本文实例讲述了php实现按指定大小等比缩放生成上传图片缩略图的方法。分享给大家供大家参考。具体实现方法如下：

复制代码 代码如下:/**

* *

*等比缩放

* @param unknown_type $srcImage 源图片路径

* @param unknown_type $toFile 目标图片路径

* @param unknown_type $maxWidth 最大宽

* @param unknown_type $maxHeight 最大高

* @param unknown_type $imgQuality 图片质量

* @return unknown

*/

function resize($srcImage,$toFile,$maxWidth = 100,$maxHeight = 100,$imgQuality=100)

{

list($width, $height, $type, $attr) = getimagesize($srcImage);

if($width < $maxWidth || $height < $maxHeight) return ;

switch ($type) {

case 1: $img = imagecreatefromgif($srcImage); break;

case 2: $img = imagecreatefromjpeg($srcImage); break;

case 3: $img = imagecreatefrompng($srcImage); break;

}

$scale = min($maxWidth/$width, $maxHeight/$height); //求出绽放比例

if($scale < 1) {

$newWidth = floor($scale*$width);

$newHeight = floor($scale*$height);

$newImg = imagecreatetruecolor($newWidth, $newHeight);

imagecopyresampled($newImg, $img, 0, 0, 0, 0, $newWidth, $newHeight, $width, $height);

$newName = "";

$toFile = preg_replace("/(.gif|.jpg|.jpeg|.png)/i","",$toFile);

switch($type) {

case 1: if(imagegif($newImg, "$toFile$newName.gif", $imgQuality))

return "$newName.gif"; break;

case 2: if(imagejpeg($newImg, "$toFile$newName.jpg", $imgQuality))

return "$newName.jpg"; break;

case 3: if(imagepng($newImg, "$toFile$newName.png", $imgQuality))

return "$newName.png"; break;

default: if(imagejpeg($newImg, "$toFile$newName.jpg", $imgQuality))

return "$newName.jpg"; break;

}

imagedestroy($newImg);

}

imagedestroy($img);

return false;

}

希望本文所述对大家的PHP程序设计有所帮助。