PHP按最大宽高缩略图片函数代码

很简单的按照最大宽高来缩略图片的代码，方便新手和懒得自己写的人

1. function thumb($imagefile, $maxwidth, $maxheight) {
2. $dim = getimagesize($imagefile);
3. $width = $dim[0]; //原图宽度
4. $height = $dim[1]; //原图高度
5. $original = imagecreatefromjpeg($imagefile);
7. $thcrown = $maxwidth/$maxheight; //缩略图最大宽度与最大高度比
8. $crown = $width/$height; //原图宽高比
9. if($crown/$thcrown >= 1){
10. $thumbWidth = $maxwidth;
11. $thumbHeight = $maxwidth/$crown;
12. } else {
13. $thumbHeight = $maxheight;
14. $thumbWidth = $maxheight*$crown;
15. }
17. $thumb = imagecreatetruecolor($thumbWidth, $thumbHeight);
18. imagecopyresampled($thumb, $original, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $width, $height);
19. return $thumb;
20. }

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