php 如何扭曲图像

<?php
// 创建一个图像资源
$image = imagecreatetruecolor(300, 300);

// 设置背景颜色
$bgColor = imagecolorallocate($image, 255, 255, 255);
imagefill($image, 0, 0, $bgColor);

// 加载要扭曲的图像
$sourceImage = imagecreatefromjpeg('source.jpg');
$sourceWidth = imagesx($sourceImage);
$sourceHeight = imagesy($sourceImage);

// 计算扭曲参数
$centerX = $sourceWidth / 2;
$centerY = $sourceHeight / 2;
$radius = min($sourceWidth, $sourceHeight) / 2;

// 扭曲图像
for ($x = 0; $x < $sourceWidth; $x++) {
    for ($y = 0; $y < $sourceHeight; $y++) {
        $dx = $x - $centerX;
        $dy = $y - $centerY;
        $distance = sqrt($dx * $dx + $dy * $dy);
        if ($distance < $radius) {
            $angle = atan2($dy, $dx);
            $newX = $centerX + $radius * cos($angle + $distance / 100);
            $newY = $centerY + $radius * sin($angle + $distance / 100);
            $color = imagecolorat($sourceImage, $newX, $newY);
            imagesetpixel($image, $x, $y, $color);
        }
    }
}

// 输出图像
header('Content-Type: image/jpeg');
imagejpeg($image);

// 释放内存
imagedestroy($image);
imagedestroy($sourceImage);
?>