PHP如何实现图片处理_PHP图片处理功能的实现方法与代码实例

// 原图路径
$source = 'original.jpg';
// 获取原图信息// 设置缩略图最大宽高
$max_width = 200;
$max_height = 200;
// 计算缩放比例
$ratio = min($max_width / $width, $max_height / $height);
$new_width = (int)($width * $ratio);
$new_height = (int)($height * $ratio);
// 创建新图像资源
$thumb = imagecreatetruecolor($new_width, $new_height);
// 根据格式加载原图
$image = imagecreatefromjpeg($source);
// 缩放复制
imagecopyresampled($thumb, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
// 输出到文件
imagejpeg($thumb, 'thumb.jpg', 80); // 质量 80%
// 释放内存
imagedestroy($thumb);
imagedestroy($image);
?>

$img = 'photo.jpg';
$image = imagecreatefromjpeg($img);
$width = imagesx($image);
$height = imagesy($image);
// 水印文字
$text = '© MySite';
$font_size = 16;
$font_color = imagecolorallocate($image, 255, 255, 255); // 白色
// 计算文字位置
$bbox = imagettfbbox($font_size, 0, 'arial.ttf', $text);
$text_width = $bbox[2] - $bbox[0];
$text_height = $bbox[7] - $bbox[1];
$x = $width - $text_width - 10;
$y = $height - $text_height - 10;
// 添加文字
imagettftext($image, $font_size, 0, $x, $y, $font_color, 'arial.ttf', $text);
// 保存结果
imagejpeg($image, 'watermarked.jpg');
imagedestroy($image);
?>

$jpg_image = imagecreatefromjpeg('input.jpg');
imagepng($jpg_image, 'output.png');
imagedestroy($jpg_image);
?>

$src = 'photo.jpg';
$image = imagecreatefromjpeg($src);
// 裁剪参数：x, y, 宽, 高
$crop_x = 50;
$crop_y = 50;
$crop_width = 200;
$crop_height = 200;
$cropped = imagecreatetruecolor($crop_width, $crop_height);
imagecopy($cropped, $image, 0, 0, $crop_x, $crop_y, $crop_width, $crop_height);
imagejpeg($cropped, 'cropped.jpg');
imagedestroy($image);
imagedestroy($cropped);
?>