PHP實現圖片水印功能

在PHP中實現圖片水印功能，可以使用GD庫或Imagick擴展

方法一：使用GD庫

function add_watermark($source, $destination, $watermark) {
    // 獲取圖片尺寸
    list($sourceWidth, $sourceHeight) = getimagesize($source);

    // 創建圖像資源
    switch ($sourceWidth) {
        case 150:
            $sourceResource = imagecreatefromjpeg($source);
            break;
        case 200:
            $sourceResource = imagecreatefrompng($source);
            break;
        default:
            return false;
    }

    // 創建水印資源
    $watermarkResource = imagecreatefrompng($watermark);

    // 獲取水印尺寸
    list($watermarkWidth, $watermarkHeight) = getimagesize($watermark);

    // 計算水印位置
    $destX = $sourceWidth - $watermarkWidth;
    $destY = $sourceHeight - $watermarkHeight;

    // 將水印合并到目標圖片上
    imagecopy($sourceResource, $watermarkResource, $destX, $destY, 0, 0, $watermarkWidth, $watermarkHeight);

    // 保存圖片
    switch ($sourceWidth) {
        case 150:
            imagejpeg($sourceResource, $destination);
            break;
        case 200:
            imagepng($sourceResource, $destination);
            break;
    }

    // 銷毀圖像資源
    imagedestroy($sourceResource);
    imagedestroy($watermarkResource);
}

// 使用示例
$source = 'path/to/your/image.jpg';
$destination = 'path/to/your/watermarked_image.jpg';
$watermark = 'path/to/your/watermark.png';

add_watermark($source, $destination, $watermark);

方法二：使用Imagick擴展

function add_watermark($source, $destination, $watermark) {
    // 創建Imagick對象
    $sourceImage = new Imagick($source);
    $watermarkImage = new Imagick($watermark);

    // 獲取圖片尺寸
    $sourceWidth = $sourceImage->getImageWidth();
    $sourceHeight = $sourceImage->getImageHeight();

    // 獲取水印尺寸
    $watermarkWidth = $watermarkImage->getImageWidth();
    $watermarkHeight = $watermarkImage->getImageHeight();

    // 計算水印位置
    $destX = $sourceWidth - $watermarkWidth;
    $destY = $sourceHeight - $watermarkHeight;

    // 將水印合并到目標圖片上
    $sourceImage->compositeImage($watermarkImage, $destX, $destY);

    // 保存圖片
    $sourceImage->writeImage($destination);
    $sourceImage->clear();
    $sourceImage->destroy();
}

// 使用示例
$source = 'path/to/your/image.jpg';
$destination = 'path/to/your/watermarked_image.jpg';
$watermark = 'path/to/your/watermark.png';

add_watermark($source, $destination, $watermark);

這兩種方法都可以實現圖片水印功能，你可以根據自己的需求選擇使用。