一个修改自网上的高质量缩略图生成函数，效果可以看本站相册
高质量缩略图函数源码下载
http://www.dayanmei.com/download.php?filename=resizeimage.rar
可以按比例生成缩略图
<?php
define("GIF",1);
define("JPG",2);
define("PNG",3);
/**
$src_file sourse file
$dest_file dest file
$new_size array('width'=>?,'height'=?)
$quantity the quantity of desc
$method gd1.0 or gd2.0
**/
function ResizeImage($src_file="", $dest_file="", $new_size=array('width'=>100,'height'=>78), $quantity="80",$method="gd2")
{
//get infomation of iamge
/*
0 => width
1 => height
2 => 1 = GIF，2 = JPG，3 = PNG，4 = SWF，5 = PSD，6 = BMP，7 = TIFF(intel byte order)，8 = TIFF(motorola byte order)，9 = JPC，10 = JP2，11 = JPX，12 = JB2，13 = SWC，14 = IFF，15 = WBMP，16 = XBM
3 => height="yyy" width="xxx"
*/
$imginfo = getimagesize($src_file);
if ($imginfo == null)
return false;
// GD can only handle JPG & PNG images
if ($imginfo[2] != JPG && $imginfo[2] != PNG && $inginfo[2] != GIF && ($method == 'gd1' || $method == 'gd2')){
die("file is not be supported");
return false;
}
$srcWidth = $imginfo[0];
$srcHeight = $imginfo[1];
$radio=max(($srcWidth/$new_size['width']),($srcHeight/$new_size['height']));
$destWidth=(int)$srcWidth/$radio;
$destHeight=(int)$srcHeight/$radio;
switch ($method) {
case "gd1" :
if (!function_exists('imagecreatefromjpeg')) {
die("PHP running on your server does not support the GD image library");
}
if ($imginfo[2] == JPG)
$src_img = imagecreatefromjpeg($src_file);
elseif($imginfo[2] == PNG)
$src_img = imagecreatefrompng($src_file);
else $src_img = imagecreatefromgif($src_file);
if (!$src_img){
return false;
}
$dst_img = imagecreate($destWidth, $destHeight);
imagecopyresized($dst_img, $src_img, 0, 0, 0, 0, $destWidth, (int)$destHeight, $srcWidth, $srcHeight);
imagejpeg($dst_img, $dest_file, $quantity);
imagedestroy($src_img);
imagedestroy($dst_img);
break;
case "gd2" :
// check if support GD2
if (!function_exists('imagecreatefromjpeg')) {
die("PHP running on your server does not support the GD image library");
}
if (!function_exists('imagecreatetruecolor')) {
die("PHP running on your server does not support GD version 2.x, please change to GD version 1.x on your method");
}
if ($imginfo[2] == JPG)
$src_img = imagecreatefromjpeg($src_file);
elseif($imginfo[2] == PNG)
$src_img = imagecreatefrompng($src_file);
else $src_img = imagecreatefromgif($src_file);
if (!$src_img){
return false;
}
$dst_img = imagecreatetruecolor($destWidth, $destHeight);
imagecopyresampled($dst_img, $src_img, 0, 0, 0, 0, $destWidth, (int)$destHeight, $srcWidth, $srcHeight);
imagejpeg($dst_img, $dest_file, $quantity);
imagedestroy($src_img);
imagedestroy($dst_img);
break;
}
// Set mode of uploaded picture
chmod($dest_file, 0755);
// We check that the image is valid
$imginfo = @getimagesize($dest_file);
if ($imginfo == null){
@unlink($dest_file);
return false;
} else {
return true;
}
}
?>
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