<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images</title>
</head>
<body><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.imagerotate.html">imagerotate</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.imagescale.html">imagescale</a></div>
<div class="up"><a href="ref.image.html">GD and Image Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="function.imagesavealpha" class="refentry">
<div class="refnamediv">
<h1 class="refname">imagesavealpha</h1>
<p class="verinfo">(PHP 4 >= 4.3.2, PHP 5)</p><p class="refpurpose"><span class="refname">imagesavealpha</span> — <span class="dc-title">Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.imagesavealpha-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">bool</span> <span class="methodname"><strong>imagesavealpha</strong></span>
( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$image</code></span>
, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$saveflag</code></span>
)</div>
<p class="para rdfs-comment">
<span class="function"><strong>imagesavealpha()</strong></span> sets the flag to attempt to save
full alpha channel information (as opposed to single-color transparency)
when saving PNG images.
</p>
<p class="para">
You have to unset alphablending
(<em>imagealphablending($im, false)</em>), to use it.
</p>
<p class="para">
Alpha channel is not supported by all browsers, if you have problem with
your browser, try to load your script with an alpha channel compliant
browser, e.g. latest Mozilla.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.imagesavealpha-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">
image</code></em></span><dd>
<p class="para">An image resource, returned by one of the image creation functions,
such as <span class="function"><a href="function.imagecreatetruecolor.html" class="function">imagecreatetruecolor()</a></span>.</p></dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">saveflag</code></em></span>
<dd>
<p class="para">
Whether to save the alpha channel or not. Default to <strong><code>FALSE</code></strong>.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.imagesavealpha-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns <strong><code>TRUE</code></strong> on success or <strong><code>FALSE</code></strong> on failure.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.imagesavealpha-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-3273">
<p><strong>Example #1 <span class="function"><strong>imagesavealpha()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Load a png image with alpha channels<br /></span><span style="color: #0000BB">$png </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #DD0000">'./alphachannel_example.png'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Do required operations<br /><br />// Turn off alpha blending and set alpha flag<br /></span><span style="color: #0000BB">imagealphablending</span><span style="color: #007700">(</span><span style="color: #0000BB">$png</span><span style="color: #007700">, </span><span style="color: #0000BB">false</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagesavealpha</span><span style="color: #007700">(</span><span style="color: #0000BB">$png</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Output image to browser<br /></span><span style="color: #0000BB">header</span><span style="color: #007700">(</span><span style="color: #DD0000">'Content-Type: image/png'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">imagepng</span><span style="color: #007700">(</span><span style="color: #0000BB">$png</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$png</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.imagesavealpha-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">This function requires GD 2.0.1 or later (2.0.28 or later is recommended).</span></p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.imagesavealpha-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.imagealphablending.html" class="function" rel="rdfs-seeAlso">imagealphablending()</a> - Set the blending mode for an image</span></li>
</ul>
</p>
</div>
</div><hr /><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.imagerotate.html">imagerotate</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.imagescale.html">imagescale</a></div>
<div class="up"><a href="ref.image.html">GD and Image Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
