uTools-Manuals/docs/php/imagecreatefrompng.html
2019-04-08 23:22:26 +08:00

83 lines
8.4 KiB
HTML

<!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>由文件或 URL 创建一个新图象。</title>
</head>
<body class="docs"><div id="layout">
<div id="layout-content"><div id="function.imagecreatefrompng" class="refentry">
<div class="refnamediv">
<h1 class="refname">imagecreatefrompng</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">imagecreatefrompng</span> &mdash; <span class="dc-title">由文件或 URL 创建一个新图象。</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.imagecreatefrompng-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="methodname"><strong>imagecreatefrompng</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$filename</code></span>
) : <span class="type">resource</span></div>
<p class="para rdfs-comment"> <span class="function"><strong>imagecreatefrompng()</strong></span>
返回一图像标识符,代表了从给定的文件名取得的图像。
</p>
<div class="tip"><strong class="tip">Tip</strong><p class="simpara">如已启用<a href="filesystem.configuration.html#ini.allow_url_fopen" class="link">fopen 包装器</a>,在此函数中, URL 可作为文件名。关于如何指定文件名详见 <span class="function"><a href="fopen.html" class="function">fopen()</a></span>。各种
wapper 的不同功能请参见 <a href="wrappers.html" class="xref">支持的协议和封装协议</a>,注意其用法及其可提供的预定义变量。</p></div>
</div>
<div class="refsect1 parameters" id="refsect1-function.imagecreatefrompng-parameters">
<h3 class="title">参数</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">filename</code></dt>
<dd>
<p class="para">
PNG 图像的路径。
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.imagecreatefrompng-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">成功后返回图象资源,失败后返回 <strong><code>FALSE</code></strong></p>
</div>
<div class="refsect1 examples" id="refsect1-function.imagecreatefrompng-examples">
<h3 class="title">范例</h3>
<div class="example" id="example-3683">
<p><strong>Example #1 处理创建 PNG 过程中的错误 </strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">LoadPNG</span><span style="color: #007700">(</span><span style="color: #0000BB">$imgname</span><span style="color: #007700">)<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/*&nbsp;Attempt&nbsp;to&nbsp;open&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$im&nbsp;</span><span style="color: #007700">=&nbsp;@</span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #0000BB">$imgname</span><span style="color: #007700">);<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/*&nbsp;See&nbsp;if&nbsp;it&nbsp;failed&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">if(!</span><span style="color: #0000BB">$im</span><span style="color: #007700">)<br />&nbsp;&nbsp;&nbsp;&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/*&nbsp;Create&nbsp;a&nbsp;blank&nbsp;image&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$im&nbsp;&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecreatetruecolor</span><span style="color: #007700">(</span><span style="color: #0000BB">150</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">30</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$bgc&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecolorallocate</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$tc&nbsp;&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecolorallocate</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">);<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">imagefilledrectangle</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">150</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">30</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$bgc</span><span style="color: #007700">);<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/*&nbsp;Output&nbsp;an&nbsp;error&nbsp;message&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">imagestring</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">5</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">5</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'Error&nbsp;loading&nbsp;'&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">$imgname</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$tc</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">$im</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">header</span><span style="color: #007700">(</span><span style="color: #DD0000">'Content-Type:&nbsp;image/png'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$img&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">LoadPNG</span><span style="color: #007700">(</span><span style="color: #DD0000">'bogus.image'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">imagepng</span><span style="color: #007700">(</span><span style="color: #0000BB">$img</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$img</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
<div class="example-contents"><p>以上例程的输出类似于:</p></div>
<div class="mediaobject">
<div class="imageobject">
<img src="images/21009b70229598c6a80eef8b45bf282b-imagecreatefrompng.png" alt="imagecreatefrompng() 例子" width="150" height="30" />
</div>
</div>
</div>
</div>
<div class="refsect1 notes" id="refsect1-function.imagecreatefrompng-notes">
<h3 class="title">注释</h3>
<div class="warning"><strong class="warning">Warning</strong><p class="para">Windows 版本的 PHP 在 4.3.0
版之前不支持通过此函数访问远程文件,即使已经启用 <a href="filesystem.configuration.html#ini.allow-url-fopen" class="link">allow_url_fopen</a>.
</p></div>
</div>
</div></div></div></body></html>