php生成缩略图的类代码

<?php

/**
* 功能:生成缩略图
* 作者:phpox
* 日期:thu may 17 09:57:05 cst 2007
*/

class creatminiature
{
//公共变量
var $srcfile=""; //原图
var $echotype; //输出图片类型，link--不保存为文件；file--保存为文件
var $im=""; //临时变量
var $srcw=""; //原图宽
var $srch=""; //原图高

//设置变量及初始化
function setvar($srcfile,$echotype)
{
if (!file_exists($srcfile)){
echo '源图片文件不存在!';
exit();
}
$this->srcfile=$srcfile;
$this->echotype=$echotype;

$info = "";
$data = getimagesize($this->srcfile,$info);
switch ($data[2])
{
case 1:
if(!function_exists("imagecreatefromgif")){
echo "你的gd库不能使用gif格式的图片，请使用jpeg或png格式！<a href='javascript:go(-1);'>返回</a>";
exit();
}
$this->im = imagecreatefromgif($this->srcfile);
break;
case 2:
if(!function_exists("imagecreatefromjpeg")){
echo "你的gd库不能使用jpeg格式的图片，请使用其它格式的图片！<a href='javascript:go(-1);'>返回</a>";
exit();
}
$this->im = imagecreatefromjpeg($this->srcfile);
break;
case 3:
$this->im = imagecreatefrompng($this->srcfile);
break;
}
$this->srcw=imagesx($this->im);
$this->srch=imagesy($this->im);
}

//生成扭曲型缩图
function distortion($tofile,$tow,$toh)
{
$cimg=$this->creatimage($this->im,$tow,$toh,0,0,0,0,$this->srcw,$this->srch);
return $this->echoimage($cimg,$tofile);
imagedestroy($cimg);
}

//生成按比例缩放的缩图
function prorate($tofile,$tow,$toh)
{
$towh=$tow/$toh;
$srcwh=$this->srcw/$this->srch;
if($towh<=$srcwh)
{
$ftow=$tow;
$ftoh=$ftow*($this->srch/$this->srcw);
}
else
{
$ftoh=$toh;
$ftow=$ftoh*($this->srcw/$this->srch);
}
if($this->srcw>$tow||$this->srch>$toh)
{
$cimg=$this->creatimage($this->im,$ftow,$ftoh,0,0,0,0,$this->srcw,$this->srch);
return $this->echoimage($cimg,$tofile);
imagedestroy($cimg);
}
else
{
$cimg=$this->creatimage($this->im,$this->srcw,$this->srch,0,0,0,0,$this->srcw,$this->srch);
return $this->echoimage($cimg,$tofile);
imagedestroy($cimg);
}
}

//生成最小裁剪后的缩图
function cut($tofile,$tow,$toh)
{
$towh=$tow/$toh;
$srcwh=$this->srcw/$this->srch;
if($towh<=$srcwh)
{
$ctoh=$toh;
$ctow=$ctoh*($this->srcw/$this->srch);
}
else
{
$ctow=$tow;
$ctoh=$ctow*($this->srch/$this->srcw);
}
$allimg=$this->creatimage($this->im,$ctow,$ctoh,0,0,0,0,$this->srcw,$this->srch);
$cimg=$this->creatimage($allimg,$tow,$toh,0,0,($ctow-$tow)/2,($ctoh-$toh)/2,$tow,$toh);
return $this->echoimage($cimg,$tofile);
imagedestroy($cimg);
imagedestroy($allimg);
}

//生成背景填充的缩图
function backfill($tofile,$tow,$toh,$bk1=255,$bk2=255,$bk3=255)
{
$towh=$tow/$toh;
$srcwh=$this->srcw/$this->srch;
if($towh<=$srcwh)
{
$ftow=$tow;
$ftoh=$ftow*($this->srch/$this->srcw);
}
else
{
$ftoh=$toh;
$ftow=$ftoh*($this->srcw/$this->srch);
}
if(function_exists("imagecreatetruecolor"))
{
@$cimg=imagecreatetruecolor($tow,$toh);
if(!$cimg)
{
$cimg=imagecreate($tow,$toh);
}
}
else
{
$cimg=imagecreate($tow,$toh);
}
$backcolor = imagecolorallocate($cimg, $bk1, $bk2, $bk3); //填充的背景颜色
imagefilledrectangle($cimg,0,0,$tow,$toh,$backcolor);
if($this->srcw>$tow||$this->srch>$toh)
{
$proimg=$this->creatimage($this->im,$ftow,$ftoh,0,0,0,0,$this->srcw,$this->srch);
if($ftow<$tow)
{
imagecopy($cimg,$proimg,($tow-$ftow)/2,0,0,0,$ftow,$ftoh);
}
else if($ftoh<$toh)
{
imagecopy($cimg,$proimg,0,($toh-$ftoh)/2,0,0,$ftow,$ftoh);
}
else
{
imagecopy($cimg,$proimg,0,0,0,0,$ftow,$ftoh);
}
}
else
{
imagecopymerge($cimg,$this->im,($tow-$ftow)/2,($toh-$ftoh)/2,0,0,$ftow,$ftoh,100);
}
return $this->echoimage($cimg,$tofile);
imagedestroy($cimg);
}


function creatimage($img,$creatw,$creath,$dstx,$dsty,$srcx,$srcy,$srcimgw,$srcimgh)
{
if(function_exists("imagecreatetruecolor"))
{
@$creatimg = imagecreatetruecolor($creatw,$creath);
if($creatimg)
imagecopyresampled($creatimg,$img,$dstx,$dsty,$srcx,$srcy,$creatw,$creath,$srcimgw,$srcimgh);
else
{
$creatimg=imagecreate($creatw,$creath);
imagecopyresized($creatimg,$img,$dstx,$dsty,$srcx,$srcy,$creatw,$creath,$srcimgw,$srcimgh);
}
}
else
{
$creatimg=imagecreate($creatw,$creath);
imagecopyresized($creatimg,$img,$dstx,$dsty,$srcx,$srcy,$creatw,$creath,$srcimgw,$srcimgh);
}
return $creatimg;
}

//输出图片，link---只输出，不保存文件。file--保存为文件
function echoimage($img,$to_file)
{
switch($this->echotype)
{
case "link":
if(function_exists('imagejpeg')) return imagejpeg($img);
else return imagepng($img);
break;
case "file":
if(function_exists('imagejpeg')) return imagejpeg($img,$to_file);
else return imagepng($img,$to_file);
break;
}
}
}
?>