怎样使用imagecreatefromxpm函数结合GD库来实现基本的图像处理操作？

<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 这部分与文章内容无关，可以是任何PHP代码</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"开始执行PHP脚本...\n"</span></span><span>;
</span><span><span class="hljs-title function_ invoke__">date_default_timezone_set</span></span><span>(</span><span><span class="hljs-string">'Asia/Shanghai'</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"当前时间："</span></span><span> . </span><span><span class="hljs-title function_ invoke__">date</span></span><span>(</span><span><span class="hljs-string">'Y-m-d H:i:s'</span></span><span>) . </span><span><span class="hljs-string">"\n"</span></span><span>;

</span><span><span class="hljs-meta">?></span></span><span>

<hr>

</span><span><span class="hljs-meta"><?php</span></span><span>
<span class="hljs-comment">/*
文章正文：怎样使用imagecreatefromxpm函数结合GD库来实现基本的图像处理操作？
*/</span>

</span><span><span class="hljs-comment">// 1. 简介</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>简介</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>在PHP中，GD库提供了丰富的图像处理功能。<strong>imagecreatefromxpm</strong>函数可以从XPM格式的图像文件创建图像资源，之后可以对图像进行基本处理，如绘制、调整颜色或保存为其他格式。</p>"</span></span><span>;

</span><span><span class="hljs-comment">// 2. 安装与环境</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>安装与环境</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>确保PHP安装了GD库，可以通过 <code>phpinfo()

// 获取图像尺寸
\$width = imagesx(\$img);
\$height = imagesy(\$img);
echo \"图像宽度: \$width, 高度: \$height\\n\";

\$newImg = imagecreatetruecolor(\$width, \$height);

imagecopy(\$newImg, \$img, 0, 0, 0, 0, \$width, \$height);

// 绘制矩形
\$red = imagecolorallocate(\$newImg, 255, 0, 0);
imagerectangle(\$newImg, 10, 10, 50, 50, \$red);

// 保存为PNG
imagepng(\$newImg, 'output.png');

// 释放资源
imagedestroy(\$img);
imagedestroy(\$newImg);