scripting language you prefer to use, then
invoke the interpreter.
* tgd, by Bradley K. Sherman
* fly, by Martin Gleeson
What's new in version 1.8.4?
* Add support for FreeType2 (John Ellson ellson@lucent.com)
* Add support for finding in fonts in a builtin DEFAULT_FONTPATH, or
in a path from the GDFONTPATH environment variable.
* remove some unused symbols to reduce compiler warnings
* bugfix in size comparisons in gdImageCompare
* REXX now mentioned
* All memory allocation functions are now wrapped within the
library; gdFree is exported and recommended for freeing memory
returned by the gdImage(Something)Ptr family of functions.
What's new in version 1.8.3?
* WBMP output memory leak fixed
* #include <gd.h> corrected to #include "gd.h" in gd_wbmp.c
* Documented the fact that the source and output images shouldn't
match in the WBMP test except for black and white source images
What's new in version 1.8.2?
* WBMP support debugged and improved by Johann Van den Brande
* WBMP tests added to gdtest.c by Thomas Boutell
* Use of platform-dependent 'install' command removed by Thomas
Boutell
* Comments added to Makefile warning users to juggle the order of
the libraries if the linker complains; is there any portable way
to do this automatically, short of using autoconf?
* Documentation of gdImageCreateFromXpm corrected
* Updated links to fast-moving, always dodging libpng and zlib web
sites
What's new in version 1.8.1?
* Optional components no longer built by default (following the
documentation)
* JPEG code no longer requires inappropriate header files
* Win32 patches from Joe Gregorio
* 16-bit font support for bdftogd, from Honza Pazdziora
What's new in version 1.8?
* Support for JPEG output, courtesy of Doug Becker
* A link to Michael Bradbery's Pascal wrapper
* Support for WBMP output, courtesy of Maurice Szmurlo
* gdImageColorClosestHWB function based on hue, whiteness,
blackness, superior to the regular gdImageColorClosest function,
courtesy of Philip Warner
* License clarification: yes, you can modify gd
Additional JPEG Information
Support for reading and writing JPEG-format images is courtesy of Doug
Becker and the Independent JPEG Group / Thomas G. Lane. You can get
the latest version of the IJG JPEG software from
ftp://ftp.uu.net/graphics/jpeg/ (e.g., the jpegsrc.v6b.tar.gz file).
You _must_ use version 6b or later of the IJG JPEG software. You might
also consult the JPEG FAQ at http://www.faqs.org/faqs/jpeg-faq/.
What's new in version 1.7.3?
Another attempt at Makefile fixes to permit linking with all libraries
required on platforms with order- dependent linkers. Perhaps it will
work this time.
What's new in version 1.7.2?
An uninitialized-pointer bug in gdtestttf.c was corrected. This bug
caused crashes at the end of each call to gdImageStringTTF on some
platforms. Thanks to Wolfgang Haefelinger.
Documentation fixes. Thanks to Dohn Arms.
Makefile fixes to permit linking with all libraries required on
platforms with order- dependent linkers.
What's new in version 1.7.1?
A minor buglet in the Makefile was corrected, as well as an inaccurate
error message in gdtestttf.c. Thanks to Masahito Yamaga.
What's new in version 1.7?
Version 1.7 contains the following changes:
* Japanese language support for the TrueType functions. Thanks to
Masahito Yamaga.
* autoconf and configure have been removed, in favor of a carefully
designed Makefile which produces and properly installs the library
and the binaries. System-dependent variables are at the top of the
Makefile for easy modification. I'm sorry, folks, but autoconf
generated _many, many confused email messages_ from people who
didn't have things where autoconf expected to find them. I am not
an autoconf/automake wizard, and gd is a simple, very compact
library which does not need to be a shared library. I _did_ make
many improvements over the old gd 1.3 Makefile, which were
directly inspired by the autoconf version found in the 1.6 series
(thanks to John Ellson).
* Completely ANSI C compliant, according to the -pedantic-errors
flag of gcc. Several pieces of not-quite-ANSI-C code were causing
problems for those with non-gcc compilers.
* gdttf.c patched to allow the use of Windows symbol fonts, when
present (thanks to Joseph Peppin).
* extern "C" wrappers added to gd.h and the font header files for
the convenience of C++ programmers. bdftogd was also modified to
automatically insert these wrappers into future font header files.
Thanks to John Lindal.
* Compiles correctly on platforms that don't define SEEK_SET. Thanks
to Robert Bonomi.
* Loads Xpm images via the gdImageCreateFromXpm function, if the Xpm
library is available. Thanks to Caolan McNamara.
What's new in version 1.6.3?
Version 1.6.3 corrects a memory leak in gd_png.c. This leak caused a
significant amount of memory to be allocated and not freed when
writing a PNG image.
What's new in version 1.6.2?
Version 1.6.2 from John Ellson adds two new functions:
* gdImageStringTTF - scalable, rotatable, anti-aliased, TrueType
strings using the FreeType library, but only if libttf is found by
configure. _We do not provide TrueType fonts. Obtaining them is
entirely up to you._
* gdImageColorResolve - an efficient alternative for the common code
fragment:
if ((color=gdImageColorExact(im,R,G,B)) < 0)
if ((color=gdImageColorAllocate(im,R,G,B)) < 0)
color=gdImageColorClosest(im,R,G,B);
Also in this release the build process has been converted to GNU
autoconf/automake/libtool conventions so that both (or either) static
and shared libraries can be built.
What's new in version 1.6.1?
Version 1.6.1 incorporates superior PNG reading and writing code from
Greg Roelofs, with minor modifications by Tom Boutell. Specifically, I
altered his code to read non-palette images (converting them to
palette images badly, by dithering them), and to tolerate palette
images with types of transparency that gd doesn't actually support (it
just ignores the advanced transparency features). Any bugs in this
area are therefore my fault, not Greg's.
Unlike gd 1.6, users should have no trouble linking with gd 1.6.1 if
they follow the instructions and install all of the pieces. However,
_If you get undefined symbol errors, be sure to check for older
versions of libpng in your library directories!_
What's new in version 1.6?
Version 1.6 features the following changes:
_Support for 8-bit palette PNG images has been added. Support for GIF
has been removed._ This step was taken to completely avoid the legal
controversy regarding the LZW compression algorithm used in GIF.
Unisys holds a patent which is relevant to LZW compression. PNG is a
superior image format in any case. Now that PNG is supported by both
Microsoft Internet Explorer and Netscape (in their recent releases),
we highly recommend that GD users upgrade in order to get
well-compressed images in a format which is legally unemcumbered.
What's new in version 1.5?
Version 1.5 featured the following changes:
_New GD2 format_
An improvement over the GD format, the GD2 format uses the zlib
compression library to compress the image in chunks. This
results in file sizes comparable to GIFs, with the ability to
access parts of large images without having to read the entire
image into memory.
This format also supports version numbers and rudimentary
validity checks, so it should be more 'supportable' than the
previous GD format.
_Re-arranged source files_
gd.c has been broken into constituant parts: io, gif, gd, gd2
and graphics functions are now in separate files.
_Extended I/O capabilities._
The source/sink feature has been extended to support GD2 file
formats (which require seek/tell functions), and to allow more
general non-file I/O.
_Better support for Lincoln Stein's Perl Module_
The new gdImage*Ptr function returns the chosen format stored
in a block of memory. This can be directly used by the GD perl
module.
_Added functions_
gdImageCreateFromGd2Part - allows retrieval of part of an image
(good for huge images, like maps),
gdImagePaletteCopy - Copies a palette from one image to
another, doing it's best to match the colors in the target
image to the colors in the source palette.
gdImageGd2, gdImageCreateFromGd2 - Support for new format
gdImageCopyMerge - Merges two images (useful to highlight part
of an image)
gdImageCopyMergeGray - Similar to gdImageCopyMerge, but tries
to preserve source image hue.
gdImagePngPtr, gdImageJpegPtr, gdImageWBMPPtr, gdImageGdPtr,
gdImageGd2Ptr - return memory blocks for each type of image.
gdImageCreateFromPngCtx, gdImageCreateFromGdCtx,
gdImageCreateFromGd2Ctx, gdImageCreateFromGd2PartCtx - Support
for new I/O context.
_NOTE:_ In fairness to Thomas Boutell, any bug/problems with any of
the above features should probably be reported to Philip Warner.
What's new in version 1.4?
Version 1.4 features the following changes:
Fixed polygon fill routine (again)
Thanks to Kirsten Schulz, version 1.4 is able to fill numerous
types of polygons that caused problems with previous releases,
including version 1.3.
Support for alternate data sources
Programmers who wish to load a GIF from something other than a
stdio FILE * stream can use the new gdImageCreateFromPngSource
function.
Support for alternate data destinations
Programmers who wish to write a GIF to something other than a
stdio FILE * stream can use the new gdImagePngToSink function.
More tolerant when reading GIFs
Version 1.4 does not crash when reading certain animated GIFs,
although it still only reads the first frame. Version 1.4 also
has overflow testing code to prevent crashes when reading
damaged GIFs.
What's new in version 1.3?
Version 1.3 features the following changes:
Non-LZW-based GIF compression code
Version 1.3 contained GIF compression code that uses simple Run
Length Encoding instead of LZW compression, while still
retaining compatibility with normal LZW-based GIF decoders
(your browser will still like your GIFs). _LZW compression is
patented by Unisys. We are currently reevaluating the approach
taken by gd 1.3. The current release of gd does not support
this approach. We recommend that you use the current release,
and generate PNG images._ Thanks to Hutchison Avenue Software
Corporation for contributing the RLE GIF code.
8-bit fonts, and 8-bit font support
This improves support for European languages. Thanks are due to
Honza Pazdziora and also to Jan Pazdziora . Also see the
provided bdftogd Perl script if you wish to convert fixed-width
X11 fonts to gd fonts.
16-bit font support (no fonts provided)
Although no such fonts are provided in the distribution, fonts
containing more than 256 characters should work if the
gdImageString16 and gdImageStringUp16 routines are used.
Improvements to the "webpng" example/utility
The "webpng" utility is now a slightly more useful application.
Thanks to Brian Dowling for this code.
Corrections to the color resolution field of GIF output
Thanks to Bruno Aureli.
Fixed polygon fills
A one-line patch for the infamous polygon fill bug, courtesy of
Jim Mason. I believe this fix is sufficient. However, if you
find a situation where polygon fills still fail to behave
properly, please send code that demonstrates the problem, _and_
a fix if you have one. Verifying the fix is important.
Row-major, not column-major
Internally, gd now represents the array of pixels as an array
of rows of pixels, rather than an array of columns of pixels.
This improves the performance of compression and decompression
routines slightly, because horizontally adjacent pixels are now
next to each other in memory. _This should not affect properly
written gd applications, but applications that directly
manipulate the pixels array will require changes._
What else do I need to use gd?
To use gd, you will need an ANSI C compiler. _All popular Windows 95
and NT C compilers are ANSI C compliant._ Any full-ANSI-standard C
compiler should be adequate. _The cc compiler released with SunOS
4.1.3 is not an ANSI C compiler. Most Unix users who do not already
have gcc should get it. gcc is free, ANSI compliant and a de facto
industry standard. Ask your ISP why it is missing._
As of version 1.6, you also need the zlib compression library, and the
libpng library. As of version 1.6.2, you can draw text using
antialiased TrueType fonts if you also have the libttf library
installed, but this is not mandatory. zlib is available for a variety
of platforms from the zlib web site. libpng is available for a variety
of platforms from the PNG web site.
You will also want a PNG viewer, if you do not already have one for
your system, since you will need a good way to check the results of
your work. Netscape 4.04 and higher, and Microsoft Internet Explorer
4.0 or higher, both support PNG. For some purposes you might be
happier with a package like Lview Pro for Windows or xv for X. There
are PNG viewers available for every graphics-capable modern operating
system, so consult newsgroups relevant to your particular system.
How do I get gd?
By HTTP
* Gzipped Tar File (Unix)
* .ZIP File (Windows)
By FTP
* Gzipped Tar File (Unix)
* .ZIP File (Windows)
How do I build gd?
In order to build gd, you must first unpack the archive you have
downloaded. If you are not familiar with tar and gunzip (Unix) or ZIP
(Windows), please consult with an experienced user of your system.
Sorry, we cannot answer questions about basic Internet skills.
Unpacking the archive will produce a directory called "gd-1.8.4".
For Unix
cd to the 1.8.4 directory. Edit the Makefile with your preferred text
editor and make any necessary changes to the settings at the top,
especially if you want Xpm or TrueType support. Next, type "make". If
you are the system administrator, and you wish to make the gd library
available to other programs, you may also wish to type "make install".
If you get errors, edit the Makefile again, paying special attention
to the INCLUDEDIRS and LIBDIRS settings.
IF YOU GET LINKER ERRORS, TRY JUGGLING THE ORDER OF THE -l DIRECTIVES
IN THE MAKEFILE. Some platforms may prefer that the libraries be
listed in the opposite order.
For Windows, Mac, Et Cetera
Create a project using your favorite programming environment. Copy all
of the gd files to the project directory. Add gd.c to your project.
Add other source files as appropriate. Learning the basic skills of
creating projects with your chosen C environment is up to you.
You have now built both the gd library and a demonstration program
which shows off the capabilities of gd. To see it in action, type
"gddemo".
gddemo should execute without incident, creating the file demoout.png.
(Note there is also a file named demoin.png, which is provided in the
package as part of the demonstration.)
Display demoout.png in your PNG viewer. The image should be 128x128
pixels and should contain an image of the space shuttle with quite a
lot of graphical elements drawn on top of it.
(If you are missing the demoin.png file, the other items should appear
anyway.)
Look at demoin.png to see the original space shuttle image which was
scaled and copied into the output image.
gd basics: using gd in your program
gd lets you create PNG or JPEG images on the fly. To use gd in your
program, include the file gd.h, and link with the libgd.a library
produced by "make libgd.a", under Unix. Under other operating systems
you will add gd.c to your own project.
If you want to use the provided fonts, include gdfontt.h, gdfonts.h,
gdfontmb.h, gdfontl.h and/or gdfontg.h. For more impressive results,
install FreeType 2.x and use the new gdImageStringFT function. If you
are not using the provided Makefile and/or a library-based approach,
be sure to include the source modules as well in your project. (They
may be too large for 16-bit memory models, that is, 16-bit DOS and
Windows.)
Here is a short example program. _(For a more advanced example, see
gddemo.c, included in the distribution. gddemo.c is NOT the same
program; it demonstrates additional features!)_
/* Bring in gd library functions */
#include "gd.h"
/* Bring in standard I/O so we can output the PNG to a file */
#include <stdio.h>
int main() {
/* Declare the image */
gdImagePtr im;
/* Declare output files */
FILE *pngout, *jpegout;
/* Declare color indexes */
int black;
int white;
/* Allocate the image: 64 pixels across by 64 pixels tall */
im = gdImageCreate(64, 64);
/* Allocate the color black (red, green and blue all minimum).
Since this is the first color in a new image, it will
be the background color. */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a line from the upper left to the lower right,
using white color index. */
gdImageLine(im, 0, 0, 63, 63, white);
/* Open a file for writing. "wb" means "write binary", important
under MSDOS, harmless under Unix. */
pngout = fopen("test.png", "wb");
/* Do the same for a JPEG-format file. */
jpegout = fopen("test.jpg", "wb");
/* Output the image to the disk file in PNG format. */
gdImagePng(im, pngout);
/* Output the same image in JPEG format, using the default
JPEG quality setting. */
gdImageJpeg(im, jpegout, -1);
/* Close the files. */
fclose(pngout);
fclose(jpegout);
/* Destroy the image in memory. */
gdImageDestroy(im);
}
When executed, this program creates an image, allocates two colors
(the first color allocated becomes the background color), draws a
diagonal line (note that 0, 0 is the upper left corner), writes the
image to PNG and JPEG files, and destroys the image.
The above example program should give you an idea of how the package
works. gd provides many additional functions, which are listed in the
following reference chapters, complete with code snippets
demonstrating each. There is also an alphabetical index.
Webpng: a more powerful gd example
Webpng is a simple utility program to manipulate PNGs from the command
line. It is written for Unix and similar command-line systems, but
should be easily adapted for other environments. Webpng allows you to
set transparency and interlacing and output interesting information
about the PNG in question.
webpng.c is provided in the distribution. Unix users can simply type
"make webpng" to compile the program. Type "webpng" with no arguments
to see the available options.
Function and type reference
* Types
* Image creation, destruction, loading and saving
* Drawing, styling, brushing, tiling and filling functions
* Query functions (not color-related)
* Font and text-handling functions
* Color handling functions
* Copying and resizing functions
* Miscellaneous Functions
* Constants
Types
gdImage_(TYPE)_
The data structure in which gd stores images. gdImageCreate
returns a pointer to this type, and the other functions expect
to receive a pointer to this type as their first argument. You
may read the members sx (size on X axis), sy (size on Y axis),
colorsTotal (total colors), red (red component of colors; an
array of 256 integers between 0 and 255), green (green
component of colors, as above), blue (blue component of colors,
as above), and transparent (index of transparent color, -1 if
none); please do so using the macros provided. Do NOT set the
members directly from your code; use the functions provided.
typedef struct {
unsigned char ** pixels;
int sx;
int sy;
int colorsTotal;
int red[gdMaxColors];
int green[gdMaxColors];
int blue[gdMaxColors];
int open[gdMaxColors];
int transparent;
} gdImage;
gdImagePtr _(TYPE)_
A pointer to an image structure. gdImageCreate returns this
type, and the other functions expect it as the first argument.
gdFont _(TYPE)_
A font structure. Used to declare the characteristics of a
font. Plese see the files gdfontl.c and gdfontl.h for an
example of the proper declaration of this structure. You can
provide your own font data by providing such a structure and
the associated pixel array. You can determine the width and
height of a single character in a font by examining the w and h
members of the structure. If you will not be creating your own
fonts, you will not need to concern yourself with the rest of
the components of this structure.
typedef struct {
/* # of characters in font */
int nchars;
/* First character is numbered... (usually 32 = space) */
int offset;
/* Character width and height */
int w;
int h;
/* Font data; array of characters, one row after another.
Easily included in code, also easily loaded from
data files. */
char *data;
} gdFont;
gdFontPtr _(TYPE)_
A pointer to a font structure. Text-output functions expect
these as their second argument, following the gdImagePtr
argument. Two such pointers are declared in the provided
include files gdfonts.h and gdfontl.h.
gdPoint _(TYPE)_
Represents a point in the coordinate space of the image; used
by gdImagePolygon and gdImageFilledPolygon.
typedef struct {
int x, y;
} gdPoint, *gdPointPtr;
gdPointPtr _(TYPE)_
A pointer to a gdPoint structure; passed as an argument to
gdImagePolygon and gdImageFilledPolygon.
gdSource _(TYPE)_
typedef struct {
int (*source) (void *context, char *buffer, int len);
void *context;
} gdSource, *gdSourcePtr;
Represents a source from which a PNG can be read. Programmers who do
not wish to read PNGs from a file can provide their own alternate
input mechanism, using the gdImageCreateFromPngSource function. See
the documentation of that function for an example of the proper use of
this type.
gdSink _(TYPE)_
typedef struct {
int (*sink) (void *context, char *buffer, int len);
void *context;
} gdSink, *gdSinkPtr;
Represents a "sink" (destination) to which a PNG can be written.
Programmers who do not wish to write PNGs to a file can provide their
own alternate output mechanism, using the gdImagePngToSink function.
See the documentation of that function for an example of the proper
use of this type.
Image creation, destruction, loading and saving
gdImageCreate(sx, sy) _(FUNCTION)_
gdImageCreate is called to create images. Invoke gdImageCreate
with the x and y dimensions of the desired image. gdImageCreate
returns a gdImagePtr to the new image, or NULL if unable to
allocate the image. The image must eventually be destroyed
using gdImageDestroy().
... inside a function ...
gdImagePtr im;
im = gdImageCreate(64, 64);
/* ... Use the image ... */
gdImageDestroy(im);
gdImageCreateFromJpeg(FILE *in) _(FUNCTION)_
gdImageCreateFromJpegCtx(FILE *in) _(FUNCTION)_
gdImageCreateFromJpeg is called to load images from JPEG format
files. Invoke gdImageCreateFromJpeg with an already opened
pointer to a file containing the desired image.
gdImageCreateFromJpeg returns a gdImagePtr to the new image, or
NULL if unable to load the image (most often because the file
is corrupt or does not contain a JPEG image).
gdImageCreateFromPng does _not_ close the file. You can inspect
the sx and sy members of the image to determine its size. The
image must eventually be destroyed using gdImageDestroy().
gdImagePtr im;
... inside a function ...
FILE *in;
in = fopen("myjpeg.jpg", "rb");
im = gdImageCreateFromJpeg(in);
fclose(in);
/* ... Use the image ... */
gdImageDestroy(im);
gdImageCreateFromPng(FILE *in) _(FUNCTION)_
gdImageCreateFromPngCtx(gdIOCtx *in) _(FUNCTION)_
gdImageCreateFromPng is called to load images from PNG format
files. Invoke gdImageCreateFromPng with an already opened
pointer to a file containing the desired image.
gdImageCreateFromPng returns a gdImagePtr to the new image, or
NULL if unable to load the image (most often because the file
is corrupt or does not contain a PNG image).
gdImageCreateFromPng does _not_ close the file. You can inspect
the sx and sy members of the image to determine its size. The
image must eventually be destroyed using gdImageDestroy().
gdImagePtr im;
... inside a function ...
FILE *in;
in = fopen("mypng.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
/* ... Use the image ... */
gdImageDestroy(im);
gdImageCreateFromPngSource(gdSourcePtr in) _(FUNCTION)_
gdImageCreateFromPngSource is called to load a PNG from a data
source other than a file. Usage is very similar to the
gdImageCreateFromPng function, except that the programmer
provides a custom data source.
The programmer must write an input function which accepts a
context pointer, a buffer, and a number of bytes to be read as
arguments. This function must read the number of bytes
requested, unless the end of the file has been reached, in
which case the function should return zero, or an error has
occurred, in which case the function should return -1. The
programmer then creates a gdSource structure and sets the
source pointer to the input function and the context pointer to
any value which is useful to the programmer.
The example below implements gdImageCreateFromPng by creating a
custom data source and invoking gdImageCreateFromPngSource.
static int freadWrapper(void *context, char *buf, int len);
gdImagePtr gdImageCreateFromPng(FILE *in)
{
gdSource s;
s.source = freadWrapper;
s.context = in;
return gdImageCreateFromPngSource(&s);
}
static int freadWrapper(void *context, char *buf, int len)
{
int got = fread(buf, 1, len, (FILE *) context);
return got;
}
gdImageCreateFromGd(FILE *in) _(FUNCTION)_
gdImageCreateFromGdCtx(gdIOCtx *in) _(FUNCTION)_
gdImageCreateFromGd is called to load images from gd format
files. Invoke gdImageCreateFromGd with an already opened
pointer to a file containing the desired image in the gd file
format, which is specific to gd and intended for very fast
loading. (It is _not_ intended for compression; for
compression, use PNG or JPEG.) gdImageCreateFromGd returns a
gdImagePtr to the new image, or NULL if unable to load the
image (most often because the file is corrupt or does not
contain a gd format image). gdImageCreateFromGd does _not_
close the file. You can inspect the sx and sy members of the
image to determine its size. The image must eventually be
destroyed using gdImageDestroy().
... inside a function ...
gdImagePtr im;
FILE *in;
in = fopen("mygd.gd", "rb");
im = gdImageCreateFromGd(in);
fclose(in);
/* ... Use the image ... */
gdImageDestroy(im);
gdImageCreateFromGd2(FILE *in) _(FUNCTION)_
gdImageCreateFromGd2Ctx(gdIOCtx *in) _(FUNCTION)_
gdImageCreateFromGd2 is called to load images from gd2 format
files. Invoke gdImageCreateFromGd2 with an already opened
pointer to a file containing the desired image in the gd2 file
format, which is specific to gd2 and intended for fast loading
of parts of large images. (It is a compressed format, but
generally not as good a LZW compression). gdImageCreateFromGd
returns a gdImagePtr to the new image, or NULL if unable to
load the image (most often because the file is corrupt or does
not contain a gd format image). gdImageCreateFromGd2 does _not_
close the file. You can inspect the sx and sy members of the
image to determine its size. The image must eventually be
destroyed using gdImageDestroy().
... inside a function ...
gdImagePtr im;
FILE *in;
in = fopen("mygd.gd2", "rb");
im = gdImageCreateFromGd2(in);
fclose(in);
/* ... Use the image ... */
gdImageDestroy(im);
gdImageCreateFromGd2Part(FILE *in, int srcX, int srcY, int w, int h)
_(FUNCTION)_
gdImageCreateFromGd2PartCtx(gdIOCtx *in) _(FUNCTION)_
gdImageCreateFromGd2Part is called to load parts of images from
gd2 format files. Invoked in the same way as
gdImageCreateFromGd2, but with extra parameters indicating the
source (x, y) and width/height of the desired image.
gdImageCreateFromGd2Part returns a gdImagePtr to the new image,
or NULL if unable to load the image. The image must eventually
be destroyed using gdImageDestroy().
gdImageCreateFromXbm(FILE *in) _(FUNCTION)_
gdImageCreateFromXbm is called to load images from X bitmap
format files. Invoke gdImageCreateFromXbm with an already
opened pointer to a file containing the desired image.
gdImageCreateFromXbm returns a gdImagePtr to the new image, or
NULL if unable to load the image (most often because the file
is corrupt or does not contain an X bitmap format image).
gdImageCreateFromXbm does _not_ close the file. You can inspect
the sx and sy members of the image to determine its size. The
image must eventually be destroyed using gdImageDestroy().
... inside a function ...
gdImagePtr im;
FILE *in;
in = fopen("myxbm.xbm", "rb");
im = gdImageCreateFromXbm(in);
fclose(in);
/* ... Use the image ... */
gdImageDestroy(im);
gdImageCreateFromXpm(char *filename) _(FUNCTION)_
gdImageCreateFromXbm is called to load images from XPM X Window
System color bitmap format files. This function is available
only if HAVE_XPM is selected in the Makefile and the Xpm
library is linked with the application. Unlike most gd file
functions, the Xpm functions require filenames, not file
pointers. gdImageCreateFromXpm returns a gdImagePtr to the new
image, or NULL if unable to load the image (most often because
the file is corrupt or does not contain an XPM bitmap format
image). You can inspect the sx and sy members of the image to
determine its size. The image must eventually be destroyed
using gdImageDestroy().
... inside a function ...
gdImagePtr im;
FILE *in;
in = fopen("myxpm.xpm", "rb");
im = gdImageCreateFromXpm(in);
fclose(in);
/* ... Use the image ... */
gdImageDestroy(im);
gdImageDestroy(gdImagePtr im) _(FUNCTION)_
gdImageDestroy is used to free the memory associated with an
image. It is important to invoke gdImageDestroy before exiting
your program or assigning a new image to a gdImagePtr variable.
... inside a function ...
gdImagePtr im;
im = gdImageCreate(10, 10);
/* ... Use the image ... */
/* Now destroy it */
gdImageDestroy(im);
void gdImageJpeg(gdImagePtr im, FILE *out, int quality) _(FUNCTION)_
void gdImageJpegCtx(gdImagePtr im, gdIOCtx *out, int quality)
_(FUNCTION)_
gdImageJpeg outputs the specified image to the specified file in JPEG
format. The file must be open for writing. Under MSDOS and all
versions of Windows, it is important to use "wb" as opposed to simply
"w" as the mode when opening the file, and under Unix there is no
penalty for doing so. gdImageJpeg does _not_ close the file; your code
must do so.
If quality is negative, the default IJG JPEG quality value (which
should yield a good general quality / size tradeoff for most
situations) is used. Otherwise, for practical purposes, quality should
be a value in the range 0-95, higher quality values usually implying
both higher quality and larger image sizes.
If you have set image interlacing using gdImageInterlace, this
function will interpret that to mean you wish to output a progressive
JPEG. Some programs (e.g., Web browsers) can display progressive JPEGs
incrementally; this can be useful when browsing over a relatively slow
communications link, for example. Progressive JPEGs can also be
slightly smaller than sequential (non-progressive) JPEGs.
... inside a function ...
gdImagePtr im;
int black, white;
FILE *out;
/* Create the image */
im = gdImageCreate(100, 100);
/* Allocate background */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate drawing color */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Draw rectangle */
gdImageRectangle(im, 0, 0, 99, 99, black);
/* Open output file in binary mode */
out = fopen("rect.jpg", "wb");
/* Write JPEG using default quality */
gdImageJpeg(im, out, -1);
/* Close file */
fclose(out);
/* Destroy image */
gdImageDestroy(im);
void* gdImageJpegPtr(gdImagePtr im, int *size) _(FUNCTION)_
Identical to gdImageJpeg except that it returns a pointer to a memory
area with the JPEG data. This memory must be freed by the caller when
it is no longer needed. _The caller must invoke gdFree(), not free(),
unless the caller is absolutely certain that the same implementations
of malloc, free, etc. are used both at library build time and at
application build time._ The 'size' parameter receives the total size
of the block of memory.
void gdImagePng(gdImagePtr im, FILE *out) _(FUNCTION)_
gdImagePng outputs the specified image to the specified file in PNG
format. The file must be open for writing. Under MSDOS and all
versions of Windows, it is important to use "wb" as opposed to simply
"w" as the mode when opening the file, and under Unix there is no
penalty for doing so. gdImagePng does _not_ close the file; your code
must do so.
... inside a function ...
gdImagePtr im;
int black, white;
FILE *out;
/* Create the image */
im = gdImageCreate(100, 100);
/* Allocate background */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate drawing color */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Draw rectangle */
gdImageRectangle(im, 0, 0, 99, 99, black);
/* Open output file in binary mode */
out = fopen("rect.png", "wb");
/* Write PNG */
gdImagePng(im, out);
/* Close file */
fclose(out);
/* Destroy image */
gdImageDestroy(im);
void* gdImagePngPtr(gdImagePtr im, int *size) _(FUNCTION)_
Identical to gdImagePng except that it returns a pointer to a memory
area with the PNG data. This memory must be freed by the caller when
it is no longer needed. _The caller must invoke gdFree(), not free(),
unless the caller is absolutely certain that the same implementations
of malloc, free, etc. are used both at library build time and at
application build time._ The 'size' parameter receives the total size
of the block of memory.
gdImagePngToSink(gdImagePtr im, gdSinkPtr out) _(FUNCTION)_
gdImagePngToSink is called to write a PNG to a data "sink"
(destination) other than a file. Usage is very similar to the
gdImagePng function, except that the programmer provides a custom data
sink.
The programmer must write an output function which accepts a context
pointer, a buffer, and a number of bytes to be written as arguments.
This function must write the number of bytes requested and return that
number, unless an error has occurred, in which case the function
should return -1. The programmer then creates a gdSink structure and
sets the sink pointer to the output function and the context pointer
to any value which is useful to the programmer.
The example below implements gdImagePng by creating a custom data
source and invoking gdImagePngFromSink.
static int stdioSink(void *context, char *buffer, int len)
{
return fwrite(buffer, 1, len, (FILE *) context);
}
void gdImagePng(gdImagePtr im, FILE *out)
{
gdSink mySink;
mySink.context = (void *) out;
mySink.sink = stdioSink;
gdImagePngToSink(im, &mySink);
}
void gdImageWBMP(gdImagePtr im, int fg, FILE *out)
gdImageWBMPCtx(gdIOCtx *out) _(FUNCTION)__(FUNCTION)_
gdImageWBMP outputs the specified image to the specified file in WBMP
format. The file must be open for writing. Under MSDOS and all
versions of Windows, it is important to use "wb" as opposed to simply
"w" as the mode when opening the file, and under Unix there is no
penalty for doing so. gdImageWBMP does _not_ close the file; your code
must do so.
_WBMP file support is black and white only. The color index specified
by the fg argument is the "foreground," and only pixels of this color
will be set in the WBMP file._ All other pixels will be considered
"background."
... inside a function ...
gdImagePtr im;
int black, white;
FILE *out;
/* Create the image */
im = gdImageCreate(100, 100);
/* Allocate background */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate drawing color */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Draw rectangle */
gdImageRectangle(im, 0, 0, 99, 99, black);
/* Open output file in binary mode */
out = fopen("rect.wbmp", "wb");
/* Write WBMP, with black as foreground */
gdImageWBMP(im, black, out);
/* Close file */
fclose(out);
/* Destroy image */
gdImageDestroy(im);
void* gdImageWBMPPtr(gdImagePtr im, int *size) _(FUNCTION)_
Identical to gdImageWBMP except that it returns a pointer to a memory
area with the WBMP data. This memory must be freed by the caller when
it is no longer needed. _The caller must invoke gdFree(), not free(),
unless the caller is absolutely certain that the same implementations
of malloc, free, etc. are used both at library build time and at
application build time._ The 'size' parameter receives the total size
of the block of memory.
void gdImageGd(gdImagePtr im, FILE *out) _(FUNCTION)_
gdImageGd outputs the specified image to the specified file in the gd
image format. The file must be open for writing. Under MSDOS and all
versions of Windows, it is important to use "wb" as opposed to simply
"w" as the mode when opening the file, and under Unix there is no
penalty for doing so. gdImagePng does _not_ close the file; your code
must do so.
The gd image format is intended for fast reads and writes of images
your program will need frequently to build other images. It is _not_ a
compressed format, and is not intended for general use.
... inside a function ...
gdImagePtr im;
int black, white;
FILE *out;
/* Create the image */
im = gdImageCreate(100, 100);
/* Allocate background */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate drawing color */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Draw rectangle */
gdImageRectangle(im, 0, 0, 99, 99, black);
/* Open output file in binary mode */
out = fopen("rect.gd", "wb");
/* Write gd format file */
gdImageGd(im, out);
/* Close file */
fclose(out);
/* Destroy image */
gdImageDestroy(im);
void* gdImageGdPtr(gdImagePtr im, int *size) _(FUNCTION)_
Identical to gdImageGd except that it returns a pointer to a memory
area with the GD data. This memory must be freed by the caller when it
is no longer needed. _The caller must invoke gdFree(), not free(),
unless the caller is absolutely certain that the same implementations
of malloc, free, etc. are used both at library build time and at
application build time._ The 'size' parameter receives the total size
of the block of memory.
void gdImageGd2(gdImagePtr im, FILE *out, int chunkSize, int fmt)
_(FUNCTION)_
gdImageGd2 outputs the specified image to the specified file in the
gd2 image format. The file must be open for writing. Under MSDOS and
all versions of Windows, it is important to use "wb" as opposed to
simply "w" as the mode when opening the file, and under Unix there is
no penalty for doing so. gdImageGd2 does _not_ close the file; your
code must do so.
The gd2 image format is intended for fast reads and writes of parts of
images. It is a compressed format, and well suited to retrieving smll
sections of much larger images. The third and fourth parameters are
the 'chunk size' and format resposectively.
The file is stored as a series of compressed subimages, and the _Chunk
Size_ determines the sub-image size - a value of zero causes the GD
library to use the default.
It is also possible to store GD2 files in an uncompressed format, in
which case the fourth parameter should be GD2_FMT_RAW.
... inside a function ...
gdImagePtr im;
int black, white;
FILE *out;
/* Create the image */
im = gdImageCreate(100, 100);
/* Allocate background */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate drawing color */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Draw rectangle */
gdImageRectangle(im, 0, 0, 99, 99, black);
/* Open output file in binary mode */
out = fopen("rect.gd", "wb");
/* Write gd2 format file */
gdImageGd2(im, out, 0, GD2_FMT_COMPRESSED);
/* Close file */
fclose(out);
/* Destroy image */
gdImageDestroy(im);
void* gdImageGd2Ptr(gdImagePtr im, int chunkSize, int fmt, int *size)
_(FUNCTION)_
Identical to gdImageGd2 except that it returns a pointer to a memory
area with the GD2 data. This memory must be freed by the caller when
it is no longer needed. _The caller must invoke gdFree(), not free(),
unless the caller is absolutely certain that the same implementations
of malloc, free, etc. are used both at library build time and at
application build time._ The 'size' parameter receives the total size
of the block of memory.
Drawing Functions
void gdImageSetPixel(gdImagePtr im, int x, int y, int color)
_(FUNCTION)_
gdImageSetPixel sets a pixel to a particular color index.
Always use this function or one of the other drawing functions
to access pixels; do not access the pixels of the gdImage
structure directly.
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Set a pixel near the center. */
gdImageSetPixel(im, 50, 50, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageLine(gdImagePtr im, int x1, int y1, int x2, int y2, int
color) _(FUNCTION)_
gdImageLine is used to draw a line between two endpoints (x1,y1
and x2, y2). The line is drawn using the color index specified.
Note that the color index can be an actual color returned by
gdImageColorAllocate or one of gdStyled, gdBrushed or
gdStyledBrushed.
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a line from the upper left corner to the lower right corner. */
gdImageLine(im, 0, 0, 99, 99, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageDashedLine(gdImagePtr im, int x1, int y1, int x2, int y2,
int color) _(FUNCTION)_
gdImageDashedLine is provided _solely for backwards
compatibility _with gd 1.0. New programs should draw dashed
lines using the normal gdImageLine function and the new
gdImageSetStyle function.
gdImageDashedLine is used to draw a dashed line between two
endpoints (x1,y1 and x2, y2). The line is drawn using the color
index specified. The portions of the line that are not drawn
are left transparent so the background is visible.
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a dashed line from the upper left corner to the lower right corner. */
gdImageDashedLine(im, 0, 0, 99, 99);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImagePolygon(gdImagePtr im, gdPointPtr points, int pointsTotal,
int color) _(FUNCTION)_
gdImagePolygon is used to draw a polygon with the verticies (at
least 3) specified, using the color index specified. See also
gdImageFilledPolygon.
... inside a function ...
gdImagePtr im;
int black;
int white;
/* Points of polygon */
gdPoint points[3];
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a triangle. */
points[0].x = 50;
points[0].y = 0;
points[1].x = 99;
points[1].y = 99;
points[2].x = 0;
points[2].y = 99;
gdImagePolygon(im, points, 3, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageRectangle(gdImagePtr im, int x1, int y1, int x2, int y2,
int color) _(FUNCTION)_
gdImageRectangle is used to draw a rectangle with the two
corners (upper left first, then lower right) specified, using
the color index specified.
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a rectangle occupying the central area. */
gdImageRectangle(im, 25, 25, 74, 74, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageFilledPolygon(gdImagePtr im, gdPointPtr points, int
pointsTotal, int color) _(FUNCTION)_
gdImageFilledPolygon is used to fill a polygon with the
verticies (at least 3) specified, using the color index
specified. See also gdImagePolygon.
... inside a function ...
gdImagePtr im;
int black;
int white;
int red;
/* Points of polygon */
gdPoint points[3];
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate the color red. */
red = gdImageColorAllocate(im, 255, 0, 0);
/* Draw a triangle. */
points[0].x = 50;
points[0].y = 0;
points[1].x = 99;
points[1].y = 99;
points[2].x = 0;
points[2].y = 99;
/* Paint it in white */
gdImageFilledPolygon(im, points, 3, white);
/* Outline it in red; must be done second */
gdImagePolygon(im, points, 3, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageFilledRectangle(gdImagePtr im, int x1, int y1, int x2, int
y2, int color) _(FUNCTION)_
gdImageFilledRectangle is used to draw a solid rectangle with
the two corners (upper left first, then lower right) specified,
using the color index specified.
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = int gdImageColorAllocate(im, 255, 255, 255);
/* Draw a filled rectangle occupying the central area. */
gdImageFilledRectangle(im, 25, 25, 74, 74, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageArc(gdImagePtr im, int cx, int cy, int w, int h, int s,
int e, int color) _(FUNCTION)_
gdImageArc is used to draw a partial ellipse centered at the
given point, with the specified width and height in pixels. The
arc begins at the position in degrees specified by s and ends
at the position specified by e. The arc is drawn in the color
specified by the last argument. A circle can be drawn by
beginning from 0 degrees and ending at 360 degrees, with width
and height being equal. e must be greater than s. Values
greater than 360 are interpreted modulo 360.
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 50);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Inscribe an ellipse in the image. */
gdImageArc(im, 50, 25, 98, 48, 0, 360, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageFillToBorder(gdImagePtr im, int x, int y, int border, int
color) _(FUNCTION)_
gdImageFillToBorder floods a portion of the image with the
specified color, beginning at the specified point and stopping
at the specified border color. For a way of flooding an area
defined by the color of the starting point, see gdImageFill.
The border color _cannot_ be a special color such as gdTiled;
it must be a proper solid color. The fill color can be,
however.
Note that gdImageFillToBorder is recursive. It is not the most
naive implementation possible, and the implementation is
expected to improve, but there will always be degenerate cases
in which the stack can become very deep. This can be a problem
in MSDOS and MS Windows 3.1 environments. (Of course, in a Unix
or Windows 95/98/NT environment with a proper stack, this is
not a problem at all.)
... inside a function ...
gdImagePtr im;
int black;
int white;
int red;
im = gdImageCreate(100, 50);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate the color red. */
red = gdImageColorAllocate(im, 255, 0, 0);
/* Inscribe an ellipse in the image. */
gdImageArc(im, 50, 25, 98, 48, 0, 360, white);
/* Flood-fill the ellipse. Fill color is red, border color is
white (ellipse). */
gdImageFillToBorder(im, 50, 50, white, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageFill(gdImagePtr im, int x, int y, int color) _(FUNCTION)_
gdImageFill floods a portion of the image with the specified
color, beginning at the specified point and flooding the
surrounding region of the same color as the starting point. For
a way of flooding a region defined by a specific border color
rather than by its interior color, see gdImageFillToBorder.
The fill color can be gdTiled, resulting in a tile fill using
another image as the tile. However, the tile image cannot be
transparent. If the image you wish to fill with has a
transparent color index, call gdImageTransparent on the tile
image and set the transparent color index to -1 to turn off its
transparency.
Note that gdImageFill is recursive. It is not the most naive
implementation possible, and the implementation is expected to
improve, but there will always be degenerate cases in which the
stack can become very deep. This can be a problem in MSDOS and
MS Windows environments. (Of course, in a Unix or Windows
95/98/NT environment with a proper stack, this is not a problem
at all.)
... inside a function ...
gdImagePtr im;
int black;
int white;
int red;
im = gdImageCreate(100, 50);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Allocate the color red. */
red = gdImageColorAllocate(im, 255, 0, 0);
/* Inscribe an ellipse in the image. */
gdImageArc(im, 50, 25, 98, 48, 0, 360, white);
/* Flood-fill the ellipse. Fill color is red, and will replace the
black interior of the ellipse. */
gdImageFill(im, 50, 50, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageSetBrush(gdImagePtr im, gdImagePtr brush) _(FUNCTION)_
A "brush" is an image used to draw wide, shaped strokes in
another image. Just as a paintbrush is not a single point, a
brush image need not be a single pixel. _Any_ gd image can be
used as a brush, and by setting the transparent color index of
the brush image with gdImageColorTransparent, a brush of any
shape can be created. All line-drawing functions, such as
gdImageLine and gdImagePolygon, will use the current brush if
the special "color" gdBrushed or gdStyledBrushed is used when
calling them.
gdImageSetBrush is used to specify the brush to be used in a
particular image. You can set any image to be the brush. If the
brush image does not have the same color map as the first
image, any colors missing from the first image will be
allocated. If not enough colors can be allocated, the closest
colors already available will be used. This allows arbitrary
PNGs to be used as brush images. It also means, however, that
you should not set a brush unless you will actually use it; if
you set a rapid succession of different brush images, you can
quickly fill your color map, and the results will not be
optimal.
You need not take any special action when you are finished with
a brush. As for any other image, if you will not be using the
brush image for any further purpose, you should call
gdImageDestroy. You must not use the color gdBrushed if the
current brush has been destroyed; you can of course set a new
brush to replace it.
... inside a function ...
gdImagePtr im, brush;
FILE *in;
int black;
im = gdImageCreate(100, 100);
/* Open the brush PNG. For best results, portions of the
brush that should be transparent (ie, not part of the
brush shape) should have the transparent color index. */
in = fopen("star.png", "rb");
brush = gdImageCreateFromPng(in);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
gdImageSetBrush(im, brush);
/* Draw a line from the upper left corner to the lower right corner
using the brush. */
gdImageLine(im, 0, 0, 99, 99, gdBrushed);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
/* Destroy the brush image */
gdImageDestroy(brush);
void gdImageSetTile(gdImagePtr im, gdImagePtr tile) _(FUNCTION)_
A "tile" is an image used to fill an area with a repeated
pattern. _Any_ gd image can be used as a tile, and by setting
the transparent color index of the tile image with
gdImageColorTransparent, a tile that allows certain parts of
the underlying area to shine through can be created. All
region-filling functions, such as gdImageFill and
gdImageFilledPolygon, will use the current tile if the special
"color" gdTiled is used when calling them.
gdImageSetTile is used to specify the tile to be used in a
particular image. You can set any image to be the tile. If the
tile image does not have the same color map as the first image,
any colors missing from the first image will be allocated. If
not enough colors can be allocated, the closest colors already
available will be used. This allows arbitrary PNGs to be used
as tile images. It also means, however, that you should not set
a tile unless you will actually use it; if you set a rapid
succession of different tile images, you can quickly fill your
color map, and the results will not be optimal.
You need not take any special action when you are finished with
a tile. As for any other image, if you will not be using the
tile image for any further purpose, you should call
gdImageDestroy. You must not use the color gdTiled if the
current tile has been destroyed; you can of course set a new
tile to replace it.
... inside a function ...
gdImagePtr im, tile;
FILE *in;
int black;
im = gdImageCreate(100, 100);
/* Open the tile PNG. For best results, portions of the
tile that should be transparent (ie, allowing the
background to shine through) should have the transparent
color index. */
in = fopen("star.png", "rb");
tile = gdImageCreateFromPng(in);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
gdImageSetTile(im, tile);
/* Fill an area using the tile. */
gdImageFilledRectangle(im, 25, 25, 75, 75, gdTiled);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
/* Destroy the tile image */
gdImageDestroy(tile);
void gdImageSetStyle(gdImagePtr im, int *style, int styleLength)
_(FUNCTION)_
It is often desirable to draw dashed lines, dotted lines, and
other variations on a broken line. gdImageSetStyle can be used
to set any desired series of colors, including a special color
that leaves the background intact, to be repeated during the
drawing of a line.
To use gdImageSetStyle, create an array of integers and assign
them the desired series of color values to be repeated. You can
assign the special color value gdTransparent to indicate that
the existing color should be left unchanged for that particular
pixel (allowing a dashed line to be attractively drawn over an
existing image).
Then, to draw a line using the style, use the normal
gdImageLine function with the special color value gdStyled.
As of version 1.1.1, the style array is copied when you set the
style, so you need not be concerned with keeping the array
around indefinitely. This should not break existing code that
assumes styles are not copied.
You can also combine styles and brushes to draw the brush image
at intervals instead of in a continuous stroke. When creating a
style for use with a brush, the style values are interpreted
differently: zero (0) indicates pixels at which the brush
should not be drawn, while one (1) indicates pixels at which
the brush should be drawn. To draw a styled, brushed line, you
must use the special color value gdStyledBrushed. For an
example of this feature in use, see gddemo.c (provided in the
distribution).
gdImagePtr im;
int styleDotted[2], styleDashed[6];
FILE *in;
int black;
int red;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
red = gdImageColorAllocate(im, 255, 0, 0);
/* Set up dotted style. Leave every other pixel alone. */
styleDotted[0] = red;
styleDotted[1] = gdTransparent;
/* Set up dashed style. Three on, three off. */
styleDashed[0] = red;
styleDashed[1] = red;
styleDashed[2] = red;
styleDashed[3] = gdTransparent;
styleDashed[4] = gdTransparent;
styleDashed[5] = gdTransparent;
/* Set dotted style. Note that we have to specify how many pixels are
in the style! */
gdImageSetStyle(im, styleDotted, 2);
/* Draw a line from the upper left corner to the lower right corner. */
gdImageLine(im, 0, 0, 99, 99, gdStyled);
/* Now the dashed line. */
gdImageSetStyle(im, styleDashed, 6);
gdImageLine(im, 0, 99, 0, 99, gdStyled);
/* ... Do something with the image, such as saving it to a file ... */
/* Destroy it */
gdImageDestroy(im);
Query Functions
int gdImageBlue(gdImagePtr im, int color) _(MACRO)_
gdImageBlue is a macro which returns the blue component
of the specified color index. Use this macro rather than
accessing the structure members directly.
int gdImageGetPixel(gdImagePtr im, int x, int y) _(FUNCTION)_
gdImageGetPixel() retrieves the color index of a
particular pixel. Always use this function to query
pixels; do not access the pixels of the gdImage structure
directly.
... inside a function ...
FILE *in;
gdImagePtr im;
int c;
in = fopen("mypng.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
c = gdImageGetPixel(im, gdImageSX(im) / 2, gdImageSY(im) / 2);
printf("The value of the center pixel is %d; RGB values are %d,%d,%d\n",
c, im->red[c], im->green[c], im->blue[c]);
gdImageDestroy(im);
int gdImageBoundsSafe(gdImagePtr im, int x, int y) _(FUNCTION)_
gdImageBoundsSafe returns true (1) if the specified point
is within the bounds of the image, false (0) if not. This
function is intended primarily for use by those who wish
to add functions to gd. All of the gd drawing functions
already clip safely to the edges of the image.
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
if (gdImageBoundsSafe(im, 50, 50)) {
printf("50, 50 is within the image bounds\n");
} else {
printf("50, 50 is outside the image bounds\n");
}
gdImageDestroy(im);
int gdImageGreen(gdImagePtr im, int color) _(MACRO)_
gdImageGreen is a macro which returns the green component
of the specified color index. Use this macro rather than
accessing the structure members directly.
int gdImageRed(gdImagePtr im, int color) _(MACRO)_
gdImageRed is a macro which returns the red component of
the specified color index. Use this macro rather than
accessing the structure members directly.
int gdImageSX(gdImagePtr im) _(MACRO)_
gdImageSX is a macro which returns the width of the image
in pixels. Use this macro rather than accessing the
structure members directly.
int gdImageSY(gdImagePtr im) _(MACRO)_
gdImageSY is a macro which returns the height of the
image in pixels. Use this macro rather than accessing the
structure members directly.
Fonts and text-handling functions
void gdImageChar(gdImagePtr im, gdFontPtr font, int x, int y, int
c, int color) _(FUNCTION)_
gdImageChar is used to draw single characters on the
image. (To draw multiple characters, use gdImageString or
gdImageString16. See also gdImageStringFT for a high
quality solution.) The second argument is a pointer to a
font definition structure; five fonts are provided with
gd, gdFontTiny, gdFontSmall, gdFontMediumBold,
gdFontLarge, and gdFontGiant. You must include the files
"gdfontt.h", "gdfonts.h", "gdfontmb.h", "gdfontl.h" and
"gdfontg.h" respectively and (if you are not using a
library-based approach) link with the corresponding .c
files to use the provided fonts. The character specified
by the fifth argument is drawn from left to right in the
specified color. (See gdImageCharUp for a way of drawing
vertical text.) Pixels not set by a particular character
retain their previous color.
#include "gd.h"
#include "gdfontl.h"
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a character. */
gdImageChar(im, gdFontLarge, 0, 0, 'Q', white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageCharUp(gdImagePtr im, gdFontPtr font, int x, int y,
int c, int color) _(FUNCTION)_
gdImageCharUp is used to draw single characters on the
image, rotated 90 degrees. (To draw multiple characters,
use gdImageStringUp or gdImageStringUp16.) The second
argument is a pointer to a font definition structure;
five fonts are provided with gd, gdFontTiny, gdFontSmall,
gdFontMediumBold, gdFontLarge, and gdFontGiant. You must
include the files "gdfontt.h", "gdfonts.h", "gdfontmb.h",
"gdfontl.h" and "gdfontg.h" respectively and (if you are
not using a library-based approach) link with the
corresponding .c files to use the provided fonts. The
character specified by the fifth argument is drawn from
bottom to top, rotated at a 90-degree angle, in the
specified color. (See gdImageChar for a way of drawing
horizontal text.) Pixels not set by a particular
character retain their previous color.
#include "gd.h"
#include "gdfontl.h"
... inside a function ...
gdImagePtr im;
int black;
int white;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a character upwards so it rests against the top of the image. */
gdImageCharUp(im, gdFontLarge,
0, gdFontLarge->h, 'Q', white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageString(gdImagePtr im, gdFontPtr font, int x, int y,
unsigned char *s, int color) _(FUNCTION)_
gdImageString is used to draw multiple characters on the
image. (To draw single characters, use gdImageChar.) The
second argument is a pointer to a font definition
structure; five fonts are provided with gd, gdFontTiny,
gdFontSmall, gdFontMediumBold, gdFontLarge, and
gdFontGiant. You must include the files "gdfontt.h",
"gdfonts.h", "gdfontmb.h", "gdfontl.h" and "gdfontg.h"
respectively and (if you are not using a library-based
approach) link with the corresponding .c files to use the
provided fonts. The null-terminated C string specified by
the fifth argument is drawn from left to right in the
specified color. (See gdImageStringUp for a way of
drawing vertical text. See also gdImageStringFT for a
high quality solution.) Pixels not set by a particular
character retain their previous color.
#include "gd.h"
#include "gdfontl.h"
#include <string.h>
... inside a function ...
gdImagePtr im;
int black;
int white;
/* String to draw. */
char *s = "Hello.";
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a centered string. */
gdImageString(im, gdFontLarge,
im->w / 2 - (strlen(s) * gdFontLarge->w / 2),
im->h / 2 - gdFontLarge->h / 2,
s, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageString16(gdImagePtr im, gdFontPtr font, int x, int y,
unsigned short *s, int color) _(FUNCTION)_
gdImageString is used to draw multiple 16-bit characters
on the image. (To draw single characters, use
gdImageChar.) The second argument is a pointer to a font
definition structure; five fonts are provided with gd,
gdFontTiny, gdFontSmall, gdFontMediumBold, gdFontLarge,
and gdFontGiant. You must include the files "gdfontt.h",
"gdfonts.h", "gdfontmb.h", "gdfontl.h" and "gdfontg.h"
respectively and (if you are not using a library-based
approach) link with the corresponding .c files to use the
provided fonts. The null-terminated string of characters
represented as 16-bit unsigned short integers specified
by the fifth argument is drawn from left to right in the
specified color. (See gdImageStringUp16 for a way of
drawing vertical text.) Pixels not set by a particular
character retain their previous color.
This function was added in gd1.3 to provide a means of
rendering fonts with more than 256 characters for those
who have them. A more frequently used routine is
gdImageString.
void gdImageStringUp(gdImagePtr im, gdFontPtr font, int x, int y,
unsigned char *s, int color) _(FUNCTION)_
gdImageStringUp is used to draw multiple characters on
the image, rotated 90 degrees. (To draw single
characters, use gdImageCharUp.) The second argument is a
pointer to a font definition structure; five fonts are
provided with gd, gdFontTiny, gdFontSmall,
gdFontMediumBold, gdFontLarge, and gdFontGiant. You must
include the files "gdfontt.h", "gdfonts.h", "gdfontmb.h",
"gdfontl.h" and "gdfontg.h" respectively and (if you are
not using a library-based approach) link with the
corresponding .c files to use the provided fonts.The
null-terminated C string specified by the fifth argument
is drawn from bottom to top (rotated 90 degrees) in the
specified color. (See gdImageString for a way of drawing
horizontal text.) Pixels not set by a particular
character retain their previous color.
#include "gd.h"
#include "gdfontl.h"
#include <string.h>
... inside a function ...
gdImagePtr im;
int black;
int white;
/* String to draw. */
char *s = "Hello.";
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);
/* Draw a centered string going upwards. Axes are reversed,
and Y axis is decreasing as the string is drawn. */
gdImageStringUp(im, gdFontLarge,
im->w / 2 - gdFontLarge->h / 2,
im->h / 2 + (strlen(s) * gdFontLarge->w / 2),
s, white);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageStringUp16(gdImagePtr im, gdFontPtr font, int x, int
y, unsigned short *s, int color) _(FUNCTION)_
gdImageString is used to draw multiple 16-bit characters
vertically on the image. (To draw single characters, use
gdImageChar.) The second argument is a pointer to a font
definition structure; five fonts are provided with gd,
gdFontTiny, gdFontSmall, gdFontMediumBold, gdFontLarge,
and gdFontGiant. You must include the files "gdfontt.h",
"gdfonts.h", "gdfontmb.h", "gdfontl.h" and "gdfontg.h"
respectively and (if you are not using a library-based
approach) link with the corresponding .c files to use the
provided fonts. The null-terminated string of characters
represented as 16-bit unsigned short integers specified
by the fifth argument is drawn from bottom to top in the
specified color. (See gdImageStringUp16 for a way of
drawing horizontal text.) Pixels not set by a particular
character retain their previous color.
This function was added in gd1.3 to provide a means of
rendering fonts with more than 256 characters for those
who have them. A more frequently used routine is
gdImageStringUp.
char *gdImageStringFT(gdImagePtr im, int *brect, int fg, char
*fontname, double ptsize, double angle, int x, int y,
char *string) _(FUNCTION)_
_RECOMMENDED. New in 1.8.4._ gdImageStringFT draws text
using the FreeType 2.x library.
gdImageStringFT draws a string of anti-aliased characters
on the image using the FreeType library to render
user-supplied TrueType fonts. _We do not provide TrueType
fonts (.ttf and .ttc files). Obtaining them is entirely
up to you._ The string is anti-aliased, meaning that
there should be fewer "jaggies" visible. The fontname is
the full pathname to a TrueType font file, or a font face
name if the GDFONTPATH environment variable or FreeType's
DEFAULT_FONTPATH variable have been set intelligently.
The string may be arbitrarily scaled (ptsize) and rotated
(angle in radians).
The user-supplied int brect[8] array is filled on return
from gdImageStringFT with the 8 elements representing the
4 corner coordinates of the bounding rectangle.
0 lower left corner, X position
lower left corner, Y position
lower right corner, X position
3 lower right corner, Y position
4 upper right corner, X position
5 upper right corner, Y position
6 upper left corner, X position
7 upper left corner, Y position
The points are relative to the text regardless of the
angle, so "upper left" means in the top left-hand corner
seeing the text horizontally.
Use a NULL gdImagePtr to get the bounding rectangle
without rendering. This is a relatively cheap operation
if followed by a rendering of the same string, because of
the caching of the partial rendering during bounding
rectangle calculation.
The string is rendered in the color indicated by the gf
color index. _Use the negative of the desired color index
to disable anti-aliasing._
The string may contain UTF-8 sequences like: "À"
gdImageStringFT will return a null char* on success, or
an error string on failure.
#include "gd.h"
#include <string.h>
... inside a function ...
gdImagePtr im;
int black;
int white;
int brect[8];
int x, y;
char *err;
char *s = "Hello."; /* String to draw. */
double sz = 40.;
char *f = "/usr/local/share/ttf/Times.ttf"; /* User supplied font */
/* obtain brect so that we can size the image */
err = gdImageStringFT(NULL,&brect[0],0,f,sz,0.,0,0,s);
if (err) {fprintf(stderr,err); return 1;}
/* create an image big enough for the string plus a little whitespace */
x = brect[2]-brect[6] + 6;
y = brect[3]-brect[7] + 6;
im = gdImageCreate(x,y);
/* Background color (first allocated) */
white = gdImageColorResolve(im, 255, 255, 255);
black = gdImageColorResolve(im, 0, 0, 0);
/* render the string, offset origin to center string*/
/* note that we use top-left coordinate for adjustment
* since gd origin is in top-left with y increasing downwards. */
x = 3 - brect[6];
y = 3 - brect[7];
err = gdImageStringFT(im,&brect[0],black,f,sz,0.0,x,y,s);
if (err) {fprintf(stderr,err); return 1;}
/* Write img to stdout */
gdImagePng(im, stdout);
/* Destroy it */
gdImageDestroy(im);
char *gdImageStringTTF(gdImagePtr im, int *brect, int fg, char
*fontname, double ptsize, double angle, int x, int y,
char *string) _(FUNCTION)_
_DEPRECATED._ gdImageStringTTF draws text using the
FreeType 1.x library. For better results, use
gdImageStringFT and FreeType 2.x.
gdImageStringTTF draws a string of anti-aliased
characters on the image using the FreeType library to
render user-supplied TrueType fonts. _We do not provide
TrueType fonts (.ttf and .ttc files). Obtaining them is
entirely up to you._ The string is anti-aliased, meaning
that there should be fewer "jaggies" visible. The
fontname is the full pathname to a TrueType font file, or
a font face name if the GDFONTPATH environment variable
or FreeType's DEFAULT_FONTPATH variable have been set
intelligently. The string may be arbitrarily scaled
(ptsize) and rotated (angle in radians).
The user-supplied int brect[8] array is filled on return
from gdImageStringTTF with the 8 elements representing
the 4 corner coordinates of the bounding rectangle.
0 lower left corner, X position
lower left corner, Y position
lower right corner, X position
3 lower right corner, Y position
4 upper right corner, X position
5 upper right corner, Y position
6 upper left corner, X position
7 upper left corner, Y position
The points are relative to the text regardless of the
angle, so "upper left" means in the top left-hand corner
seeing the text horizontally.
Use a NULL gdImagePtr to get the bounding rectangle
without rendering. This is a relatively cheap operation
if followed by a rendering of the same string, because of
the caching of the partial rendering during bounding
rectangle calculation.
The string is rendered in the color indicated by the gf
color index. _Use the negative of the desired color index
to disable anti-aliasing._
The string may contain UTF-8 sequences like: "À"
gdImageStringTTF will return a null char* on success, or
an error string on failure.
#include "gd.h"
#include <string.h>
... inside a function ...
gdImagePtr im;
int black;
int white;
int brect[8];
int x, y;
char *err;
char *s = "Hello."; /* String to draw. */
double sz = 40.;
char *f = "/usr/local/share/ttf/Times.ttf"; /* User supplied font */
/* obtain brect so that we can size the image */
err = gdImageStringTTF(NULL,&brect[0],0,f,sz,0.,0,0,s);
if (err) {fprintf(stderr,err); return 1;}
/* create an image big enough for the string plus a little whitespace */
x = brect[2]-brect[6] + 6;
y = brect[3]-brect[7] + 6;
im = gdImageCreate(x,y);
/* Background color (first allocated) */
white = gdImageColorResolve(im, 255, 255, 255);
black = gdImageColorResolve(im, 0, 0, 0);
/* render the string, offset origin to center string*/
/* note that we use top-left coordinate for adjustment
* since gd origin is in top-left with y increasing downwards. */
x = 3 - brect[6];
y = 3 - brect[7];
err = gdImageStringTTF(im,&brect[0],black,f,sz,0.0,x,y,s);
if (err) {fprintf(stderr,err); return 1;}
/* Write img to stdout */
gdImagePng(im, stdout);
/* Destroy it */
gdImageDestroy(im);
Color-handling functions
int gdImageColorAllocate(gdImagePtr im, int r, int g, int b)
_(FUNCTION)_
gdImageColorAllocate finds the first available color
index in the image specified, sets its RGB values to
those requested (255 is the maximum for each), and
returns the index of the new color table entry. When
creating a new image, the first time you invoke this
function, you are setting the background color for that
image.
In the event that all gdMaxColors colors (256) have
already been allocated, gdImageColorAllocate will return
-1 to indicate failure. (This is not uncommon when
working with existing PNG files that already use 256
colors.) Note that gdImageColorAllocate does not check
for existing colors that match your request; see
gdImageColorExact, gdImageColorClosest and
gdImageColorClosestHWB for ways to locate existing colors
that approximate the color desired in situations where a
new color is not available. Also see gdImageColorResolve,
new in gd-1.6.2.
... inside a function ...
gdImagePtr im;
int black;
int red;
im = gdImageCreate(100, 100);
/* Background color (first allocated) */
black = gdImageColorAllocate(im, 0, 0, 0);
/* Allocate the color red. */
red = gdImageColorAllocate(im, 255, 0, 0);
/* Draw a dashed line from the upper left corner to the lower right corner. */
gdImageDashedLine(im, 0, 0, 99, 99, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
int gdImageColorClosest(gdImagePtr im, int r, int g, int b)
_(FUNCTION)_
gdImageColorClosest searches the colors which have been
defined thus far in the image specified and returns the
index of the color with RGB values closest to those of
the request. (Closeness is determined by Euclidian
distance, which is used to determine the distance in
three-dimensional color space between colors.)
If no colors have yet been allocated in the image,
gdImageColorClosest returns -1.
This function is most useful as a backup method for
choosing a drawing color when an image already contains
gdMaxColors (256) colors and no more can be allocated.
(This is not uncommon when working with existing PNG
files that already use many colors.) See
gdImageColorExact for a method of locating exact matches
only.
... inside a function ...
gdImagePtr im;
FILE *in;
int red;
/* Let's suppose that photo.png is a scanned photograph with
many colors. */
in = fopen("photo.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
/* Try to allocate red directly */
red = gdImageColorAllocate(im, 255, 0, 0);
/* If we fail to allocate red... */
if (red == (-1)) {
/* Find the _closest_ color instead. */
red = gdImageColorClosest(im, 255, 0, 0);
}
/* Draw a dashed line from the upper left corner to the lower right corner */
gdImageDashedLine(im, 0, 0, 99, 99, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
int gdImageColorClosestHWB(gdImagePtr im, int r, int g, int b)
_(FUNCTION)_
gdImageColorClosestHWB searches the colors which have
been defined thus far in the image specified and returns
the index of the color with hue, whiteness and blackness
closest to the requested color. This scheme is typically
superior to the Euclidian distance scheme used by
gdImageColorClosest.
If no colors have yet been allocated in the image,
gdImageColorClosestHWB returns -1.
This function is most useful as a backup method for
choosing a drawing color when an image already contains
gdMaxColors (256) colors and no more can be allocated.
(This is not uncommon when working with existing PNG
files that already use many colors.) See
gdImageColorExact for a method of locating exact matches
only.
... inside a function ...
gdImagePtr im;
FILE *in;
int red;
/* Let's suppose that photo.png is a scanned photograph with
many colors. */
in = fopen("photo.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
/* Try to allocate red directly */
red = gdImageColorAllocate(im, 255, 0, 0);
/* If we fail to allocate red... */
if (red == (-1)) {
/* Find the _closest_ color instead. */
red = gdImageColorClosestHWB(im, 255, 0, 0);
}
/* Draw a dashed line from the upper left corner to the lower right corner */
gdImageDashedLine(im, 0, 0, 99, 99, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
int gdImageColorExact(gdImagePtr im, int r, int g, int b)
_(FUNCTION)_
gdImageColorExact searches the colors which have been
defined thus far in the image specified and returns the
index of the first color with RGB values which exactly
match those of the request. If no allocated color matches
the request precisely, gdImageColorExact returns -1. See
gdImageColorClosest for a way to find the color closest
to the color requested.
... inside a function ...
gdImagePtr im;
int red;
in = fopen("photo.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
/* The image may already contain red; if it does, we'll save a slot
in the color table by using that color. */
/* Try to allocate red directly */
red = gdImageColorExact(im, 255, 0, 0);
/* If red isn't already present... */
if (red == (-1)) {
/* Second best: try to allocate it directly. */
red = gdImageColorAllocate(im, 255, 0, 0);
/* Out of colors, so find the _closest_ color instead. */
red = gdImageColorClosest(im, 255, 0, 0);
}
/* Draw a dashed line from the upper left corner to the lower right corner */
gdImageDashedLine(im, 0, 0, 99, 99, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
int gdImageColorResolve(gdImagePtr im, int r, int g, int b)
_(FUNCTION)_
gdImageColorResolve searches the colors which have been
defined thus far in the image specified and returns the
index of the first color with RGB values which exactly
match those of the request. If no allocated color matches
the request precisely, then gdImageColorResolve tries to
allocate the exact color. If there is no space left in
the color table then gdImageColorResolve returns the
closest color (as in gdImageColorClosest). This function
always returns an index of a color.
... inside a function ...
gdImagePtr im;
int red;
in = fopen("photo.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
/* The image may already contain red; if it does, we'll save a slot
in the color table by using that color. */
/* Get index of red, or color closest to red */
red = gdImageColorResolve(im, 255, 0, 0);
/* Draw a dashed line from the upper left corner to the lower right corner */
gdImageDashedLine(im, 0, 0, 99, 99, red);
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
int gdImageColorsTotal(gdImagePtr im) _(MACRO)_
gdImageColorsTotal is a macro which returns the number of
colors currently allocated in the image. Use this macro
to obtain this information; do not access the structure
directly.
int gdImageColorRed(gdImagePtr im, int c) _(MACRO)_
gdImageColorRed is a macro which returns the red portion
of the specified color in the image. Use this macro to
obtain this information; do not access the structure
directly.
int gdImageColorGreen(gdImagePtr im, int c) _(MACRO)_
gdImageColorGreen is a macro which returns the green
portion of the specified color in the image. Use this
macro to obtain this information; do not access the
structure directly.
int gdImageColorBlue(gdImagePtr im, int c) _(MACRO)_
gdImageColorBlue is a macro which returns the green
portion of the specified color in the image. Use this
macro to obtain this information; do not access the
structure directly.
int gdImageGetInterlaced(gdImagePtr im) _(MACRO)_
gdImageGetInterlaced is a macro which returns true (1) if
the image is interlaced, false (0) if not. Use this macro
to obtain this information; do not access the structure
directly. See gdImageInterlace for a means of interlacing
images.
int gdImageGetTransparent(gdImagePtr im) _(MACRO)_
gdImageGetTransparent is a macro which returns the
current transparent color index in the image. If there is
no transparent color, gdImageGetTransparent returns -1.
Use this macro to obtain this information; do not access
the structure directly.
void gdImageColorDeallocate(gdImagePtr im, int color) _(FUNCTION)_
gdImageColorDeallocate marks the specified color as being
available for reuse. It does not attempt to determine
whether the color index is still in use in the image.
After a call to this function, the next call to
gdImageColorAllocate for the same image will set new RGB
values for that color index, changing the color of any
pixels which have that index as a result. If multiple
calls to gdImageColorDeallocate are made consecutively,
the lowest-numbered index among them will be reused by
the next gdImageColorAllocate call.
... inside a function ...
gdImagePtr im;
int red, blue;
in = fopen("photo.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
/* Look for red in the color table. */
red = gdImageColorExact(im, 255, 0, 0);
/* If red is present... */
if (red != (-1)) {
/* Deallocate it. */
gdImageColorDeallocate(im, red);
/* Allocate blue, reusing slot in table.
Existing red pixels will change color. */
blue = gdImageColorAllocate(im, 0, 0, 255);
}
/* ... Do something with the image, such as saving it to a file... */
/* Destroy it */
gdImageDestroy(im);
void gdImageColorTransparent(gdImagePtr im, int color)
_(FUNCTION)_
gdImageColorTransparent sets the transparent color index
for the specified image to the specified index. To
indicate that there should be _no_ transparent color,
invoke gdImageColorTransparent with a color index of -1.
Note that JPEG images do not support transparency, so
this setting has no effect when writing JPEG images.
The color index used should be an index allocated by
gdImageColorAllocate, whether explicitly invoked by your
code or implicitly invoked by loading an image. In order
to ensure that your image has a reasonable appearance
when viewed by users who do not have transparent
background capabilities (or when you are writing a
JPEG-format file, which does not support transparency),
be sure to give reasonable RGB values to the color you
allocate for use as a transparent color, _even though it
will be transparent on systems that support PNG
transparency_.
... inside a function ...
gdImagePtr im;
int black;
FILE *in, *out;
in = fopen("photo.png", "rb");
im = gdImageCreateFromPng(in);
fclose(in);
/* Look for black in the color table and make it transparent. */
black = gdImageColorExact(im, 0, 0, 0);
/* If black is present... */
if (black != (-1)) {
/* Make it transparent */
gdImageColorTransparent(im, black);
}
/* Save the newly-transparent image back to the file */
out = fopen("photo.png", "wb");
gdImagePng(im, out);
fclose(out);
/* Destroy it */
gdImageDestroy(im);
Copying and resizing functions
void gdImageCopy(gdImagePtr dst, gdImagePtr src, int dstX, int
dstY, int srcX, int srcY, int w, int h) _(FUNCTION)_
gdImageCopy is used to copy a rectangular portion of one
image to another image. (For a way of stretching or
shrinking the image in the process, see
gdImageCopyResized.)
The dst argument is the destination image to which the
region will be copied. The src argument is the source
image from which the region is copied. The dstX and dstY
arguments specify the point in the destination image to
which the region will be copied. The srcX and srcY
arguments specify the upper left corner of the region in
the source image. The w and h arguments specify the width
and height of the region.
When you copy a region from one location in an image to
another location in the same image, gdImageCopy will
perform as expected unless the regions overlap, in which
case the result is unpredictable.
_Important note on copying between images:_ since
different images do not necessarily have the same color
tables, pixels are not simply set to the same color index
values to copy them. gdImageCopy will attempt to find an
identical RGB value in the destination image for each
pixel in the copied portion of the source image by
invoking gdImageColorExact. If such a value is not found,
gdImageCopy will attempt to allocate colors as needed
using gdImageColorAllocate. If both of these methods
fail, gdImageCopy will invoke gdImageColorClosest to find
the color in the destination image which most closely
approximates the color of the pixel being copied.
... Inside a function ...
gdImagePtr im_in;
gdImagePtr im_out;
int x, y;
FILE *in;
FILE *out;
/* Load a small png to tile the larger one with */
in = fopen("small.png", "rb");
im_in = gdImageCreateFromPng(in);
fclose(in);
/* Make the output image four times as large on both axes */
im_out = gdImageCreate(im_in->sx * 4, im_in->sy * 4);
/* Now tile the larger image using the smaller one */
for (y = 0; (y < 4); y++) {
for (x = 0; (x < 4); x++) {
gdImageCopy(im_out, im_in,
x * im_in->sx, y * im_in->sy,
0, 0,
im_in->sx, im_in->sy);
}
}
out = fopen("tiled.png", "wb");
gdImagePng(im_out, out);
fclose(out);
gdImageDestroy(im_in);
gdImageDestroy(im_out);
void gdImageCopyResized(gdImagePtr dst, gdImagePtr src, int dstX,
int dstY, int srcX, int srcY, int destW, int destH, int
srcW, int srcH) _(FUNCTION)_
gdImageCopyResized is used to copy a rectangular portion
of one image to another image. The X and Y dimensions of
the original region and the destination region can vary,
resulting in stretching or shrinking of the region as
appropriate. (For a simpler version of this function
which does not deal with resizing, see gdImageCopy.)
The dst argument is the destination image to which the
region will be copied. The src argument is the source
image from which the region is copied. The dstX and dstY
arguments specify the point in the destination image to
which the region will be copied. The srcX and srcY
arguments specify the upper left corner of the region in
the source image. The dstW and dstH arguments specify the
width and height of the destination region. The srcW and
srcH arguments specify the width and height of the source
region and can differ from the destination size, allowing
a region to be scaled during the copying process.
When you copy a region from one location in an image to
another location in the same image, gdImageCopy will
perform as expected unless the regions overlap, in which
case the result is unpredictable. If this presents a
problem, create a scratch image in which to keep
intermediate results.
_Important note on copying between images:_ since images
do not necessarily have the same color tables, pixels are
not simply set to the same color index values to copy
them. gdImageCopy will attempt to find an identical RGB
value in the destination image for each pixel in the
copied portion of the source image by invoking
gdImageColorExact. If such a value is not found,
gdImageCopy will attempt to allocate colors as needed
using gdImageColorAllocate. If both of these methods
fail, gdImageCopy will invoke gdImageColorClosest to find
the color in the destination image which most closely
approximates the color of the pixel being copied.
... Inside a function ...
gdImagePtr im_in;
gdImagePtr im_out;
int x, y;
FILE *in;
FILE *out;
/* Load a small png to expand in the larger one */
in = fopen("small.png", "rb");
im_in = gdImageCreateFromPng(in);
fclose(in);
/* Make the output image four times as large on both axes */
im_out = gdImageCreate(im_in->sx * 4, im_in->sy * 4);
/* Now copy the smaller image, but four times larger */
gdImageCopyResized(im_out, im_in, 0, 0, 0, 0,
im_out->sx, im_out->sy,
im_in->sx, im_in->sy);
out = fopen("large.png", "wb");
gdImagePng(im_out, out);
fclose(out);
gdImageDestroy(im_in);
gdImageDestroy(im_out);
void gdImageCopyMerge(gdImagePtr dst, gdImagePtr src, int dstX,
int dstY, int srcX, int srcY, int w, int h, int pct)
_(FUNCTION)_
gdImageCopyMerge is almost identical to gdImageCopy,
except that it 'merges' the two images by an amount
specified in the last parameter. If the last parameter is
100, then it will function identically to gdImageCopy -
the source image replaces the pixels in the destination.
If, however, the _pct_ parameter is less than 100, then
the two images are merged. With pct = 0, no action is
taken.
This feature is most useful to 'highlight' sections of an
image by merging a solid color with pct = 50:
... Inside a function ...
gdImageCopyMerge(im_out, im_in, 100, 200, 0, 0, 30, 50, 50);
void gdImageCopyMergeGray(gdImagePtr dst, gdImagePtr src, int
dstX, int dstY, int srcX, int srcY, int w, int h, int
pct) _(FUNCTION)_
gdImageCopyMergeGray is almost identical to
gdImageCopyMerge, except that when merging images it
preserves the hue of the source by converting the
destination pixels to grey scale before the copy
operation.
... Inside a function ...
gdImageCopyMergeGray(im_out, im_in, 100, 200, 0, 0, 30, 50, 50);
void gdImagePaletteCopy(gdImagePtr dst, gdImagePtr src)
_(FUNCTION)_
Copies a palette from one image to another, attempting to
match the colors in the target image to the colors in the
source palette.
Miscellaneous Functions
int gdImageCompare(gdImagePtr im1, gdImagePtr im2)
_(FUNCTION)_
gdImageCompare returns a bitmap indicating if the
two images are different. The members of the bitmap
are defined in gd.h, but the most important is
GD_CMP_IMAGE, which indicated that the images will
actually appear different when displayed. Other,
less important, differences relate to pallette
entries. Any difference in the transparent colour
is assumed to make images display differently, even
if the transparent colour is not used.
... Inside a function ...
cmpMask = gdImageCompare(im1, im2);
gdImageInterlace(gdImagePtr im, int interlace) _(FUNCTION)_
gdImageInterlace is used to determine whether an
image should be stored in a linear fashion, in
which lines will appear on the display from first
to last, or in an interlaced fashion, in which the
image will "fade in" over several passes. By
default, images are not interlaced. (When writing
JPEG images, interlacing implies generating
progressive JPEG files, which are represented as a
series of scans of increasing quality.
Noninterlaced gd images result in regular
[sequential] JPEG data streams.)
A nonzero value for the interlace argument turns on
interlace; a zero value turns it off. Note that
interlace has no effect on other functions, and has
no meaning unless you save the image in PNG or JPEG
format; the gd and xbm formats do not support
interlace.
When a PNG is loaded with gdImageCreateFromPng or a
JPEG is loaded with gdImageCreateFromJpeg,
interlace will be set according to the setting in
the PNG or JPEG file.
Note that many PNG and JPEG viewers and web
browsers do _not_ support interlace or the
incremental display of progressive JPEGs. However,
the interlaced PNG or progressive JPEG should still
display; it will simply appear all at once, just as
other images do.
gdImagePtr im;
FILE *out;
/* ... Create or load the image... */
/* Now turn on interlace */
gdImageInterlace(im, 1);
/* And open an output file */
out = fopen("test.png", "wb");
/* And save the image -- could also use gdImageJpeg */
gdImagePng(im, out);
fclose(out);
gdImageDestroy(im);
gdFree(void *ptr) _(FUNCTION)_
gdFree provides a reliable way to free memory
allocated by functions such as gdImagePngPtr which
return blocks of memory. Use of this function
guarantees that the version of free() that is
ultimately called will be intended for use with the
version of malloc() that originally allocated the
block.
Constants
gdBrushed _(CONSTANT)_
Used in place of a color when invoking a
line-drawing function such as gdImageLine or
gdImageRectangle. When gdBrushed is used as
the color, the brush image set with
gdImageSetBrush is drawn in place of each
pixel of the line (the brush is usually
larger than one pixel, creating the effect of
a wide paintbrush). See also gdStyledBrushed
for a way to draw broken lines with a series
of distinct copies of an image.
gdMaxColors_(CONSTANT)_
The constant 256. This is the maximum number
of colors in a PNG file according to the PNG
standard, and is also the maximum number of
colors in a gd image.
gdStyled _(CONSTANT)_
Used in place of a color when invoking a
line-drawing function such as gdImageLine or
gdImageRectangle. When gdStyled is used as
the color, the colors of the pixels are drawn
successively from the style that has been set
with gdImageSetStyle. If the color of a pixel
is equal to gdTransparent, that pixel is not
altered. (This mechanism is completely
unrelated to the "transparent color" of the
image itself; see gdImageColorTransparent
gdImageColorTransparent for that mechanism.)
See also gdStyledBrushed.
gdStyledBrushed _(CONSTANT)_
Used in place of a color when invoking a
line-drawing function such as gdImageLine or
gdImageRectangle. When gdStyledBrushed is
used as the color, the brush image set with
gdImageSetBrush is drawn at each pixel of the
line, providing that the style set with
gdImageSetStyle contains a nonzero value (OR
gdTransparent, which does not equal zero but
is supported for consistency) for the current
pixel. (Pixels are drawn successively from
the style as the line is drawn, returning to
the beginning when the available pixels in
the style are exhausted.) Note that this
differs from the behavior of gdStyled, in
which the values in the style are used as
actual pixel colors, except for
gdTransparent.
gdDashSize _(CONSTANT)_
The length of a dash in a dashed line.
Defined to be 4 for backwards compatibility
with programs that use gdImageDashedLine. New
programs should use gdImageSetStyle and call
the standard gdImageLine function with the
special "color" gdStyled or gdStyledBrushed.
gdTiled _(CONSTANT)_
Used in place of a normal color in
gdImageFilledRectangle, gdImageFilledPolygon,
gdImageFill, and gdImageFillToBorder. gdTiled
selects a pixel from the tile image set with
gdImageSetTile in such a way as to ensure
that the filled area will be tiled with
copies of the tile image. See the discussions
of gdImageFill and gdImageFillToBorder for
special restrictions regarding those
functions.
gdTransparent _(CONSTANT)_
Used in place of a normal color in a style to
be set with gdImageSetStyle. gdTransparent is
_not_ the transparent color index of the
image; for that functionality please see
gdImageColorTransparent.
About the additional .gd image file format
In addition to reading and writing the PNG
and JPEG formats and reading the X Bitmap
format, gd has the capability to read and
write its own ".gd" format. This format is
_not_ intended for general purpose use and
should never be used to distribute images. It
is not a compressed format. Its purpose is
solely to allow very fast loading of images
your program needs often in order to build
other images for output. If you are
experiencing performance problems when
loading large, fixed PNG images your program
needs to produce its output images, you may
wish to examine the functions
gdImageCreateFromGd and gdImageGd, which read
and write .gd format images.
The program "pngtogd.c" is provided as a
simple way of converting .png files to .gd
format. I emphasize again that you will not
need to use this format unless you have a
need for high-speed loading of a few
frequently-used images in your program.
About the .gd2 image file format
In addition to reading and writing the PNG
format and reading the X Bitmap format, gd
has the capability to read and write its own
".gd2" format. This format is _not_ intended
for general purpose use and should never be
used to distribute images. It is a compressed
format allowing pseudo-random access to large
image files. Its purpose is solely to allow
very fast loading of _parts_ of images If you
are experiencing performance problems when
loading large, fixed PNG or JPEG images your
program needs to produce its output images,
you may wish to examine the functions
gdImageCreateFromGd2,
gdImageCreateFromGd2Part and gdImageGd2,
which read and write .gd2 format images.
The program "pngtogd2.c" is provided as a
simple way of converting .png files to .gd2
format.
About the gdIOCtx structure
Version 1.5 of GD added a new style of I/O
based on an IOCtx structure (the most
up-to-date version can be found in gd_io.h):
typedef struct gdIOCtx {
int (*getC)(struct gdIOCtx*);
int (*getBuf)(struct gdIOCtx*, void*, int);
void (*putC)(struct gdIOCtx*, int);
int (*putBuf)(struct gdIOCtx*, const void*, int);
int (*seek)(struct gdIOCtx*, const int);
long (*tell)(struct gdIOCtx*);
void (*free)(struct gdIOCtx*);
} gdIOCtx;
Most functions that accepted files in previous
versions now also have a counterpart that
accepts an I/O context. These functions have
a 'Ctx' suffix.
The Ctx routines use the function pointers in
the I/O context pointed to by gdIOCtx to
perform all I/O. Examples of how to implement
an I/O context can be found in io_file.c
(which provides a wrapper for file routines),
and io_dp.c (which implements in-memory
storage).
It is not necessary to implement all
functions in an I/O context if you know that
it will only be used in limited
cirsumstances. At the time of writing
(Version 1.6.1, July 1999), the known
requirements are:
All Must have 'free',
Anything that reads from the context Must
have 'getC' and 'getBuf',
Anything that writes to the context Must have
'putC' and 'putBuf'.
If gdCreateFromGd2Part is called Must also
have 'seek' and 'tell'.
If gdImageGd2 is called Must also have 'seek'
and 'tell'.
Please tell us you're using gd!
When you contact us and let us know you are
using gd, you help us justify the time spent
in maintaining and improving it. So please
let us know. If the results are publicly
visible on the web, a URL is a wonderful
thing to receive, but if it's not a publicly
visible project, a simple note is just as
welcome.
If you have problems
If you have any difficulties with gd, feel
free to contact the author, Thomas Boutell.
Problems relating to the gd2 format should be
addressed to Philip Warner.
_Be sure to read this manual carefully first.
_
Alphabetical quick index
gdBrushed | gdDashSize | gdFont | gdFontPtr |
gdFree | gdImage | gdImageArc | gdImageBlue |
gdImageBoundsSafe | gdImageChar |
gdImageCharUp | gdImageColorAllocate |
gdImageColorClosest | gdImageColorDeallocate
| gdImageColorExact | gdImageColorResolve |
gdImageColorTransparent | gdImageCopy |
gdImageCopyResized | gdImageCreate |
gdImageCreateFromGd | gdImageCreateFromGd2 |
gdImageCreateFromGd2Part |
gdImageCreateFromJpeg | gdImageCreateFromPng
| gdImageCreateFromPngSource |
gdImageCreateFromXbm | gdImageCreateFromXpm |
gdImageDashedLine | gdImageDestroy |
gdImageFill | gdImageFillToBorder |
gdImageFilledRectangle | gdImageGd |
gdImageGd2 | gdImageGetInterlaced |
gdImageGetPixel | gdImageGetTransparent |
gdImageGreen | gdImageInterlace | gdImageJpeg
| gdImageLine | gdImageFilledPolygon |
gdImagePaletteCopy | gdImagePng |
gdImagePngToSink | gdImagePolygon |
gdImagePtr | gdImageWBMP | gdImageRectangle |
gdImageRed | gdImageSetBrush |
gdImageSetPixel | gdImageSetStyle |
gdImageSetTile | gdImageString |
gdImageString16 | gdImageStringFT |
gdImageStringTTF | gdImageStringUp |
gdImageStringUp16 | gdImageWBMP | gdMaxColors
| gdPoint | gdStyled | gdStyledBrushed |
gdTiled | gdTransparent
_Boutell.Com, Inc._
