在PHP中如何使用imageaffinematrixget函數？基礎用法及詳細介紹

gitbox 2025-09-19

2. 基本用法示例

2.1 平移圖像

<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">// 獲取平移矩陣</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">// 應用矩陣到圖像</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">// 輸出結果</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>

上述代碼將圖像向右移動50像素、向下移動30像素。

2.2 縮放圖像

<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">// 獲取縮放矩陣</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">// 應用矩陣到圖像</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>

此代碼將圖像水平放大1.5倍，垂直縮小到0.8倍。

2.3 旋轉圖像

<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">// 獲取旋轉矩陣</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>

這裡將圖像順時針旋轉45度。

3. 高級用法

3.1 矩陣組合

有時候，我們需要對圖像同時進行縮放和旋轉，可以使用imageaffinematrixconcat來組合矩陣：

 <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 注意事項

矩陣的應用可能會導致圖像邊緣裁剪，可以使用imageaffine的$clip參數調整輸出尺寸。
imageaffinematrixget返回的矩陣必須使用浮點數，否則可能出現意想不到的結果。
矩陣順序很重要：先縮放再旋轉與先旋轉再縮放結果不同。