PHP 函数在图像处理中的应用

imagecopyresized($dst_image, $src_image, 0, 0, 0, 0, 200, 100, 500, 250);

imagecrop($image, ['x' => 100, 'y' => 100, 'width' => 200, 'height' => 200]);

imagerotate($image, 45, 0);

imagecopymerge($dst_image, $watermark, 10, 10, 0, 0, 50, 50, 50);

function createThumbnail($filename, $width, $height)
{
    // 获取原始图像的信息
    list($originalWidth, $originalHeight) = getimagesize($filename);

    // 计算缩放比例
    $scaleX = $width / $originalWidth;
    $scaleY = $height / $originalHeight;

    // 创建一个新图像（透明的）
    $thumb = imagecreatetruecolor($width, $height);
    imagealphablending($thumb, false);
    imagesavealpha($thumb, true);

    // 保存缩略图
    switch (pathinfo($filename, PATHINFO_EXTENSION)) {
        case 'png':
            imagepng($thumb, $filename);
            break;
        case 'jpeg':
        case 'jpg':
            imagejpeg($thumb, $filename, 90);
            break;
    }
}