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imageattrs.html
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imageattrs.html
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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 1st December 2004), see www.w3.org" />
<title>RMagick 0.0.0: class Image (attribute methods)</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. */
/*]]>*/
</style>
</head>
<body>
<h6 id="header">RMagick 0.0.0 User's Guide and Reference</h6>
<div class="nav">
« <a href="ilist.html">Prev</a> | <a href=
"index.html">Contents</a> | <a href=
"image1.html">Next</a> »
</div>
<h1>class Image <span class="superclass">< Object</span>
(attribute methods)<br />
<span class="mixin">mixes in Comparable</span></h1>
<div id="toc">
<h2>Table of Contents</h2>
<h3>attribute methods</h3>
<div>
<div class="toccol">
<ul>
<li><a href="#background_color">background_color</a></li>
<li><a href="#base_columns">base_columns</a></li>
<li><a href="#base_filename">base_filename</a></li>
<li><a href="#base_rows">base_rows</a></li>
<li><a href="#bias">bias</a></li>
<li><a href=
"#black_point_compensation">black_point_compensation</a></li>
<li><a href="#blur">blur</a></li>
<li><a href="#border_color">border_color</a></li>
<li><a href="#bounding_box">bounding_box</a></li>
<li><a href="#chromaticity">chromaticity</a></li>
<li><a href="#class_type">class_type</a></li>
<li><a href="#color_profile">color_profile</a></li>
<li><a href="#colors">colors</a></li>
<li><a href="#colorspace">colorspace</a></li>
<li><a href="#columns">columns</a></li>
<li><a href="#compose">compose</a></li>
<li><a href="#compression">compression</a></li>
<li><a href="#delay">delay</a></li>
<li><a href="#density">density</a></li>
<li><a href="#depth">depth</a></li>
</ul>
</div>
<div class="toccol">
<ul>
<li><a href="#directory">directory</a></li>
<li><a href="#dispose">dispose</a></li>
<li><a href="#endian">endian</a></li>
<li><a href="#extract_info">extract_info</a></li>
<li><a href="#filename">filename</a></li>
<li><a href="#filesize">filesize</a></li>
<li><a href="#filter">filter</a></li>
<li><a href="#format">format</a></li>
<li><a href="#fuzz">fuzz</a></li>
<li><a href="#gamma">gamma</a></li>
<li><a href="#geometry">geometry</a></li>
<li><a href="#image_type">image_type</a></li>
<li><a href="#interlace">interlace</a></li>
<li><a href="#iptc_profile">iptc_profile</a></li>
<li><a href="#mask">mask</a></li>
<li><a href="#matte">matte</a></li>
<li><a href=
"#mean_error_per_pixel">mean_error_per_pixel</a></li>
<li><a href="#mime_type">mime_type</a></li>
<li><a href="#monitor">monitor</a></li>
<li><a href="#montage">montage</a></li>
</ul>
</div>
<div class="toccol">
<ul>
<li><a href=
"#normalized_mean_error">normalized_mean_error</a></li>
<li><a href=
"#normalized_maximum_error">normalized_maximum_error</a></li>
<li><a href="#number_colors">number_colors</a></li>
<li><a href="#offset">offset</a></li>
<li><a href="#opacity">opacity</a></li>
<li><a href="#orientation">orientation</a></li>
<li><a href="#page">page</a></li>
<li><a href=
"#pixel_interpolation_method">pixel_interpolation_method</a></li>
<li><a href="#quality">quality</a></li>
<li><a href="#quantum_depth">quantum_depth</a></li>
<li><a href="#rendering_intent">rendering_intent</a></li>
<li><a href="#rows">rows</a></li>
<li><a href="#scene">scene</a></li>
<li><a href="#start_loop">start_loop</a></li>
<li><a href="#ticks_per_second">ticks_per_second</a></li>
<li><a href="#total_colors">total_colors</a></li>
<li><a href="#units">units</a></li>
<li><a href=
"#virtual_pixel_method">virtual_pixel_method</a></li>
<li><a href="#x_resolution">x_resolution</a></li>
<li><a href="#y_resolution">y_resolution</a></li>
</ul>
</div>
</div>
</div>
<h2 class="methods">attribute methods</h2>
<div class="sig">
<h3 id="background_color">background_color</h3>
<p><span class="arg">image.</span>background_color ->
<em>aString</em><br />
<span class="arg">image</span>.background_color = <span class=
"arg">aString</span> or <span class="arg">aPixel</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image's background color. By default the background
color is "white".</p>
<h4>Arguments</h4>Either a <a href=
"imusage.html#color_names">color name</a> or a <a href=
"struct.html#Pixel">Pixel</a> object.
<h4>Returns</h4>
<p>A color name.</p>
</div>
<div class="sig">
<h3 id="base_columns">base_columns</h3>
<p><span class="arg">image.</span>base_columns ->
<em>anInteger</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The number of columns in the image before any
transformations. Get-only.</p>
</div>
<div class="sig">
<h3 id="base_filename">base_filename</h3>
<p><span class="arg">image</span>.base_filename ->
<em>aString</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image's original filename before any transformations.
Get-only.</p>
</div>
<div class="sig">
<h3 id="base_rows">base_rows</h3>
<p><span class="arg">image.</span>base_rows ->
<em>anInteger</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The number of rows in the image before any transformations.
Get-only.</p>
</div>
<div class="sig">
<h3 id="bias">bias</h3>
<p><span class="arg">image</span>.bias -> bias<br />
<span class="arg">image</span>.bias = <span class=
"arg">aFloat</span><br />
<span class="arg">image</span>.bias = <span class=
"arg">aString</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p class="imquote">Add bias when convolving an image</p>
<h4>Argument</h4>
<p>Either a number between 0.0 and 1.0 or a string in the form
"NN%".</p>
</div>
<div class="sig">
<h3 id="black_point_compensation">black_point_compensation</h3>
<p><span class="arg">image</span>.black_point_compensation
-> <code>true</code> or <code>false</code><br />
<span class="arg">image</span>.black_point_compensation =
<code>true</code> or <code>false</code> -> <em>self</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>Use black point compensation. Typically used in CMYK-to-RGB
conversion along with <code>image.</code><a href=
"#rendering_intent">rendering_intent</a>=<a href=
"constants.html#RenderingIntent">Magick::RelativeIntent</a></p>
</div>
<div class="sig">
<h3 id="blur">blur</h3>
<p><span class="arg">image.</span>blur ->
<em>aFloat</em><br />
<span class="arg">image.</span>blur = <span class=
"arg">aFloat</span></p>
</div>
<div class="desc">
<h4>Description</h4>The blur factor to use when resizing. See
<a href="image3.html#resize">resize</a>.
<h4>Argument</h4>
<p>> 1.0 is blurry, < 1.0 is sharp.</p>
</div>
<div class="sig">
<h3 id="border_color">border_color</h3>
<p><span class="arg">image.</span>border_color ->
<em>aString</em><br />
<span class="arg">image.</span>border_color = <span class=
"arg">aString</span> or <span class="arg">aPixel</span></p>
</div>
<div class="desc">
<h4>Description</h4>The image's border color. The default
border color is "#dfdfdf" (gray).
<h4>Arguments</h4>
<p>Either a <a href="imusage.html#color_names">color name</a>
or a <a href="struct.html#Pixel">Pixel</a> object.</p>
<h4>Returns</h4>
<p>A color name.</p>
</div>
<div class="sig">
<h3 id="bounding_box">bounding_box</h3>
<p><span class="arg">bounding_box</span> ->
<em>aRectangle</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image's <em>bounding box</em>. The bounding box is the
rectangle that encloses all the pixels not in the border color.
Uses the current <a href="#fuzz">fuzz</a> value. Get-only.</p>
<h4>Returns</h4>A <a href="struct.html#Rectangle">Rectangle</a>
object.
<h4>Example</h4>
<p>In this example, the bounding box is the gray square
enclosing the blue circle. (The coordinates and red circles
were added after the bounding box was computed.)</p>
<p><a href="javascript:popup('bounding_box.rb.html')"><img src=
"ex/bounding_box.gif" alt="ex/bounding_box.rb" title=
"Click to see the example script" /></a></p>
</div>
<div class="sig">
<h3 id="chromaticity">chromaticity</h3>
<p><span class="arg">image.</span>chromaticity ->
<em>aChromaticity</em><br />
<span class="arg">image.</span>chromaticity = <span class=
"arg">aChromaticity</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The <span class="imquote">red, green, blue, and white-point
chromaticity values.</span>.</p>
<h4>Arguments</h4>A <a href=
"struct.html#Chromaticity">Chromaticity</a> object.
<h4>Returns</h4>A <a href=
"struct.html#Chromaticity">Chromaticity</a> object.
</div>
<div class="sig">
<h3 id="class_type">class_type</h3>
<p><span class="arg">image.</span>class_type ->
<em>aClassType</em><br />
<span class="arg">image.</span>class_type = <span class=
"arg">aClassType</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image's <em>storage class</em>. <span class="imquote">If
DirectClass then the pixels contain valid RGB or CMYK colors.
If PseudoClass then the image has a colormap referenced by the
pixel's index member.</span></p>
<h4>Arguments</h4>
<p>A <a href="constants.html#ClassType">ClassType</a>
constant.</p>
<h4>Returns</h4>
<p>A <a href="constants.html#ClassType">ClassType</a>
constant.</p>
</div>
<div class="sig">
<h3 id="color_profile">color_profile</h3>
<p><span class="arg">image.</span>color_profile ->
<em>aString</em><br />
<span class="arg">image.</span>color_profile = <span class=
"arg">aString</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The <a href="http://www.color.org/icc_specs2.html">ICC color
profile</a>.</p>
<h4>Arguments</h4>
<p>A color profile is represented as a string. If the argument
is <code>nil</code> instead of <span class="arg">aString</span>
then any ICC color profile present in the image is deleted.</p>
<p>The setter form of this attribute deletes any existing ICC
color profile(s) before adding the new one. If you need to add
both source and destination profiles use <a href=
"image1.html#add_profile">add_profile</a> or <a href=
"image3.html#profile_bang">profile!</a>.</p>
<h4>Returns</h4>
<p>The current color profile, or <code>nil</code> if there is
no profile.</p>
<h4>See also</h4>
<p><a href="image1.html#add_profile">add_profile</a>, <a href=
"image1.html#delete_profile">delete_profile</a>, <a href=
"image1.html#each_profile">each_profile</a>, <a href=
"image3.html#profile_bang">profile!</a></p>
</div>
<div class="sig">
<h3 id="colors">colors</h3>
<p><span class="arg">image.</span>colors ->
<em>anInteger</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The number of colors in the colormap. Only meaningful for
<a href="constants.html#ClassType">PseudoClass</a> images.
Get-only.</p>
</div>
<div class="sig">
<h3 id="colorspace">colorspace</h3>
<p><span class="arg">image.</span>colorspace ->
<em>aColorspace</em><br />
<span class="arg">image.</span>colorspace = <span class=
"arg">aColorspace</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p class="imquote">Image pixel interpretation. If the <a href=
"constants.html#ColorspaceType">colorspace</a> is RGBColorspace
the pixels are red, green, blue. If <a href="#matte">matte</a>
is true, then red, green, blue, and opacity. If it is
CMYKColorspace, the pixels are cyan, yellow, magenta, black.
Otherwise the colorspace is ignored.</p>
<h4>Arguments</h4>
<p>A <a href="constants.html#Colorspace">Colorspace</a>
constant.</p>
<h4>Returns</h4>
<p>A <a href="constants.html#Colorspace">Colorspace</a>
constant.</p>
</div>
<div class="sig">
<h3 id="columns">columns</h3>
<p><span class="arg">image.</span>columns ->
<em>anInteger</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The width of the image in pixels. Get-only.</p>
</div>
<div class="sig">
<h3 id="compose">compose</h3>
<p><span class="arg">image.</span>compose ->
<em>aCompositeOperator</em><br />
<span class="arg">image.</span>compose = <span class=
"arg">aCompositeOperator</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image composite operator. The default is
OverCompositeOp. See <a href=
"ilist.html#montage">montage</a>.</p>
<h4>Arguments</h4>
<p>A <a href="constants.html#CompositeOperator">composite
operator</a> constant.</p>
<h4>Returns</h4>
<p>A <a href="constants.html#CompositeOperator">composite
operator</a> constant.</p>
</div>
<div class="sig">
<h3 id="compression">compression</h3>
<p><span class="arg">image.</span>compression ->
<em>aCompressionType</em><br />
<span class="arg">image.</span>compression = <span class=
"arg">aCompressionType</span></p>
</div>
<div class="desc">
<h4>Description</h4>The image compression type. The default is
the compression type of the specified image file.
<h4>Arguments</h4>
<p>A <a href=
"constants.html#CompressionType">CompressionType</a>
constant.</p>
<h4>Returns</h4>
<p>A <a href=
"constants.html#CompressionType">CompressionType</a>
constant.</p>
</div>
<div class="sig">
<h3 id="delay">delay</h3>
<p><span class="arg">image.</span>delay ->
<em>anInteger</em><br />
<span class="arg">image.</span>delay = <span class=
"arg">anInteger</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>Number of ticks which must expire before displaying the next
image in an animated sequence. The default number of ticks is
0. By default there are 100 ticks per second but this number
can be changed via the <a href=
"#ticks_per_second">ticks_per_second</a> attribute.</p>
<h4>Arguments</h4>An integer value between 0 and 65535,
inclusive.
<h4>Returns</h4>
<p>The current delay value.</p>
</div>
<div class="sig">
<h3 id="density">density</h3>
<p><span class="arg">image.</span>density ->
<em>aString</em><br />
<span class="arg">image.</span>density = <span class=
"arg">aString</span> or <span class="arg">aGeometry</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The <span class="imquote">vertical and horizontal resolution
in pixels of the image.</span> The default is "72x72".</p>
<h4>Arguments</h4>
<p>The density may be expressed either as a string or a
<a href="struct.html#Geometry">Geometry</a> object. If a
string, it is in the form "XxY", or simply "X". If "Y" is
omitted it is set to "X". To specify the density with a
Geometry object, set the <code>width</code> attribute to the x
resolution and the <code>height</code> argument to the y
resolution. If <code>height</code> is nil, <code>width</code>
will be used as the y resolution as well.</p>
<h4>Returns</h4>
<p>The image density represented as a string.</p>
<h4>See also</h4>
<p>Also see <a href="#Image.x_resolution">x_resolution</a> and
<a href="#Image.y_resolution">y_resolution</a>.</p>
</div>
<div class="sig">
<h3 id="depth">depth</h3>
<p><span class="arg">image.</span>depth ->
<em>anInteger</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image depth (8, 16, or 32). Get-only.</p>
</div>
<div class="sig">
<h3 id="directory">directory</h3>
<p><span class="arg">image.</span>directory ->
<em>aString</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p><span class="imquote">Tile names from within an image
montage. Only valid after calling <a href=
"ilist.html#montage">montage</a> or reading a MIFF file which
contains a directory.</span> Get-only.</p>
<h4>Returns</h4>
<p>A newline ("\n")-delimited list of the images in the
montage.</p>
</div>
<div class="sig">
<h3 id="dispose">dispose</h3>
<p><span class="arg">image.</span>dispose ->
<em>anInteger</em><br />
<span class="arg">image.</span>dispose = <span class=
"arg">aDisposeType</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p class="imquote">GIF disposal method. This attribute is used
to control how successive images are rendered (how the
preceding image is disposed of) when creating a GIF
animation.</p>
<h4>Arguments</h4>
<p>An integer corresponding to the disposal method.</p>
<h4>Returns</h4>A <a href=
"constants.html#DisposeType">DisposeType</a> constant.
</div>
<div class="sig">
<h3 id="endian">endian</h3>
<p><span class="arg">image.</span>endian ->
<em>anEndianType</em><br />
<span class="arg">image.</span>endian = <span class=
"arg">anEndianType</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>Get or set the endian attribute. <em>(As best I can tell,
only the TIFF format supports this attribute.)</em></p>
<h4>Arguments</h4>
<p>An <a href="constants.html#EndianType">EndianType</a>
value.</p>
<h4>Returns</h4>
<p>An <a href="constants.html#EndianType">EndianType</a>
value.</p>
</div>
<div class="sig">
<h3 id="extract_info">extract_info</h3>
<p><span class="arg">image.</span>extract_info ->
<em>aRectangle</em><br />
<span class="arg">image.</span>extract_info = <span class=
"arg">aRectangle</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>Specify a rectangle within an image, or retrieve the
rectangle specified when the image was constituted. See
<a href="info.html#extract">extract=</a>.</p>
<h4>Arguments</h4>
<p>A <a href="struct.html#Rectangle">Rectangle</a> object.</p>
<h4>Returns</h4>
<p>A <a href="struct.html#Rectangle">Rectangle</a> object.</p>
</div>
<div class="sig">
<h3 id="filename">filename</h3>
<p><span class="arg">image.</span>filename ->
<em>aString</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image filename. Get-only.</p>
</div>
<div class="sig">
<h3 id="filesize">filesize</h3>
<p><span class="arg">image.</span>filesize ->
<em>anInteger</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image filesize in bytes. Get-only.</p>
</div>
<div class="sig">
<h3 id="filter">filter</h3>
<p><span class="arg">image.</span>filter ->
<em>aFilterType</em><br />
<span class="arg">image.</span>filter = <span class=
"arg">aFilterType</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p class="imquote">Filter to use when resizing image. The
reduction filter employed has a significant effect on the time
required to resize an image and the resulting quality. The
default filter is Lanczos which has been shown to produce high
quality results when reducing most images.</p>
<h4>Arguments</h4>
<p>A <a href="constants.html#FilterType">FilterType</a>
constant.</p>
<h4>Returns</h4>A <a href=
"constants.html#FilterType">FilterType</a> constant.
</div>
<div class="sig">
<h3 id="format">format</h3>
<p><span class="arg">image.</span>format ->
<em>aString</em><br />
<span class="arg">image.</span>format = <span class=
"arg">aString</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image encoding format. For example, "GIF" or "PNG". See
<a href="magick.html#formats">formats</a>.</p>
<h4>Arguments</h4>
<p>The format name.</p>
<h4>Returns</h4>
<p>The format name.</p>
</div>
<div class="sig">
<h3 id="fuzz">fuzz</h3>
<p><span class="arg">image.</span>fuzz ->
<em>aFloat</em><br />
<span class="arg">image.</span>fuzz = <span class=
"arg">aNumeric</span> or <span class="arg">aString</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p><span class="imquote">Colors within this distance are
considered equal. A number of algorithms search for a target
color. By default the color must be exact. Use this</span>
[attribute] <span class="imquote">to match colors that are
close to the target color in RGB space.</span></p>
<p>See <a href="image3.html#opaque">opaque</a>, <a href=
"image3.html#texture_floodfill">texture_floodfill</a>, and
<a href="image3.html#transparent">transparent</a>.</p>
<h4>Arguments</h4>
<p>The argument may be a floating-point numeric value or a
string in the form "NN%". In the second case, the argument is
computed as a percentage of <a href=
"constants.html#Miscellaneous_constants">MaxRGB</a>. For
example, a value of '5%' sets <code>fuzz</code> to
0.05*MaxRGB.</p>
<h4>Returns</h4>
<p>A <code>Float</code></p>
</div>
<div class="sig">
<h3 id="gamma">gamma</h3>
<p><span class="arg">image.</span>gamma ->
<em>aFloat</em><br />
<span>image.</span>gamma = <span class="arg">aFloat</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p class="imquote">Gamma level of the image. The same color
image displayed on two different workstations may look
different due to differences in the display monitor. Use gamma
correction to adjust for this color difference.</p>
</div>
<div class="sig">
<h3 id="geometry">geometry</h3>
<p><span class="arg">image.</span>geometry ->
<em>aString</em><br />
<span class="arg">image.</span>geometry = <span class=
"arg">aString</span> or <span class="arg">aGeometry</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p class="imquote">Preferred size of the image when
encoding.</p>
<h4>Arguments</h4>
<p>A <a href="imusage.html#geometry">geometry string</a> or a
<a href="struct.html#Geometry">Geometry</a> object.</p>
<h4>Returns</h4>
<p>A <a href="imusage.html#geometry">geometry string</a>.</p>
</div>
<div class="sig">
<h3 id="image_type">image_type</h3>
<p><span class="arg">image.</span>image_type ->
<em>anImageType</em></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The image type classification. For example, GrayscaleType.
Don't confuse this attribute with the <a href=
"#format">format</a>, that is "GIF" or "JPG".</p>
<h4>Returns</h4>
<p>An <a href="constants.html#ImageType">ImageType</a>
value.</p>
</div>
<div class="sig">
<h3 id="interlace">interlace</h3>
<p><span class="arg">image.</span>interlace ->
<em>anInterlaceType</em><br />
<span class="arg">image.</span>interlace = <span class=
"arg">anInterlaceType</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p class="imquote">The type of interlacing scheme (default
NoInterlace). This option is used to specify the type of
interlacing scheme for raw image formats such as RGB or YUV.
NoInterlace means do not interlace, LineInterlace uses scanline
interlacing, and PlaneInterlace uses plane interlacing.
PartitionInterlace is like PlaneInterlace except the different
planes are saved to individual files (e.g. image.R, image.G,
and image.B). Use LineInterlace or PlaneInterlace to create an
interlaced GIF or progressive JPEG image.</p>
<h4>Arguments</h4>
<p>An <a href="constants.html#InterlaceType">InterlaceType</a>
constant.</p>
<h4>Returns</h4>
<p>An <a href="constants.html#InterlaceType">InterlaceType</a>
constant.</p>
</div>
<div class="sig">
<h3 id="iptc_profile">iptc_profile</h3>
<p><span class="arg">image.</span>iptc_profile ->
<em>aString</em><br />
<span class="arg">image.</span>iptc_profile = <span class=
"arg">aString</span></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The <a href="http://www.iptc.org/IIM/">International Press
Telecommunications Council profile</a>.</p>
<h4>Arguments</h4>
<p>A IPTC profile is represented as a string. If the argument
is <code>nil</code> instead of <span class="arg">aString</span>
then any IPTC profile present in the image is deleted.</p>
<h4>Returns</h4>
<p>The current IPTC profile, or <code>nil</code> if there is no
profile.</p>
<h4>See also</h4>
<p><a href="image1.html#add_profile">add_profile</a>, <a href=
"image1.html#delete_profile">delete_profile</a>, <a href=
"image1.html#each_profile">each_profile</a>. <a href=
"image3.html#profile_bang">profile!</a></p>
</div>
<div class="sig">
<h3 id="mask">mask</h3>
<p><span class="arg">image</span>.mask -> <em>anImage</em>
or <code>nil</code><br />
<span class="arg">image.</span>mask = <em>anImage</em> or
<em>anImageList</em> or <code>nil</code></p>
</div>
<div class="desc">
<h4>Description</h4>
<p>The <code>mask=</code> attribute writer sets an image clip
mask created from the specified mask image. <span class=
"imquote">The mask image must have the same dimensions as the
image being masked.</span> If not, the mask image is resized to
match. <span class="imquote">If the mask image has an alpha
channel the opacity of each pixel is used to define the mask.
Otherwise, the intensity (gray level) of each pixel is
used.</span></p>
<p>In general, if the mask image does not have an alpha
channel, a white pixel in the mask prevents changes to the
corresponding pixel in the image being masked, while a black