在PHP中如何使用imageaffinematrixget函数？基础用法及详细介绍

gitbox 2025-09-19

2. 基本用法示例

2.1 平移图像

<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-variable">$image</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecreatefromjpeg</span></span><span>(</span><span><span class="hljs-string">'example.jpg'</span></span><span>);

</span><span><span class="hljs-comment">// 获取平移矩阵</span></span><span>
</span><span><span class="hljs-variable">$matrix</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffinematrixget</span></span><span>(IMG_AFFINE_TRANSLATE, [</span><span><span class="hljs-string">'x'</span></span><span> =&gt; </span><span><span class="hljs-number">50</span></span><span>, </span><span><span class="hljs-string">'y'</span></span><span> =&gt; </span><span><span class="hljs-number">30</span></span><span>]);

</span><span><span class="hljs-comment">// 应用矩阵到图像</span></span><span>
</span><span><span class="hljs-variable">$translated</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffine</span></span><span>(</span><span><span class="hljs-variable">$image</span></span><span>, </span><span><span class="hljs-variable">$matrix</span></span><span>);

</span><span><span class="hljs-comment">// 输出结果</span></span><span>
</span><span><span class="hljs-title function_ invoke__">header</span></span><span>(</span><span><span class="hljs-string">'Content-Type: image/jpeg'</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagejpeg</span></span><span>(</span><span><span class="hljs-variable">$translated</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$image</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$translated</span></span><span>);
</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>

上述代码将图像向右移动50像素、向下移动30像素。

2.2 缩放图像

<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-variable">$image</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecreatefromjpeg</span></span><span>(</span><span><span class="hljs-string">'example.jpg'</span></span><span>);

</span><span><span class="hljs-comment">// 获取缩放矩阵</span></span><span>
</span><span><span class="hljs-variable">$matrix</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffinematrixget</span></span><span>(IMG_AFFINE_SCALE, [</span><span><span class="hljs-string">'x'</span></span><span> =&gt; </span><span><span class="hljs-number">1.5</span></span><span>, </span><span><span class="hljs-string">'y'</span></span><span> =&gt; </span><span><span class="hljs-number">0.8</span></span><span>]);

</span><span><span class="hljs-comment">// 应用矩阵到图像</span></span><span>
</span><span><span class="hljs-variable">$scaled</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffine</span></span><span>(</span><span><span class="hljs-variable">$image</span></span><span>, </span><span><span class="hljs-variable">$matrix</span></span><span>);

</span><span><span class="hljs-title function_ invoke__">header</span></span><span>(</span><span><span class="hljs-string">'Content-Type: image/jpeg'</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagejpeg</span></span><span>(</span><span><span class="hljs-variable">$scaled</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$image</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$scaled</span></span><span>);
</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>

此代码将图像水平放大1.5倍，垂直缩小到0.8倍。

2.3 旋转图像

<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-variable">$image</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecreatefromjpeg</span></span><span>(</span><span><span class="hljs-string">'example.jpg'</span></span><span>);

</span><span><span class="hljs-comment">// 获取旋转矩阵</span></span><span>
</span><span><span class="hljs-variable">$matrix</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffinematrixget</span></span><span>(IMG_AFFINE_ROTATE, [</span><span><span class="hljs-string">'angle'</span></span><span> =&gt; </span><span><span class="hljs-number">45</span></span><span>]);

</span><span><span class="hljs-variable">$rotated</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffine</span></span><span>(</span><span><span class="hljs-variable">$image</span></span><span>, </span><span><span class="hljs-variable">$matrix</span></span><span>);

</span><span><span class="hljs-title function_ invoke__">header</span></span><span>(</span><span><span class="hljs-string">'Content-Type: image/jpeg'</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagejpeg</span></span><span>(</span><span><span class="hljs-variable">$rotated</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$image</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$rotated</span></span><span>);
</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>

这里将图像顺时针旋转45度。

3. 高级用法

3.1 矩阵组合

有时候，我们需要对图像同时进行缩放和旋转，可以使用 imageaffinematrixconcat 来组合矩阵：

<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-variable">$scale</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffinematrixget</span></span><span>(IMG_AFFINE_SCALE, [</span><span><span class="hljs-string">'x'</span></span><span> =&gt; </span><span><span class="hljs-number">2.0</span></span><span>, </span><span><span class="hljs-string">'y'</span></span><span> =&gt; </span><span><span class="hljs-number">2.0</span></span><span>]);
</span><span><span class="hljs-variable">$rotate</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffinematrixget</span></span><span>(IMG_AFFINE_ROTATE, [</span><span><span class="hljs-string">'angle'</span></span><span> =&gt; </span><span><span class="hljs-number">30</span></span><span>]);

</span><span><span class="hljs-variable">$combined</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffinematrixconcat</span></span><span>(</span><span><span class="hljs-variable">$scale</span></span><span>, </span><span><span class="hljs-variable">$rotate</span></span><span>);

</span><span><span class="hljs-variable">$transformed</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imageaffine</span></span><span>(</span><span><span class="hljs-variable">$image</span></span><span>, </span><span><span class="hljs-variable">$combined</span></span><span>);
</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>

3.2 注意事项

矩阵的应用可能会导致图像边缘裁剪，可以使用 imageaffine 的 $clip 参数调整输出尺寸。
imageaffinematrixget 返回的矩阵必须使用浮点数，否则可能出现意想不到的结果。
矩阵顺序很重要：先缩放再旋转与先旋转再缩放结果不同。