<!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 Color Editor, part 3/3</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="rgb-modification-tool">The RGB Modification Tool</a></h2>
<table border="0" cellpadding="4" cellspacing="4">
<tr>
<td><img src="images/fig-126.gif" width="187"
height="502"></td>
<td>The <i>RGB Modification</i> tool is a collection of
three graph windows, each of which operate on one of the
components of the RGB colorspace. This tool lets you
perform global color-correction on the image by boosting
or cutting the values of one or more of the RGB color
components. You can use this to correct for color screens
that are 'too blue', or for color printers that produce
'brownish' output, or whatever.<p>The graphs work exactly
as explained in "<a
href="color-editor-2.html#intensity-graph">The Intensity
Graph"</a> .</p>
<p>Neat Trick: In addition to color-correction, you can
use the RGB modification tool to add color to images that
didn't have color to begin with. For instance, you can
'pseudo-color' a greyscale image.</p>
</td>
</tr>
</table>
<p>An example of pseudo-coloring:</p>
<ol>
<li>Adjust the <i>Red</i> graph so that there is a strong red
presence on the right side of the graph, and none on the
left, or in the middle.</li>
<li>Adjust the <i>Green</i> graph so that there is a strong
green presence in the middle of the graph, and none on
the left or right.</li>
<li>Adjust the <i>Blue</i> graph so that there is a strong
blue presence on the left side of the graph, and none on
the left, or in the middle.</li>
<li>The graphs should look roughly like this:<br>
<img src="images/fig-123.gif" width="167" height="149"> <img
src="images/fig-124.gif" width="167" height="149"> <img
src="images/fig-125.gif" width="167" height="149"> </li>
</ol>
<p>You now have a transformation that will take greyscale images
and display them in pseudo-color, using a 'temperature' color
scheme. Neato! </p>
<h2><a name="color-editor-controls">The Color Editor Controls</a></h2>
<table border="0" cellpadding="4" cellspacing="4">
<tr>
<td valign="top"><img src="images/fig-133.gif"
width="212" height="97"></td>
<td valign="top">These buttons provide general control
over the whole <i>xv color editor</i> window. You can
display the image with or without color modification,
save and recall presets, and undo/redo changes. Also,
convenience controls are given for performing some of the
most common operations on the Intensity graph.</td>
</tr>
</table>
<dl>
<dt><a name="apply"><img src="images/fig-127.gif" width="53"
height="24"></a></dt>
<dd>Displays the image using the current HSV and RGB
Modifications. Also turns the '<b>Display with HSV/RGB
mods</b>' checkbox on. (See below.) This is only useful
when the '<b>Auto-apply HSV/RGB mods</b>' checkbox is
off.<br>
Keyboard Equivalent: <b><Meta> a </b></dd>
<dt> </dt>
<dt><a name="nomod"><img src="images/fig-128.gif" width="53"
height="24"></a></dt>
<dd>Displays the image without any HSV or RGB Modifications.
Also turns the '<b>Display with HSV/RGB mods</b>'
checkbox off. </dd>
<dt> </dt>
<dt><a name="undo"><img src="images/fig-129.gif" width="53"
height="24"></a></dt>
<dd>Undoes the last change to the HSV or RGB controls. <p>It
may be helpful to think of <i>xv</i> as maintaining a
series of 32 'snapshots' of the HSV and RGB controls. You
are normally looking at the last frame in this series.
The <b>Undo</b> control moves you backwards in the
series. </p>
</dd>
<dt><a name="redo"><img src="images/fig-130.gif" width="53"
height="24"></a></dt>
<dd>Only available after you've hit <b>Undo</b> . Moves you
forward in the 'snapshot' series described above. Note
that if you have hit <b>Undo</b> a few times (i.e.,
you're now looking at some frame in the middle of the
series), and you change an HSV or RGB control, all
subsequent frames in the series are thrown away, and the
current state becomes that last frame in the series. </dd>
<dt> </dt>
<dt><a name="reset"><img src="images/fig-131.gif" width="53"
height="24"></a></dt>
<dd>Resets all HSV and RGB controls to their default
settings. Doesn't affect the <b>Colormap Editing</b>
tool. Note that these default settings can be changed
using the <b>Set</b> command described below.<br>
Keyboard Equivalents: <b>R</b> , <b><Meta> r</b> ,
and <b><Meta> 0 </b></dd>
<dt> </dt>
<dt><a name="color-editor-presets"><img
src="images/fig-132.gif" width="53" height="48"></a></dt>
<dd>Pressing any of these buttons recalls a preset (a
complete set of values for the HSV and RGB controls). By
default, the presets are: <ol>
<li>Binary intensity. Every color in the image is
either at full brightness, or black. Gives images
a neat 'neon' sort of look, much like the <i>Saturday
Night Live</i> credits of the late-70's.</li>
<li>Binary colors. The image will be shown using only
the 8 binary combinations of red, green, and
blue. (e.g. black, blue, green, cyan, red,
magenta, yellow, white) </li>
<li>Temperature pseudo-color. (For use on greyscale
images) Maps intensity values 0-255 into a
'temperature' color scheme where blue is
'coldest' and red is 'hottest'.</li>
<li>Map pseudo-color. (For use on greyscale images)
Maps intensity values 0- 255 into something akin
to the standard 'elevation map' color scheme
(blue, green, yellow, brown)</li>
</ol>
<p>Of course, you can replace these defaults with your
own. See "<a
href="modifying-behavior-4.html#color-editor-resources">Modifying
<em>xv</em> Behavior</a>" for more details.<br>
Keyboard Equivalents: <b><Meta> 1</b> , <b><Meta>
2</b> , <b><Meta> 3</b> , and <b><Meta> 4 </b></p>
</dd>
<dt><a name="set"><img src="images/fig-134.gif" width="53"
height="24"></a></dt>
<dd>Used in conjunction with the <b>Reset</b>, <b>1</b>, <b>2</b>,
<b>3</b>, or <b>4</b> buttons to store the current
settings of the HSV and RGB controls into a preset. To do
so, press the <b>Set</b> button, and then press one of
the <b>Reset</b>, <b>1</b>, <b>2</b>, <b>3</b>, or <b>4</b>
buttons. The current HSV and RGB control settings will be
stored in that preset, as long as <i>xv</i> continues
running. The values will be lost when the program exits.
It is also possible to save these values permanently. See
the <b>CutRes</b> button (below) and "<a
href="modifying-behavior-4.html#color-editor-resources">Modifying
<em>xv</em> Behavior</a>" for more details. </dd>
<dt> </dt>
<dt><a name="cutres"><img src="images/fig-135.gif" width="53"
height="24"></a></dt>
<dd>Copies the current settings of the HSV and RGB controls,
as text, into the X server's cut buffer. You can then use
a text editor to paste these values into your '<tt>.Xdefaults</tt>'
(or '<tt>.Xresources</tt>') file. This lets you save the
current settings 'permanently'. See "<a
href="modifying-behavior-4.html#color-editor-resources">Modifying
<em>xv</em> Behavior</a>" for more details. </dd>
<dt> </dt>
<dt><a name="close"><img src="images/fig-136.gif" width="53"
height="24"></a></dt>
<dd>This button closes the <i>xv color editor</i> window. </dd>
<dt> </dt>
<dt><a name="brite"><img src="images/fig-137.gif" width="53"
height="24"></a></dt>
<dd>Brightens the image by moving all the handles in the <i>Intensity</i>
graph up by a constant amount. </dd>
<dt> </dt>
<dt><a name="dim"><img src="images/fig-138.gif" width="53"
height="24"></a></dt>
<dd>Darkens the image by moving all the handles in the <i>Intensity</i>
graph down by a constant amount. </dd>
<dt> </dt>
<dt><a name="sharp"><img src="images/fig-139.gif" width="53"
height="24"></a></dt>
<dd>Increases the contrast of the image by moving handles on
the left side of the <i>Intensity</i> graph down, and
handles on the right side up. </dd>
<dt> </dt>
<dt><a name="dull"><img src="images/fig-140.gif" width="53"
height="24"></a></dt>
<dd>Decreases the contrast of the image by moving handles on
the left side of the <i>Intensity</i> graph up, and
handles on the right side down. </dd>
<dt> </dt>
<dt><a name="norm"><img src="images/fig-141.gif" width="53"
height="24"></a></dt>
<dd>Normalizes the image so that the darkest pixels in the
image are given an intensity of '0', and the brightest
pixels are given an intensity of '255'. Intermediate
colors are interpolated accordingly. This forces the
image to have the full (maximum) dynamic range.<br>
Keyboard Equivalent: <b>N</b> </dd>
<dt> </dt>
<dt><a name="histeq"><img src="images/fig-142.gif" width="53"
height="24"></a></dt>
<dd>Runs a histogram equalization algorithm on the currently
displayed region of the image. That is, if you're
cropped, it will only run the algorithm on the cropped
section. Note, however, that the only modification it
makes to the image is to generate a bizarre corrective <i>Intensity</i>
curve. As such, if you <b>HistEq</b> a section of the
image, the rest of the image will probably not be what
you'd want. Also note that the histogram curve will 'go
away' if you touch any of the handles in the <i>Intensity</i>
graph window, just like a 'gamma' curve would.<br>
Keyboard Equivalent: <b>H</b> </dd>
<dt> </dt>
<dt><a name="display-with-mods"><img src="images/fig-143.gif"
width="208" height="17"></a></dt>
<dd>The '<b>Display with HSV/RGB mods</b>' checkbox tells you
whether or you're looking at a modified image (checked)
or the 'raw', unmodified image (unchecked). The <b>Apply</b>
and <b>NoMod</b> buttons change the setting of this
checkbox, and you can also change the checkbox directly
by clicking on it. </dd>
<dt> </dt>
<dt><a name="auto-apply-hsv"><img src="images/fig-144.gif"
width="208" height="17"></a></dt>
<dd>The '<b>Auto-apply HSV/RGB mods</b>' checkbox controls
whether or not the program regenerates and redisplays the
image after each change to an HSV or RGB control. By
default, this checkbox is turned on, so that you can
easily see the results of your modifications. However, if
you want to make a large number of changes at once, it
might be preferable to turn automatic redisplay off for a
while, to speed things up. </dd>
<dt> </dt>
<dt><a name="auto-apply-drag"><img src="images/fig-145.gif"
width="208" height="17"></a></dt>
<dd>The '<b>Auto-apply while dragging</b>' checkbox controls
whether or not the image colors are changed automatically
as you manipulate the various <i>xv color editor</i>
dials and graphs. This button is normally turned on, but
for it to have any effect, you must be in '<b>Read/Write
Colors</b>' mode. See "<a
href="control-window-2.html#color-allocation-commands">Color
Allocation Commands</a>" and the '<tt>-rw</tt>' mode
described in "<a
href="modifying-behavior-1.html#color-allocation-options">Color
Allocation Options</a>" for more information. </dd>
<dt> </dt>
<dt><a name="auto-reset"><img src="images/fig-146.gif"
width="208" height="17"></a></dt>
<dd>The '<b>Auto-reset on new image</b>' checkbox controls
whether or not the HSV and RGB controls are <b>Reset</b>
back to their default values whenever a new image is
loaded up. By default, this is also turned on, as when
you're playing with the HSV/RGB controls, you probably
only want to affect the current image, and not all
subsequently loaded images as well. </dd>
</dl>
<hr color="#000080">
<p>
<MAP NAME="FrontPageMap">
<AREA SHAPE="RECT" COORDS="393, 0, 453, 24" HREF="visual-schnauzer-1.html">
<AREA SHAPE="RECT" COORDS="331, 0, 387, 24" HREF="color-editor-2.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
>
24
