php 等比例缩放图片

<?php
function resizeImage($source, $destination, $width, $height) {
    $image = imagecreatefromjpeg($source);
    $originalWidth = imagesx($image);
    $originalHeight = imagesy($image);

    if ($originalWidth > $originalHeight) {
        // 如果原图宽大于高，则以宽度为准进行缩放
        $newWidth = $width;
        $newHeight = intval($originalHeight * $width / $originalWidth);
    } else {
        // 如果原图高大于宽，则以高度为准进行缩放
        $newHeight = $height;
        $newWidth = intval($originalWidth * $height / $originalHeight);
    }

    $newImage = imagecreatetruecolor($newWidth, $newHeight);
    imagecopyresampled($newImage, $image, 0, 0, 0, 0, $newWidth, $newHeight, $originalWidth, $originalHeight);

    imagejpeg($newImage, $destination);
    imagedestroy($image);
    imagedestroy($newImage);
}

// 使用示例
$source = 'path/to/source/image.jpg';
$destination = 'path/to/destination/image.jpg';
$width = 300;
$height = 200;

resizeImage($source, $destination, $width, $height);
?>