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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta name="generator" content=
"HTML Tidy for Linux/x86 (vers 7 December 2008), see www.w3.org" />
<title>RMagick 0.0.0: Constants</title>
<meta http-equiv="Content-Type" content=
"text/html; charset=us-ascii" />
<meta name="GENERATOR" content="Quanta Plus" />
<meta name="Copyright" content=
"Copyright (C) 2006 by Timothy P. Hunter" />
<link rel="stylesheet" type="text/css" href="css/doc.css" />
<script type="text/javascript" src="scripts/doc.js">
</script>
<style type="text/css">
/*<![CDATA[*/
/* Styles local to this page. */
dl, p {
margin-left: 100px;
margin-right:100px;
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dt {
font-family: monospace;
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/*
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h3.const {
background-color: #c0c0c0;
color: #000;
padding-left: 5px;
margin-top: 2em;
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/*
* Modify .simple_table for the QuantumRange/QuantumDepth table.
* The major differences are the centered text and the auto width.
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border: thin solid black;
background-color: #f8f8f8;
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</head>
<body>
<h6 id="header">RMagick 0.0.0 User's Guide and Reference</h6>
<div class="nav">
« <a href="info.html">Prev</a> | <a href=
"index.html">Contents</a> | <a href=
"rvgtut.html">Next</a> »
</div>
<h1>Constants</h1>
<div id="toc">
<h2>Table of Contents</h2>
<h3>Constants</h3>
<div class="toccol">
<ul>
<li><a href="#Miscellaneous_constants">Miscellaneous
constants</a></li>
<li><a href="#AlignType">AlignType</a></li>
<li><a href="#ChannelType">ChannelType</a></li>
<li><a href="#ClassType">ClassType</a></li>
<li><a href="#ColorspaceType">ColorspaceType</a></li>
<li><a href="#ComplianceType">ComplianceType</a></li>
<li><a href="#CompositeOperator">CompositeOperator</a></li>
<li><a href="#CompressionType">CompressionType</a></li>
<li><a href="#DecorationType">DecorationType</a></li>
</ul>
</div>
<div class="toccol">
<ul>
<li><a href="#DisposeType">DisposeType</a></li>
<li><a href="#DitherMethod">DitherMethod</a></li>
<li><a href="#EndianType">EndianType</a></li>
<li><a href="#FilterTypes">FilterTypes</a></li>
<li><a href="#GravityType">GravityType</a></li>
<li><a href="#ImageType">ImageType</a></li>
<li><a href="#InterlaceType">InterlaceType</a></li>
<li><a href=
"#InterpolatePixelMethod">InterpolatePixelMethod</a></li>
<li><a href="#MetricType">MetricType</a></li>
</ul>
</div>
<div class="toccol">
<ul>
<li><a href="#NoiseType">NoiseType</a></li>
<li><a href="#Opacity">Opacity</a></li>
<li><a href="#OrientationType">OrientationType</a></li>
<li><a href="#PaintMethod">PaintMethod</a></li>
<li><a href="#RenderingIntent">RenderingIntent</a></li>
<li><a href="#ResolutionType">ResolutionType</a></li>
<li><a href="#StretchType">StretchType</a></li>
<li><a href="#StorageType">StorageType</a></li>
<li><a href="#StyleType">StyleType</a></li>
<li><a href="#WeightType">WeightType</a></li>
</ul>
</div>
</div>
<h2 class="methods">Constants</h2>
<h3 class="const" style="margin-top:0" id=
"Miscellaneous_constants">Miscellaneous constants</h3>
<dl>
<dt>Long_version</dt>
<dd>An extended form of the <code>Version</code> constant with
the format shown here:<br />
<code>This is RMagick 2.0.0 ($Date: 2009/09/05 20:10:15 $)
Copyright (C) 2008 by Timothy P. Hunter<br />
Built with ImageMagick 6.3.7 01/05/08 Q16
http://www.imagemagick.org<br />
Built for ruby 1.8.6<br />
Web page: http://rmagick.rubyforge.org<br />
Email: rmagick@rubyforge.org</code></dd>
<dt>Magick_version</dt>
<dd>The ImageMagick version string. This has the form:<br />
<code>@(#)ImageMagick X.Y.Z MM/DD/YY Q:16
http://www.imagemagick.org</code></dd>
<dt>MANAGED_MEMORY</dt>
<dd>
If <code>true</code>, RMagick is using Ruby managed memory
for all allocations. If <code>false</code>, RMagick allocates
memory for objects directly from the operating system. You
can enable RMagick to use Ruby managed memory (when built
with ImageMagick 6.4.0-11 and later) by setting
<pre>
RMAGICK_ENABLE_MANAGED_MEMORY = true
</pre><em>before</em> requiring RMagick.
</dd>
<dt>QuantumRange</dt>
<dd>The maximum value of a <em>Quantum</em>. A quantum is one
of the red, green, blue, or opacity elements of a pixel in the
RGB colorspace, or cyan, yellow, magenta, or black elements in
the CYMK colorspace.</dd>
<dt>MaxRGB <i>(deprecated)</i></dt>
<dd>Same as QuantumRange.</dd>
<dt>QuantumDepth</dt>
<dd>
The number of bits in a quantum. The relationship between
QuantumDepth and QuantumRange is summarized in this table.
<table summary="number of bits in a quantum" id="maxrgb">
<tr>
<th>QuantumDepth</th>
<th>QuantumRange</th>
</tr>
<tr>
<td>8</td>
<td>255</td>
</tr>
<tr>
<td>16</td>
<td>65535</td>
</tr>
<tr>
<td>32</td>
<td>4294967295</td>
</tr>
</table>
</dd>
<dt>Version</dt>
<dd>The RMagick version string. This has the form:<br />
<code>RMagick 2.0.0</code></dd>
</dl>
<h3 class="const" id="AlignType">AlignType</h3>
<p>Specify text alignment. See <a href=
"draw.html#Draw.align_eq">align=</a>, <a href=
"draw.html#Draw.text_align">text_align</a>.</p>
<dl>
<dt>UndefinedAlign</dt>
<dd>No alignment specified. Equivalent to LeftAlign.</dd>
<dt>LeftAlign</dt>
<dd>Align the leftmost part of the text to the starting
point.</dd>
<dt>CenterAlign</dt>
<dd>Center the text around the starting point.</dd>
<dt>RightAlign</dt>
<dd>Align the rightmost part of the text to the starting
point.</dd>
</dl>
<h3 class="const" id="ChannelType">ChannelType</h3>
<p>Specify an image channel. A channel is a color component of a
pixel. In the RGB colorspace the channels are red, green, and
blue. There may also be an alpha (transparency/opacity) channel.
In the CMYK colorspace the channels area cyan, magenta, yellow,
and black. In the HSL colorspace the channels are hue,
saturation, and lightness. In the Gray colorspace the only
channel is gray. See <a href=
"image1.html#channel">Image#channel</a> and <a href=
"info.html#channel">Image::Info#channel=</a>.</p>
<dl>
<dt>UndefinedChannel</dt>
<dt>RedChannel</dt>
<dt>GreenChannel</dt>
<dt>BlueChannel</dt>
<dt>CyanChannel</dt>
<dt>MagentaChannel</dt>
<dt>YellowChannel</dt>
<dt>BlackChannel</dt>
<dt>OpacityChannel</dt>
<dt>AllChannels</dt>
<dd>In the RGB colorspace, the red, blue, green, and alpha
channels. In the CMYK colorspace, the cyan, magenta, yellow,
and black channels.</dd>
<dt>GrayChannel</dt>
<dt>AlphaChannel</dt>
<dd>Same as OpacityChannel</dd>
<dt>DefaultChannels</dt>
<dd>Same as AllChannels, excluding OpacityChannel</dd>
<dt>HueChannel</dt>
<dt>LuminosityChannel</dt>
<dt>SaturationChannel</dt>
</dl>
<h3 class="const" id="ClassType">ClassType</h3>
<p>Specify the image storage class. See <a href=
"imageattrs.html#class_type">class_type</a>.</p>
<dl>
<dt>UndefinedClass</dt>
<dd>No storage class has been specified.</dd>
<dt>DirectClass</dt>
<dd class="imquote">Image is composed of pixels which represent
literal color values.</dd>
<dt>PseudoClass</dt>
<dd class="imquote">Image is composed of pixels which specify
an index in a color palette.</dd>
</dl>
<h3 class="const" id="ColorspaceType">ColorspaceType</h3>
<p class="imquote">Specify the colorspace that quantization
(color reduction and mapping) is done under or to specify the
colorspace when encoding an output image. Colorspaces are ways of
describing colors to fit the requirements of a particular
application (e.g. Television, offset printing, color
monitors). Color reduction, by default, takes place in the
RGBColorspace. Empirical evidence suggests that distances in
color spaces such as YUVColorspace or YIQColorspace correspond to
perceptual color differences more closely than do distances in
RGB space. These color spaces may give better results when color
reducing an image.</p>
<p><span class="imquote">When encoding an output image, the
colorspaces RGBColorspace, CMYKColorspace, and GRAYColorspace may
be specified. The CMYKColorspace option is only applicable when
writing TIFF, JPEG, and Adobe Photoshop bitmap (PSD)
files.</span> See <a href=
"imageattrs.html#colorspace">colorspace</a>.</p>
<p>Each version of ImageMagick defines a subset of the
colorspaces listed below. To list the subset supported by your
version, issue the command:</p>
<pre class="example">
ruby -rRMagick -e"Magick::ColorspaceType.values {|cs| puts cs}"
</pre>
<dl>
<dt>UndefinedColorspace</dt>
<dd>No colorspace has been specified.</dd>
<dt>CMYColorspace</dt>
<dt>CMYKColorspace</dt>
<dd class="imquote">Cyan-Magenta-Yellow-Black colorspace. CYMK
is a subtractive color system used by printers and
photographers for the rendering of colors with ink or emulsion,
normally on a white surface.</dd>
<dt>GRAYColorspace</dt>
<dd>Full-range grayscale</dd>
<dt>HSBColorspace</dt>
<dt>HSLColorspace</dt>
<dd>Hue, saturation, luminosity</dd>
<dt>HWBColorspace</dt>
<dd>Hue, whiteness, blackness</dd>
<dt>LABColorspace</dt>
<dt>LogColorspace</dt>
<dt>OHTAColorspace</dt>
<dt>RGBColorspace</dt>
<dd class="imquote">Red-Green-Blue colorspace</dd>
<dt>SRGBColorspace</dt>
<dd>Kodak PhotoCD sRGB. In ImageMagick, this constant is named
sRGBColorspace, but since Ruby constants must start with an
uppercase letter, I had to change it.</dd>
<dt>TransparentColorspace</dt>
<dd class="imquote">The Transparent color space behaves
uniquely in that it preserves the matte channel of the image if
it exists.</dd>
<dt>XYZColorspace</dt>
<dd>CIE XYZ</dd>
<dt>YCbCrColorspace</dt>
<dt>YCCColorspace</dt>
<dd>Kodak PhotoCD PhotoYCC</dd>
<dt>YIQColorspace</dt>
<dt>YPbPrColorspace</dt>
<dt>YUVColorspace</dt>
<dd class="imquote">Y-signal, U-signal, and V-signal
colorspace. YUV is most widely used to encode color for use in
television transmission.</dd>
</dl>
<p>The colorspaces in this group are typically associated with
the DPX and Cineon image formats used in the motion picture
industry.</p>
<dl>
<dt>Rec601LumaColorspace</dt>
<dd>Luma (Y) according to ITU-R 601</dd>
<dt>Rec601YCbCrColorspace</dt>
<dd>YCbCr according to ITU-R 601</dd>
<dt>Rec709LumaColorspace</dt>
<dd>Luma (Y) according to ITU-R 709</dd>
<dt>Rec709YCbCrColorspace</dt>
<dd>YCbCr according to ITU-R 709</dd>
</dl>
<h3 class="const" id="ComplianceType">ComplianceType</h3>
<p>Specify the color standard from which color names are chosen.
See <a href="struct.html#Pixel">to_color</a>.</p>
<dl>
<dt>SVGCompliance</dt>
<dd>Adhere to SVG color standard.</dd>
<dt>X11Compliance</dt>
<dd>Adhere to X11 color standard.</dd>
<dt>XPMCompliance</dt>
<dd>Adhere to XPM color standard.</dd>
<dt>AllCompliance</dt>
<dd>The union of the 3 color standards.</dd>
</dl>
<h3 class="const" id="CompositeOperator">CompositeOperator</h3>
<p><span class="imquote">Select the image composition algorithm
used to compose a <code>composite image</code> with a
<code>image</code>. By default, each of the <code>composite
image</code> pixels are replaced by the corresponding
<code>image</code> tile pixel. Specify
<code>CompositeOperator</code> to select a different
algorithm.</span> See <a href=
"image1.html#composite">composite</a>.</p>
<dl>
<dt>UndefinedCompositeOp</dt>
<dd>No composite operator has been specified.</dd>
<dt>AddCompositeOp</dt>
<dd class="imquote">The result of <code>composite image</code>
+ <code>image</code>, with overflow wrapping around (mod
256).</dd>
<dt>AtopCompositeOp</dt>
<dd class="imquote">The result is the same shape as
<code>image</code>, with <code>composite image</code> obscuring
<code>image</code> where the image shapes overlap. Note that
this differs from OverCompositeOp because the portion of
<code>composite image</code> outside of <code>image</code>'s
shape does not appear in the result.</dd>
<dt>BlurCompositeOp</dt>
<dd>?</dd>
<dt>BumpmapCompositeOp</dt>
<dd class="imquote">The result <code>image</code> shaded by
<code>composite image</code>.</dd>
<dt>ChangeMaskCompositeOp</dt>
<dd class="imquote">Replace any destination pixel that is the
similar to the source image's pixel (as defined by the current
fuzz factor), with transparency.</dd>
<dt>ClearCompositeOp</dt>
<dd>Make the target image transparent. The composite image is
ignored.</dd>
<dt>ColorBurnCompositeOp</dt>
<dd class="imquote">Darkens the destination color to reflect
the source color. Painting with white produces no change.</dd>
<dt>ColorDodgeCompositeOp</dt>
<dd class="imquote">Brightens the destination color to reflect
the source color. Painting with black produces no change.</dd>
<dt>ColorizeCompositeOp</dt>
<dd class="imquote">Each pixel in the result image is the
combination of the brightness of the target image and the
saturation and hue of the composite image. This is the
<em>opposite</em> of LuminizeCompositeOp.</dd>
<dt>CopyCompositeOp</dt>
<dd>Replace the target image with the composite image.</dd>
<dt>CopyBlackCompositeOp</dt>
<dd>Copy the black channel from the composite image to the
target image.</dd>
<dt>CopyBlueCompositeOp</dt>
<dd>Copy the blue channel from the composite image to the
target image.</dd>
<dt>CopyCyanCompositeOp</dt>
<dd>Copy the cyan channel from the composite image to the
target image.</dd>
<dt>CopyGreenCompositeOp</dt>
<dd>Copy the green channel from the composite image to the
target image.</dd>
<dt>CopyMagentaCompositeOp</dt>
<dd>Copy the magenta channel from the composite image to the
target image.</dd>
<dt>CopyOpacityCompositeOp</dt>
<dd>If the composite image's <a href=
"imageattrs.html#matte">matte</a> attribute is
<code>true</code>, copy the opacity channel from the composite
image to the target image. Otherwise, set the target image
pixel's opacity to the intensity of the corresponding pixel in
the composite image.</dd>
<dt>CopyRedCompositeOp</dt>
<dd>Copy the red channel from the composite image to the target
image.</dd>
<dt>CopyYellowCompositeOp</dt>
<dd>Copy the yellow channel from the composite image to the
target image.</dd>
<dt>DarkenCompositeOp</dt>
<dd>Replace target image pixels with darker pixels from the
composite image.</dd>
<dt>DifferenceCompositeOp</dt>
<dd class="imquote">The result of abs(<code>composite
image</code> - <code>image</code>). This is useful for
comparing two very similar images.</dd>
<dt>DisplaceCompositeOp</dt>
<dd>Displace target image pixels as defined by a displacement
map. The operator used by the <a href=
"image1.html#displace">displace</a> method.</dd>
<dt>DissolveCompositeOp</dt>
<dd>The operator used in the <a href=
"image1.html#dissolve">dissolve</a> method.</dd>
<dt>DistortCompositeOp</dt>
<dd>?</dd>
<dt>DivideCompositeOp</dt>
<dd>?</dd>
<dt>DstCompositeOp</dt>
<dd class="imquote">The destination is left untouched.</dd>
<dt>DstAtopCompositeOp</dt>
<dd class="imquote">The part of the destination lying inside of
the source is composited over the source and replaces the
destination.</dd>
<dt>DstInCompositeOp</dt>
<dd class="imquote">The part of the destination lying inside of
the source replaces the destination.</dd>
<dt>DstOutCompositeOp</dt>
<dd class="imquote">The part of the destination lying outside
of the source replaces the destination.</dd>
<dt>DstOverCompositeOp</dt>
<dd class="imquote">The destination is composited over the
source and the result replaces the destination.</dd>
<dt>ExclusionCompositeOp</dt>
<dd class="imquote">Produces an effect similar to that of
'difference', but appears as lower contrast. Painting with
white inverts the destination color. Painting with black
produces no change.</dd>
<dt>HardLightCompositeOp</dt>
<dd class="imquote">Multiplies or screens the colors, dependent
on the source color value. If the source color is lighter than
0.5, the destination is lightened as if it were screened. If
the source color is darker than 0.5, the destination is
darkened, as if it were multiplied. The degree of lightening or
darkening is proportional to the difference between the source
color and 0.5. If it is equal to 0.5 the destination is
unchanged. Painting with pure black or white produces black or
white.</dd>
<dt>HueCompositeOp</dt>
<dd class="imquote">Each pixel in the result image is the
combination of the hue of the target image and the saturation
and brightness of the composite image.</dd>
<dt>InCompositeOp</dt>
<dd class="imquote">The result is simply <code>composite
image</code> cut by the shape of <code>image</code>. None of
the image data of <code>image</code> is included in the
result.</dd>
<dt>LightenCompositeOp</dt>
<dd>Replace target image pixels with lighter pixels from the
composite image.</dd>
<dt>LinearBurnCompositeOp</dt>
<dd>Same as <code>LinearDodgeCompositeOp</code>, but also
subtract one from the result. Sort of a additive 'Screen' of
the images.</dd>
<dt>LinearDodgeCompositeOp</dt>
<dd class="imquote">This is equivelent to
<code>PlusCompositeOp</code> in that the color channels are
simply added, however it does not "plus" the alpha channel, but
uses the normal <code>OverCompositeOp</code> alpha blending,
which transparencies are involved. Produces a sort of additive
multiply-like result.</dd>
<dt>LinearLightCompositeOp</dt>
<dd class="imquote">Increase contrast slightly with an impact
on the foreground's tonal values.</dd>
<dt>LuminizeCompositeOp</dt>
<dd class="imquote">Each pixel in the result image is the
combination of the brightness of the composite image and the
saturation and hue of the target image. This is the
<em>opposite</em> of ColorizeCompositeOp.</dd>
<dt>MinusCompositeOp</dt>
<dd class="imquote">The result of composite image - image, with
overflow cropped to zero. The matte chanel is ignored (set to
255, full coverage).</dd>
<dt>ModulateCompositeOp</dt>
<dd>Used by the <a href="image3.html#watermark">watermark</a>
method.</dd>
<dt>MultiplyCompositeOp</dt>
<dd class="imquote">Multiplies the color of each target image
pixel by the color of the corresponding composite image pixel.
The result color is always darker.</dd>
<dt>NoCompositeOp</dt>
<dd>No composite operator has been specified.</dd>
<dt>OutCompositeOp</dt>
<dd class="imquote">The resulting image is <code>composite
image</code> with the shape of <code>image</code> cut out.</dd>
<dt>OverCompositeOp</dt>
<dd><span class="imquote">The result is the union of the the
two image shapes with <code>composite image</code> obscuring
<code>image</code> in the region of overlap.</span> The matte
channel of the composite image is respected, so that if the
composite pixel is part or all transparent, the corresponding
image pixel will show through.</dd>
<dt>OverlayCompositeOp</dt>
<dd class="imquote">Multiplies or screens the colors, dependent
on the destination color. Source colors overlay the destination
whilst preserving its highlights and shadows. The destination
color is not replaced, but is mixed with the source color to
reflect the lightness or darkness of the destination.</dd>
<dt>PegtopLightCompositeOp</dt>
<dd class="imquote">Almost equivalent to
<code>SoftLightCompositeOp</code>, but using a continuious
mathematical formula rather than two conditionally selected
formulae.</dd>
<dt>PinLightCompositeOp</dt>
<dd class="imquote">Similar to
<code>HardLightCompositeOp</code>, but using sharp linear
shadings, to similate the effects of a strong 'pinhole' light
source.</dd>
<dt>PlusCompositeOp</dt>
<dd class="imquote">The result is just the sum of the image
data. Output values are cropped to 255 (no overflow). This
operation is independent of the matte channels.</dd>
<dt>ReplaceCompositeOp</dt>
<dd class="imquote">The resulting image is image replaced with
composite image. Here the matte information is ignored.</dd>
<dt>SaturateCompositeOp</dt>
<dd>Each pixel in the result image is the combination of the
saturation of the target image and the hue and brightness of
the composite image.</dd>
<dt>ScreenCompositeOp</dt>
<dd>Multiplies the inverse of each image's color
information.</dd>
<dt>SoftLightCompositeOp</dt>
<dd class="imquote">Darkens or lightens the colors, dependent
on the source color value. If the source color is lighter than
0.5, the destination is lightened. If the source color is
darker than 0.5, the destination is darkened, as if it were
burned in. The degree of darkening or lightening is
proportional to the difference between the source color and
0.5. If it is equal to 0.5, the destination is unchanged.
Painting with pure black or white produces a distinctly darker
or lighter area, but does not result in pure black or
white.</dd>
<dt>SrcAtopCompositeOp</dt>
<dd class="imquote">The part of the source lying inside of the
destination is composited onto the destination.</dd>
<dt>SrcCompositeOp</dt>
<dd class="imquote">The source is copied to the destination.
The destination is not used as input.</dd>
<dt>SrcInCompositeOp</dt>
<dd class="imquote">he part of the source lying inside of the
destination replaces the destination.</dd>
<dt>SrcOutCompositeOp</dt>
<dd class="imquote">The part of the source lying outside of the
destination replaces the destination.</dd>
<dt>SrcOverCompositeOp</dt>
<dd class="imquote">The source is composited over the
destination.</dd>
<dt>SubtractCompositeOp</dt>
<dd class="imquote">The result of <code>composite image</code>
- <code>image</code>, with underflow wrapping around (mod 256).
The add and subtract operators can be used to perform
reversable transformations.</dd>
<dt>ThresholdCompositeOp</dt>
<dd>?</dd>
<dt>VividLightCompositeOp</dt>
<dd class="imquote">A modified
<code>LinearLightCompositeOp</code> designed to preserve very
stong primary and secondary colors in the image.</dd>
<dt>XorCompositeOp</dt>
<dd class="imquote">The result is the image data from both
<code>composite image</code> and <code>image</code> that is
outside the overlap region. The overlap region will be
blank.</dd>
</dl>
<h3 class="const" id="CompressionType">CompressionType</h3>
<p><span class="imquote">Express the desired compression type
when encoding an image. Be aware that most image types only
support a sub-set of the available compression types. If the
compression type specified is incompatible with the image,
ImageMagick selects a compression type compatible with the image
type.</span> See <a href=
"imageattrs.html#compression">compression</a>.</p>
<dl>
<dt>UndefinedCompression</dt>
<dd>No compression type has been specified.</dd>
<dt>NoCompression</dt>
<dd>The default for most formats.</dd>
<dt>B44Compression</dt>
<dd>Available in ImageMagick 6.5.5-4 and later.</dd>
<dt>B44ACompression</dt>
<dd>Available in ImageMagick 6.5.5-4 and later.</dd>
<dt>BZipCompression</dt>
<dd class="imquote">BZip (Burrows-Wheeler block-sorting text
compression algorithm and Huffman coding) as used by bzip2
utilities</dd>
<dt>DXT1Compression</dt>
<dd>Available in ImageMagick 6.3.9-3 and later.</dd>
<dt>DXT3Compression</dt>
<dd>Available in ImageMagick 6.3.9-3 and later.</dd>
<dt>DXT5Compression</dt>
<dd>Available in ImageMagick 6.3.9-3 and later.</dd>
<dt>FaxCompression</dt>
<dd class="imquote">CCITT Group 3 FAX compression</dd>
<dt>Group4Compression</dt>
<dd class="imquote">CCITT Group 4 FAX compression (used only
for TIFF)</dd>
<dt>JPEGCompression</dt>
<dd>JPEG compression. See <a href=
"http://www.faqs.org/faqs/jpeg-faq/part1/">The JPEG image
compression FAQ</a>.</dd>
<dt>JPEG2000Compression</dt>
<dd>JPEG2000 compression for compressed PDF images.</dd>
<dt>LosslessJPEGCompression</dt>
<dd>This compression format is almost never used.</dd>
<dt>LZWCompression</dt>
<dd class="imquote">Lempel-Ziv-Welch (LZW) compression</dd>
<dt>PizCompression</dt>
<dd>Available in ImageMagick 6.5.5-4 and later.</dd>
<dt>Pxr24Compression</dt>
<dd>Available in ImageMagick 6.5.5-4 and later.</dd>
<dt>RLECompression</dt>
<dd>See the Wikipedia page for <a href=
"http://en.wikipedia.org/wiki/Run_length_encoding">Run-length
encoding</a>.</dd>
<dt>ZipCompression</dt>
<dd class="imquote">Lempel-Ziv compression (LZ77) as used in
PKZIP and GNU gzip.</dd>
<dt>ZipSCompression</dt>
<dd>Available in ImageMagick 6.5.5-4 and later.</dd>
</dl>
<h3 class="const" id="DecorationType">DecorationType</h3>
<p>Use with the <a href="draw.html#decorate">decorate=</a> method
in the Draw class to specify the text decoration for the <a href=
"draw.html#annotate">annotate</a> method.</p>
<dl>
<dt>NoDecoration</dt>
<dd>Don't decorate the text.</dd>
<dt>UnderlineDecoration</dt>
<dd>Underline the text.</dd>
<dt>OverlineDecoration</dt>
<dd>Overline the text.</dd>
<dt>LineThroughDecoration</dt>
<dd>Draw a horizontal line through the middle of the text.</dd>
</dl>
<h3 class="const" id="DisposeType">DisposeType</h3>
<p>The value of the <a href="imageattrs.html#dispose">dispose</a>
attribute.</p>
<dl>
<dt>UndefinedDispose</dt>
<dd>No disposal specified.</dd>
<dt>NoneDispose</dt>
<dd>Do not dispose between frames.</dd>
<dt>BackgroundDispose</dt>
<dd>Overwrite the image area with the background color.</dd>
<dt>PreviousDispose</dt>
<dd>Overwrite the image area with what was there prior to