Fusion of jpge and png pictures

The fusion of jpge images and png images is actually the watermark technology that everyone is familiar with. The most important sentence in the code below is:

//Set the color blending mode of the image
imagealphablending($ground_im, true);

/*
 * Function: PHP image watermark (watermark supports images or text)
 * Parameters:
 * $groundImage background image, that is, the image that needs to be watermarked, currently only supports GIF, JPG, PNG format;
 * $waterPos watermark position, there are 10 states, 0 is a random position;
 * 1 is the top left, 2 is the top center, 3 is the top right;
 * 4 is the middle left, 5 is the middle center, 6 means the middle is on the right;
 * 7 is on the bottom on the left, 8 is on the bottom in the center, 9 is on the bottom on the right;
 * $waterImage image watermark, that is, the image used as the watermark, currently only supports GIF, JPG, and PNG formats;
 * $waterText text watermark, that is, text is used as a watermark, supports ASCII code, does not support Chinese;
 * $textFont text size, the value is 1, 2, 3, 4 or 5, the default is 5;
 * $textColor text Color, the value is a hexadecimal color value, the default is #FF0000 (red);
 *
 * Note: Support GD 2.0, Support FreeType, GIF Read, GIF Create, JPG, PNG
 * $waterImage and $waterText are best Don't use them at the same time, just choose one of them, and use $waterImage first.
 * When $waterImage is valid, the parameters $waterString, $stringFont, and $stringColor are not valid.
 * The file name of the watermarked image is the same as $groundImage.
 * Author: longware @ 2004-11-3 14:15:13
 */

function imageWaterMark($groundImage,$waterPos=0,$waterImage="",$waterText="",$textFont=5,$ textColor="#FF0000")
//function imageWaterMark($groundImage,$waterPos=0,$waterImage,$waterText=,$textFont=5,$textColor=#FF0000″)
{
 $isWaterImage = FALSE;
 $ formatMsg = "This file format is not supported yet. Please use image processing software to convert the image to GIF, JPG, or PNG format.";
 //Read watermark file
 if(!empty($waterImage) && file_exists($waterImage))
 {
 $isWaterImage = TRUE;
 $water_info = getimagesize($waterImage);
 $water_w = $water_info[ 0];//Get the width of the watermark image
 $water_h = $water_info[1];//Get the height of the watermark image
 switch($water_info[2])//Get the format of the watermark image
 {
 case 1:$ water_im = imagecreatefromgif($waterImage);break;
 case 2:$water_im = imagecreatefromjpeg($waterImage);break;
 case 3:$water_im = imagecreatefrompng($waterImage);break;
 default:die($formatMsg);
 }
 }
 //Read? Chenbaji?
 if(!empty($groundImage) && file_exists($groundImage))
 {
 $ground_info = getimagesize($groundImage);
 $ground_w = $ground_info[0]; //Get the width of the background image
 $ground_h = $ground_info[1];//Get the height of the background image
 switch($ground_info[2])//Get the format of the background image
 {
 case 1:$ground_im = imagecreatefromgif ($groundImage);break;
 case 2:$ground_im = imagecreatefromjpeg($groundImage);break;
 case 3:$ground_im = imagecreatefrompng($groundImage);break;
 default:die($formatMsg);
 }
 }
 else
 {
 die("The picture that needs to be watermarked does not exist!");
 }
 //Watermark position
 if($isWaterImage)//Picture watermark
 {
 $w = $water_w;
 $h = $ water_h;
 $label = "Picture";
 }
 else//Text watermark
 {
 $temp = imagettfbbox(ceil($textFont*5),0,"./cour.ttf",$waterText);/ /Get the range of text using TrueType font
 $w = $temp[2] - $temp[6];
 $h = $temp[3] - $temp[7];
 unset($temp);
 $ label = "text area";
 }
 if( ($ground_w<$w) || ($ground_h<$h) )
 {
 echo "The length or width of the image that needs to be watermarked is greater than the watermark".$label. "It's too young to generate a watermark! ";
 return;
 }
 switch($waterPos)
 {
 case 0://random
 $posX = rand(0,($ground_w - $w));
 $posY = rand(0,($ground_h - $h));
 break;
 case 1://1 is top left
 $posX = 0;
 $posY = 0;
 break;
 case 2://2 is top center
 $posX = ($ ground_w - $w) / 2;
 $posY = 0;
 break;
 case 3://3 is top right
 $posX = $ground_w - $w;
 $posY = 0;
 break;
 case 4 ://4 means center left
 $posX = 0;
 $posY = ($ground_h - $h) / 2;
 break;
 case 5://5 means center center
 $posX = ($ground_w - $w ) / 2;
 $posY = ($ground_h - $h) / 2;
 break;
 case 6://6 is the center right
 $posX = $ground_w - $w;
 $posY = ($ground_h - $h) / 2;
 break;
 case 7://7 means the bottom is on the left
 $posX = 0;
 $posY = $ground_h - $h;
 break;
 case 8://8 means the bottom is in the center
 $posX = ($ground_w - $w) / 2;
 $posY = $ground_h - $h;
 break;
 case 9://9 is bottom right
 $posX = $ground_w - $w;
 $posY = $ground_h - $h;
 break;
 default://random
 $posX = rand(0,($ground_w - $w));
 $posY = rand(0,($ground_h - $h) );
 break;
 }
 //Set the color mixing mode of the image
 imagealphablending($ground_im, true);
 if($isWaterImage)//Image watermark
 {
 imagecopy($ground_im, $water_im, $posX, $ posY, 0, 0, $water_w,$water_h);//Copy the watermark to the target file
 }
 else//Text watermark
 {
 if( !empty($textColor) && (strlen($textColor)==7) )
 {
 $R = hexdec(substr($textColor,1,2));
 $G = hexdec(substr($textColor,3,2));
 $B = hexdec(substr($textColor,5) );
 }
 else
 {
 die("The watermark text color format is incorrect! ");
 }
 imagestring ( $ground_im, $textFont, $posX, $posY, $waterText, imagecolorallocate($ground_im, $R, $G, $B));
 }
 //The image after generating the watermark
 @unlink($groundImage);
 switch($ground_info[2])//Get the format of the background image
 {
 case 1:imagegif($ground_im,$groundImage);break;
 case 2:imagejpeg($ground_im,$ groundImage);break;
 case 3:imagepng($ground_im,$groundImage);break;
 default:die($errorMsg);
 }

 //Release memory
 if(isset($water_info)) unset($water_info );
 if(isset($water_im)) imagedestroy($water_im);
 unset($ground_info);
 imagedestroy($ground_im);
}
$uploadfile="your_picture.jpg"; //Background image to be processed Position
$waterImage="Hat.png"; //Transparent image position
imageWaterMark($uploadfile,9,$waterImage);
//Displayed on the web
echo "";
?>