中文(繁體)
中文(繁體)
<span><span><span class="hljs-meta"><?php</span></span><span>
<span class="hljs-comment">/*
本示例文章將介紹如何將 imagepalettecopy 與 imagecreate 函數結合使用，
并通过实例代码展示其應用場景與技巧。
*/</span>
</span><span><span class="hljs-meta">?></span></span><span>
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</span><span><span class="hljs-comment"># 如何將 imagepalettecopy 與 imagecreate 函數結合使用？實用示例分享</span></span><span>
</span><span><span class="hljs-comment">## 一、`imagecreate` 與 `imagepalettecopy` 簡介</span></span><span>
- **`</span><span><span class="hljs-title function_ invoke__">imagecreate</span></span><span>(</span><span><span class="hljs-keyword">int</span></span><span> </span><span><span class="hljs-variable">$width</span></span><span>, </span><span><span class="hljs-keyword">int</span></span><span> </span><span><span class="hljs-variable">$height</span></span><span>)`**
用於創建一個基於調色板的圖像（索引顏色圖像），適合對顏色數量有限的圖片進行處理。
返回值是一個圖像資源句柄。
- **`</span><span><span class="hljs-title function_ invoke__">imagepalettecopy</span></span><span>(resource </span><span><span class="hljs-variable">$dst</span></span><span>, resource </span><span><span class="hljs-variable">$src</span></span><span>)`**
</span><span><span class="hljs-comment">## 二、應用場景</span></span><span>
</span><span><span class="hljs-number">1</span></span><span>. **批量生成相同風格的縮略圖**
</span><span><span class="hljs-number">2</span></span><span>. **索引圖像的調色板同步**
如果多個索引圖像需要在後續合併或比較顏色，調色板保持一致非常重要。
</span><span><span class="hljs-comment">## 三、代碼示例</span></span><span>
```php
</span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 創建源圖像（索引顏色）</span></span><span>
</span><span><span class="hljs-variable">$src</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecreate</span></span><span>(</span><span><span class="hljs-number">200</span></span><span>, </span><span><span class="hljs-number">200</span></span><span>);
</span><span><span class="hljs-variable">$red</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecolorallocate</span></span><span>(</span><span><span class="hljs-variable">$src</span></span><span>, </span><span><span class="hljs-number">255</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>);
</span><span><span class="hljs-variable">$green</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecolorallocate</span></span><span>(</span><span><span class="hljs-variable">$src</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">255</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>);
</span><span><span class="hljs-variable">$blue</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecolorallocate</span></span><span>(</span><span><span class="hljs-variable">$src</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">255</span></span><span>);
</span><span><span class="hljs-comment">// 用紅色填充背景</span></span><span>
</span><span><span class="hljs-title function_ invoke__">imagefill</span></span><span>(</span><span><span class="hljs-variable">$src</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-variable">$red</span></span><span>);
</span><span><span class="hljs-comment">// 創建目標圖像（索引顏色）</span></span><span>
</span><span><span class="hljs-variable">$dst</span></span><span> = </span><span><span class="hljs-title function_ invoke__">imagecreate</span></span><span>(</span><span><span class="hljs-number">200</span></span><span>, </span><span><span class="hljs-number">200</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagepalettecopy</span></span><span>(</span><span><span class="hljs-variable">$dst</span></span><span>, </span><span><span class="hljs-variable">$src</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagefill</span></span><span>(</span><span><span class="hljs-variable">$dst</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-variable">$blue</span></span><span>);
</span><span><span class="hljs-comment">// 輸出圖片進行對比</span></span><span>
</span><span><span class="hljs-title function_ invoke__">header</span></span><span>(</span><span><span class="hljs-string">"Content-Type: image/png"</span></span><span>);
</span><span><span class="hljs-comment">// 這裡只輸出目標圖像，你可以根據需要保存兩個圖像進行查看</span></span><span>
</span><span><span class="hljs-title function_ invoke__">imagepng</span></span><span>(</span><span><span class="hljs-variable">$dst</span></span><span>);
</span><span><span class="hljs-comment">// 釋放資源</span></span><span>
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$src</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">imagedestroy</span></span><span>(</span><span><span class="hljs-variable">$dst</span></span><span>);
</span><span><span class="hljs-meta">?></span></span><span>
</span></span>通過imagecreate與imagepalettecopy的結合，我們可以方便地在多個索引圖像間共享相同的調色板，避免了手動分配相同顏色的重複工作。在批量處理、調色板同步、保持視覺統一等場景中，這種方法都非常實用。掌握這些函數的用法，將有助於我們在PHP 圖像處理項目中更高效地管理顏色數據。
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