php 图像裁剪(自定义裁剪图片大小)

<?php
/**
* 图像裁剪
* @param $title string 原图路径
* @param $content string 需要裁剪的宽
* @param $encode string 需要裁剪的高
*/
function imagecropper($source_path, $target_width, $target_height)
{
$source_info = getimagesize($source_path);
$source_width = $source_info[0];
$source_height = $source_info[1];
$source_mime = $source_info['mime'];
$source_ratio = $source_height / $source_width;
$target_ratio = $target_height / $target_width;

// 源图过高
if ($source_ratio > $target_ratio)
{
$cropped_width = $source_width;
$cropped_height = $source_width * $target_ratio;
$source_x = 0;
$source_y = ($source_height - $cropped_height) / 2;
}
// 源图过宽
elseif ($source_ratio < $target_ratio)
{
$cropped_width = $source_height / $target_ratio;
$cropped_height = $source_height;
$source_x = ($source_width - $cropped_width) / 2;
$source_y = 0;
}
// 源图适中
else
{
$cropped_width = $source_width;
$cropped_height = $source_height;
$source_x = 0;
$source_y = 0;
}

switch ($source_mime)
{
case 'image/gif':
$source_image = imagecreatefromgif($source_path);
break;

case 'image/jpeg':
$source_image = imagecreatefromjpeg($source_path);
break;

case 'image/png':
$source_image = imagecreatefrompng($source_path);
break;

default:
return false;
break;
}

$target_image = imagecreatetruecolor($target_width, $target_height);
$cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);

// 裁剪
imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);
// 缩放
imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);

//保存图片到本地(两者选一)
//$randNumber = mt_rand(00000, 99999). mt_rand(000, 999);
//$fileName = substr(md5($randNumber), 8, 16) .".png";
//imagepng($target_image,'./'.$fileName);
//imagedestroy($target_image);

//直接在浏览器输出图片(两者选一)
header('Content-Type: image/jpeg');
imagepng($target_image);
imagedestroy($target_image);
imagejpeg($target_image);
imagedestroy($source_image);
imagedestroy($target_image);
imagedestroy($cropped_image);
}

//调用
//imagecropper('./img033.jpg',300,300);
imagecropper('./img033.jpg',140,140);
//imagecropper('./img033.jpg',55,55);
?>