PHP adds watermark to png/jpg/gif format images

/**
* Add watermark to image (applicable to png/jpg/gif format)
* * @author flynetcn
* * @param $srcImg Original image
* @param $waterImg Watermark image
* @param $savepath Save path
* @param $savename Save name
* @param $positon Watermark position
* 1: Top left, 2: Top right, 3: Center, 4: Bottom left, 5: Bottom right
* @param $alpha Transparency -- 0 : Completely transparent, 100: Completely opaque*
* @return Success--new image address after adding watermark
* Failure---1: ​​The original file does not exist, -2: The watermark image does not exist, -3: The original file image Object creation failed -4: Watermark file image object creation failed, -5: New watermarked image failed to save
*/
function img_water_mark($srcImg, $waterImg, $savepath=null, $savename=null, $positon=5, $alpha=30) {
 $temp = pathinfo($srcImg);
$name = $temp['basename'];
$path = $temp['dirname'];
$exte = $temp['extension'];
$savename = $ savename ? $savename : $name;
$savepath = $savepath ? $savepath : $path;
$savefile = $savepath .'/'. $savename;
$srcinfo = @getimagesize($srcImg);
if (! $srcinfo) {
return -1; //The original file does not exist
}
$waterinfo = @getimagesize($waterImg);
if (!$waterinfo) {
return -2; //The watermark image does not exist
}
 $srcImgObj = image_create_from_ext($srcImg);
if (!$srcImgObj) {
return -3; //Failed to create original file image object
}
$waterImgObj = image_create_from_ext($waterImg);
if (!$waterImgObj) {
return -4; //Creation of watermark file image object failed
} switch ($positon) {
//1 Top is on the left
case 1: $x=$y=0; break;
//2 Top is on the right
case 2: $x = $srcinfo[0]-$waterinfo[0]; $y = 0; break;
//3 centered
case 3: $x = ($srcinfo[0]-$waterinfo[0])/ 2; $y = ($srcinfo[1]-$waterinfo[1])/2; break; //4 bottom left case 4: $x = 0; $y = $srcinfo[1]-$waterinfo[1] ; break; //5 bottom right case 5: $x = $srcinfo[0]-$waterinfo[0]; $y = $srcinfo[1]-$waterinfo[1]; break; default: $x=$ y=0; } imagecopymerge($srcImgObj, $waterImgObj, $x, $y, 0, 0, $waterinfo[0], $waterinfo[1], $alpha);
switch ($srcinfo[2]) {
 case 1: imagegif($srcImgObj, $savefile); break;
case 2: imagejpeg($srcImgObj, $savefile); break;
case 3: imagepng($srcImgObj, $savefile); break;
default: return -5 ; //Save failed
}
imagedestroy($srcImgObj);
imagedestroy($waterImgObj);
return $savefile; } function image_create_from_ext($imgfile) {
$info = getimagesize($imgfile);
$im = null; switch ($info[2]) {
case 1: $im=imagecreatefromgif($imgfile); break;
case 2: $im=imagecreatefromjpeg($imgfile); break;
case 3: $im=imagecreatefrompng($imgfile ); break;
}
return $im;
} ?>