<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
<head>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1">
<meta name="GENERATOR" content="Microsoft FrontPage 2.0">
<title>XV: The Control Window, part 4/6</title>
<meta name="FORMATTER" content="Microsoft FrontPage 2.0">
</head>
<body background="images/blutxtr2.jpg" bgcolor="#ABABD6">
<p>
<a href="http://www.trilon.com/xv">
<img src="images/small_banner.gif" width="630" height="25" border="0"></a>
</p>
<h2><a name="cropping-commands">Cropping Commands</a></h2>
<dl>
<dt><a name="crop"><img src="images/fig-064.gif" width="72"
height="25"></a></dt>
<dd>Crops the image to the current selection rectangle. This
command is only available when a cropping rectangle has
been drawn on the image. See "<a
href="image-window.html#cropping">Cropping</a>" for
further information.<br>
Keyboard Equivalent: <b>c</b> </dd>
<dt> </dt>
<dt><a name="uncrop"><img src="images/fig-065.gif" width="72"
height="25"></a></dt>
<dd>Returns the image to its normal, uncropped state. This
command is only available after the image has been
cropped. See "<a href="image-window.html#cropping">Cropping</a>"
for further information.<br>
Keyboard Equivalent: <b>u</b> </dd>
<dt> </dt>
<dt><a name="autocrop"><img src="images/fig-066.gif"
width="72" height="25"></a></dt>
<dd>Crops off any constant-color borders that exist in the
image. It will crop to the smallest rectangle that
encloses the 'interesting' section of the image. It may
not always appear to work because of minor invisible
color changes in the image. As such, it works best on
computer-generated images, and not as well on scanned
images. In an attempt to get around this problem, if you <b>AutoCrop</b>
while in <b>24-bit Mode</b> , it will crop off portions
that change by a little bit, not just portions that are
exactly the same. Not that it works all that well.<br>
Keyboard Equivalent: <b>C</b> </dd>
</dl>
<p>Also, you can 'fine-crop' an image, by holding the <b><Ctrl></b>
key and pressing the arrow keys on your keyboard. Each press of
the keys will remove one row (or column) of pixels from the
appropriate edge. For example, pressing <b><Ctrl><Up></b>
will crop off the bottom row of the image. Likewise, <b><Ctrl><Down></b>
will crop off the top row, <b><Ctrl><Left> </b>will
crop off the right edge, and <b><Ctrl><Right></b>
will crop off the left edge. It may sound backwards, but it does
the Right Thing. </p>
<p>This 'fine-cropping' will work regardless of whether or not
there is a selection rectangle currently drawn. If you
accidentally crop too much off the image, you can use the <b>UnCrop</b>
command described above to get the original image back.</p>
<p>Note that cropping never actually changes the image, only what
portions are displayed. The original image can always be restored
using the <b>UnCrop</b> command. Also, note that the 'cropping'
commands and the 'zoom' commands (See "<a
href="image-window.html#zooming">Zooming</a>" ) are related,
in that both affect the 'visible portion' of the image. The
cropping commands maintain the same expansion factors by making
the window larger or smaller, while the zooming commands maintain
the same window size, and stretch the relevant portion of the
image to fit. As such, the <b>UnCrop</b> command will also undo
an zooming that you may have done.</p>
<h2><a name="cut-paste-commands">Image Cut and Paste Commands</a></h2>
<p>A new feature added to Version 3.10 is the ability to cut and
paste arbitrary rectangular portions of images. You can cut (and
copy) and paste within a single image, between two different
images, or even between two running copies of <i>xv.</i> You can
even cut or copy a portion of an image, exit <i>xv</i>, go out
for dinner, come back, restart <i>xv</i> , and paste the
previously-copied portion into the current image.</p>
<p>Copied image data is normally stored within the X Server's
memory (in the '<tt>XV_CLIPBOARD</tt>' property), and remains
there until some other data is copied, or until the X Server is
reset (i.e., when you log off). This allows you to transfer image
data between different copies of <i>xv</i>, and the <i>xv</i>'s
can even be running on different machines.</p>
<p>If there is not enough server memory available to hold the
copied image data (this can happen if you copy a large amount of
data, and you're using an X Terminal, as opposed to a
workstation), <i>xv</i> will detect this, and fall back to using
a file ('<tt>.xvclip</tt>') in your home directory. Needless to
say, this precludes transferring data between <i>xv</i>'s running
on different machines, but it's better than nothing. </p>
<dl>
<dt><a name="copy"><img src="images/fig-067.gif" width="36"
height="25"></a></dt>
<dd><b>Copy</b> . First, you must select a region to copy,
via the selection rectangle mechanism (See "<a
href="image-window.html#selection-rectangle">Selection
Rectangle</a>" ). Then, use this command to copy the
selected data to the 'clipboard'.<br>
Keyboard Equivalent: <b><Meta> c</b></dd>
<dt> </dt>
<dt><a name="cut"><img src="images/fig-068.gif" width="36"
height="25"></a></dt>
<dd><b>Cut</b> . Operates just like the <b>Copy</b> command,
except that it also clears the selection to the 'current
color', which is set using the pixel measurement tool.
See "<a
href="image-window.html#displaying-pixel-values">Displaying
Pixel Values</a>" for further information.<br>
Keyboard Equivalent: <b><Meta> x</b></dd>
<dt> </dt>
<dt><a name="paste"><img src="images/fig-069.gif" width="36"
height="25"></a></dt>
<dd><b>Paste</b> . If there is no selection rectangle
currently drawn, the first time you issue the <b>Paste</b>
command, it will create a selection rectangle the size
and shape of the image data that will be pasted. You may
move and resize this rectangle as you see fit (See "<a
href="image-window.html#selection-rectangle">Selection
Rectangle</a>" ). Then, when you have the selection
appropriately adjusted, hit <b>Paste</b> a second time to
actually paste the clipboard contents onto the image. <p>On
the other hand, if you have a selection rectangle drawn
when you hit <b>Paste</b> the first time, the image will
be pasted into the selected area immediately.<br>
Keyboard Equivalent: <b><Meta> v</b> </p>
</dd>
<dt><a name="clear"><img src="images/fig-070.gif" width="36"
height="25"></a></dt>
<dd><b>Clear</b> . Clears the selected region to the 'current
color', which is set using the pixel measurement tool.
See "<a
href="image-window.html#displaying-pixel-values">Displaying
Pixel Values</a>" .<br>
Keyboard Equivalent: <b><Meta> d</b> </dd>
</dl>
<h2><a name="pad-command">The Pad Command</a></h2>
<p>The <b>Pad</b> command is the opposite of the <b>Crop</b>
command. Sort of. It lets you add a border of a specified size to
the edges of the image. It also lets you resize images to some
desired size without manually expanding or cropping the image.
But it goes further than that. There are a whole slew of
interesting effects available, as described below:</p>
<dl>
<dt><a name="pad"><img src="images/fig-071.gif" width="36"
height="25"></a></dt>
<dd><b>Pad</b> . Brings up the dialog box shown below.<br>
Keyboard Equivalent: <b>P</b></dd>
</dl>
<p><a name="pad-window"><img src="images/fig-072.gif" width="494"
height="245"> </a></p>
<h3><a name="pad-methods">Pad Methods</a></h3>
<table border="0" cellpadding="4">
<tr>
<td valign="top"><a name="pad-method-menu"><img
src="images/fig-074.gif" width="145" height="52"></a></td>
<td>There are three primary <b>Pad</b> methods, as shown
to the left. These methods are accessible via the 'Pad
Method' menu, which says 'Solid Fill' in the dialog box
shown above. In all cases, the <b>Pad</b> command
operates in the same basic way: A new image of the
desired size is created, it is filled as specified, and
the original image is pasted onto this new image,
centered. If the new image is smaller than the original
image, the original image will be cropped. Otherwise, the
area outside the original image will have the new
background.</td>
</tr>
</table>
<p>Note: The new, padded image will have the same 8/24-bit mode
as the original. As such, you <i>probably</i> want to switch to <b>24-bit
Mode</b> <i>before</i> issuing the <b>Pad</b> command,
particularly if you intend to modify the image further. (See
"<a href="control-window-3.html#bit-menu">The 24/8 Bit Menu</a>"
.)</p>
<p>The 'Pad Method' menu gives you three different ways of
filling the background:</p>
<dl>
<dt><a name="solid-fill"><img src="images/fig-073.gif"
width="141" height="16"></a></dt>
<dd>The background is filled with a solid color. The color
may be specified by name, (as specified in the X11 ' <tt>rgb.txt</tt>
' file), by RGB values in the range 0- 255, separated by
commas (e.g. '0,255,128'), or by RGB values in
hexadecimal (e.g. '0x00ff80'). In each case, the string
you enter is parsed, and the background is filled solid
with the specified color. </dd>
<dt> </dt>
<dt><a name="run-bggen"><img src="images/fig-075.gif"
width="141" height="16"></a></dt>
<dd>The external program <i>bggen</i> is executed to generate
the background. This program is normally distributed with
<i>xv</i>, and <i>xv</i> assumes that the executable is
located somewhere in your search path (such as ' <tt>/usr/local/bin/bggen</tt>
'). <i>bggen</i> can generate background gradients, at a
specified angle. The gradient can be the entire size of
the background, or it can repeat multiple times. See
"<a href="external-programs.html">External Programs</a>"
for a complete description of the <i>bggen</i> command. </dd>
<dt> </dt>
<dt><a name="load-image"><img src="images/fig-076.gif"
width="141" height="16"></a></dt>
<dd>An image file in any of the <i>xv</i>-supported formats
may be loaded and used as the background. In this case,
the background size (and therefore the size of the padded
image) is equal to the size of the loaded background
image. If you want a different size, you can load the
background image (as a regular image), resize it as you
see fit, save it, and use the newly saved version as the
background for the original image. </dd>
</dl>
<h3><a name="size-dials">Image Size Dials</a></h3>
<table border="0" cellpadding="4" cellspacing="4">
<tr>
<td valign="top"><img src="images/fig-077.gif"
width="157" height="123"></td>
<td valign="top">These dials let you specify the size of
the new, padded image in the "Solid" and
"Run 'bggen'" modes. In the "Load
Image" mode, the dials are disabled, as the new
image size is dictated by the size of the loaded image.<p>If
the image size dials are enabled, the small button above
them resets them to the size of the currently-loaded
image. Note that padding with the 'new' size equal to the
current size won't actually <i>do</i> anything, unless
you change the "Opaque" dial, described below.</p>
</td>
</tr>
</table>
<h3><a name="opaque-ness">Opaque-ness</a></h3>
<table border="0" cellpadding="4" cellspacing="4">
<tr>
<td valign="top"><img src="images/fig-078.gif" width="81"
height="123"></td>
<td valign="top">This dial sets the 'opaque-itude' of the
foreground (the original image). Normally, this is set to
'100%', which simply means that everywhere the original
image and the background overlap, the original image is
what you'll see. If you set the dial to '0%', then
wherever the original image and the background overlap,
the background is what you'll see. In any case, at points
where the foreground image does <i>not</i> overlap the
background, you'll see the background, unmodified.
(Practical upshot: at '0%' you will <i>only</i> see the
background.)</td>
</tr>
</table>
<p>Of course, most of the interesting effects happen when the
dial is set to intermediate values, where the foreground image
will appear semi-transparent.</p>
<p>There are four modes the 'Opaque' dial can operate in. They
are selected by clicking the button located above the 'Opaque'
dial.</p>
<h4><a name="rgb">RGB</a></h4>
<p>The two images are blended together in the most obvious way.
Each RGB color component in the new image is computed by taking a
weighted average of the RGB components from the appropriate
pixels in the foreground and background images. Like so:</p>
<dl>
<dd><i>R</i> <i>new</i> <i>= </i>( <i>opaque%</i> * <i>R</i> <i>fg</i>
) + ( (100 - <i>opaque%</i> ) * <i>R</i> <i>bg</i> ) <i>(same
for G and B)</i> </dd>
</dl>
<h4><a name="int">INT</a></h4>
<p>On overlapping pixels, only the <i>Intensity</i> components
(the 'V' in the HSV colorspace, see "<a
href="rgb-hsv-colorspaces.html">RGB & HSV Colorspaces</a>"
) of the pixels are blended, using the same weighted average
calculation shown above. If you set the 'Opaque' value to '0%',
brightness of overlapping pixels will be completely determined by
the 'background' pixel. It's possible to get some interesting
'masking' effects and whatnot by playing around with
black&white backgrounds.</p>
<h4><a name="sat">SAT</a></h4>
<p>Similar to <b>INT</b>, except that it is the <i>Saturation</i>
component (the 'S' in the HSV colorspace, see "<a
href="rgb-hsv-colorspaces.html">RGB & HSV Colorspaces</a>"
) of the two pixels that will be blended together, again using
the weighted average calculation. The effects possible with this
one are considerably more subtle, and not necessarily
interesting. It is mainly included for completeness.</p>
<h4><a name="hue">HUE</a></h4>
<p>In this case, the colors of the two overlapping pixels are
blended. You can get some interesting effects by setting 'Opaque'
to '0%', and loading a colorful rainbow background. In this case,
at all overlapping pixels, it will be as if the foreground image
were a greyscale transparency, as the brightness and saturation
will be controlled by the foreground, and the color will be
controlled by the background.</p>
<p>Technical Note: The <b>HUE</b> case does <i>not</i> simply do
a weighted average of the two hue components. Instead, it plots
the two points on the edge of a standard color wheel, draws a
straight line between them, and picks a point along this line
based on the 'Opaque' value (i.e., the larger the value, the
closer it is to the 'foreground' endpoint of the line). As a
result, the <b>HUE</b> setting can affect <i>both</i> the hue and
saturation components of the computed pixel. While this makes
this 'Opaque' mode somewhat unlike the others, once again it is a
fine example of xv's trademark "Do The Right Thing"
technology.</p>
<hr color="#000080">
<p>
<MAP NAME="FrontPageMap">
<AREA SHAPE="RECT" COORDS="393, 0, 453, 24" HREF="control-window-5.html">
<AREA SHAPE="RECT" COORDS="331, 0, 387, 24" HREF="control-window-3.html">
<AREA SHAPE="RECT" COORDS="263, 0, 323, 24" HREF="manindex.html">
<AREA SHAPE="RECT" COORDS="164, 0, 254, 24" HREF="index.html#Table+of+Contents">
</MAP>
<img src="images/navbar.gif" width="630" ismap usemap="#FrontPageMap"
height="25" border="0">
</p>
</body>
</html>
distrib
>
Mageia
>
6
>
armv7hl
>
media
>
nonfree-release
>
by-pkgid
>
7faca9fe811014ac5ad05a93b36da3c0
>
files
>
29
