php缩略图代码，imagecopyresampled函数生成缩略图

function CreateImage($SrcImageUrl, $DirImageUrl, $Width, $Height)

$srcw = imagesx($img);

if ($srcw / $srch > $Width / $Height)

$new_image = imagecreatetruecolor($new_width, $new_height);

imagedestroy($img);

/*

*$o_photo 原图路径

*$d_photo 处理后图片路径

*$width 定义宽

*$height 定义高

*调用方法 cutphoto("test.jpg","temp.jpg",256,146);

*/

function cutphoto($o_photo,$d_photo,$width,$height){

$temp_img = imagecreatefromjpeg($o_photo);

$o_width = imagesx($temp_img); //取得原图宽

$o_height = imagesy($temp_img); //取得原图高

//判断处理方法

if($width>$o_width || $height>$o_height){//原图宽或高比规定的尺寸小,进行压缩

$newwidth=$o_width;

$newheight=$o_height;

if($o_width>$width){

$newwidth=$width;

$newheight=$o_height*$width/$o_width;

}

if($newheight>$height){

$newwidth=$newwidth*$height/$newheight;

$newheight=$height;

}

//缩略图片

$new_img = imagecreatetruecolor($newwidth, $newheight);

imagecopyresampled($new_img, $temp_img, 0, 0, 0, 0, $newwidth, $newheight, $o_width, $o_height);

imagejpeg($new_img , $d_photo);

imagedestroy($new_img);

}else{//原图宽与高都比规定尺寸大,进行压缩后裁剪

if($o_height*$width/$o_width>$height){//先确定width与规定相同,如果height比规定大,则ok

$newwidth=$width;

$newheight=$o_height*$width/$o_width;

$x=0;

$y=($newheight-$height)/2;

}else{ //否则确定height与规定相同,width自适应

$newwidth=$o_width*$height/$o_height;

$newheight=$height;

$x=($newwidth-$width)/2;

$y=0;

}

//缩略图片

$new_img = imagecreatetruecolor($newwidth, $newheight);

imagecopyresampled($new_img, $temp_img, 0, 0, 0, 0, $newwidth, $newheight, $o_width, $o_height);

imagejpeg($new_img , $d_photo);

imagedestroy($new_img);

$temp_img = imagecreatefromjpeg($d_photo);

$o_width = imagesx($temp_img); //取得缩略图宽

$o_height = imagesy($temp_img); //取得缩略图高

//裁剪图片

$new_imgx = imagecreatetruecolor($width,$height);

imagecopyresampled($new_imgx,$temp_img,0,0,$x,$y,$width,$height,$width,$height);

imagejpeg($new_imgx , $d_photo);

imagedestroy($new_imgx);