PHP图片裁剪、缩放函数

根据自定义的目标图高宽, 按目标图高宽比裁剪、缩放源图.

传入参数:
$source_path string 源图路径
$target_width integer 目标图宽度
$target_height integer 目标图高度

源图支持MIMETYPE: image/gif, image/jpeg, image/png.

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);

header(‘Content-Type: image/jpeg’);
imagejpeg($target_image);
imagedestroy($source_image);
imagedestroy($target_image);
imagedestroy($cropped_image);
}

 

原文地址： http://www.php100.com/html/php/hanshu/2013/1025/6320.html