利用PHP实现图片特效的方法总结

// 设置剪裁后的尺寸
$width = 200;
$height = 200;

// 创建一个指定尺寸的画布
$canvas = imagecreatetruecolor($width, $height);

// 从原始图片中剪裁所需区域
$source_image = imagecreatefromjpeg('source.jpg');
imagecopyresampled($canvas, $source_image, 0, 0, 0, 0, $width, $height, imagesx($source_image), imagesy($source_image));

// 将剪裁后的图片保存到文件
imagejpeg($canvas, 'cropped.jpg');

// 释放内存
imagedestroy($canvas);
imagedestroy($source_image);

// 设置缩放后的尺寸
$width = 500;
$height = 500;

// 创建一个指定尺寸的画布
$canvas = imagecreatetruecolor($width, $height);

// 缩放原始图片到目标尺寸
$source_image = imagecreatefromjpeg('source.jpg');
imagecopyresampled($canvas, $source_image, 0, 0, 0, 0, $width, $height, imagesx($source_image), imagesy($source_image));

// 将缩放后的图片保存到文件
imagejpeg($canvas, 'resized.jpg');

// 释放内存
imagedestroy($canvas);
imagedestroy($source_image);

// 创建一个原始图片副本
$source_image = imagecreatefromjpeg('source.jpg');
$filtered_image = imagecreatetruecolor(imagesx($source_image), imagesy($source_image));

// 应用滤镜效果
imagefilter($source_image, IMG_FILTER_GRAYSCALE);
imagecopy($filtered_image, $source_image, 0, 0, 0, 0, imagesx($source_image), imagesy($source_image));

// 将滤镜处理后的图片保存到文件
imagejpeg($filtered_image, 'filtered.jpg');

// 释放内存
imagedestroy($source_image);
imagedestroy($filtered_image);

// 创建一个原始图片副本
$source_image = imagecreatefromjpeg('source.jpg');

// 设置水印文字和字体大小
$text = 'Watermark';
$font_size = 20;

// 设置水印文字颜色
$red = 255;
$green = 255;
$blue = 255;
$text_color = imagecolorallocate($source_image, $red, $green, $blue);

// 在图片上添加水印文字
imagettftext($source_image, $font_size, 0, 10, 50, $text_color, 'arial.ttf', $text);

// 将带有水印的图片保存到文件
imagejpeg($source_image, 'watermarked.jpg');

// 释放内存
imagedestroy($source_image);