PHP thumbnail code, imagecopyresampled function generates thumbnails

function CreateImage($SrcImageUrl, $DirImageUrl, $Width, $Height)
{
$img;
$srcw;
$new_width;
$srch;
$new_height;
// 图片类型
$type = substr(strrchr($SrcImageUrl, "."), 1);
// 初始化图像
if($type == "jpg")
$img = imagecreatefromjpeg($SrcImageUrl);
if($type == "gif")
$img = imagecreatefromgif($SrcImageUrl);
if($type == "png")
$img = imagecreatefrompng($SrcImageUrl);
$srcw = imagesx($img);
$srch = imagesy($img);
if ($srcw / $srch > $Width / $Height)
{
if ($srcw > $Width)
{
$new_width = $Width;
$new_height = $srch * ($Width / $srcw);
}
else
{
$new_width = $srcw;
$new_height = $srch;
}
}
else
{
if ($srch > $Height)
{
$new_height = $Height;
$new_width = $srcw * ($Height / $srch);
}
else
{
$new_width = $srcw;
$new_height = $srch;
}
}
$new_image = imagecreatetruecolor($new_width, $new_height);
imagecopyresampled($new_image, $img, 0, 0, 0, 0, $new_width, $new_height, $srcw, $srch);
imagejpeg($new_image, $DirImageUrl);
imagedestroy($img);
imagedestroy($new_image);
}

3. Improved code:

/*
*$o_photo Original image path
*$d_photo Processed image Path
*$width Define width
*$height Define height
*Call method cutphoto("test.jpg ","temp.jpg",256,146);
*/
function cutphoto($o_photo,$d_photo,$width,$height){< ;/p>
$temp_img = imagecreatefromjpeg($o_photo);
$o_width = imagesx($temp_img); //Get the original image width
< ;p>$o_height = imagesy($temp_img); //Get the original image height
//Judge the processing method
if($width>$o_width || $height>$o_height){//The width or height of the original image is smaller than the specified size, and is compressed
$newwidth=$o_width;
 $newheight=$o_height;
if($o_width>$width){
$newwidth=$width;

}
if($newheight>$height){
< ;p>$newwidth=$newwidth*$height/$newheight;
$newheight=$height;
}
< p>//Thumbnail image
$new_img = imagecreatetruecolor($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{//The original image width and height are larger than the specified size, compress and then crop
if($o_height*$width /$o_width>$height){//First make sure the width is the same as the specification. If the height is larger than the specification, then ok
$newwidth=$width;
 $newheight=$o_height*$width/$o_width;
$x=0;
$y=($newheight-$height)/2;
}else{ // Otherwise, make sure the height is the same as specified, and the width is adaptive
$newwidth=$o_width*$height/$o_height;
$newheight=$height;
$x=($newwidth-$width)/2;
$y=0 ;
}
//Thumbnail image
$new_img = imagecreatetruecolor($newwidth, $newheight);< ;/p>
imagecopyresampled($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);
< p>$o_width = imagesx($temp_img); //Get the thumbnail width
$o_height = imagesy($temp_img); //Get the thumbnail height
< p>//Crop the image
$new_imgx = imagecreatetruecolor($width,$height);
imagecopyresampled($new_imgx,$temp_img,0,0, $x,$y,$width,$height,$width,$height);
imagejpeg($new_imgx , $d_photo);
imagedestroy( $new_imgx);
}
}
?>