How to implement watermarking on PHP images

The example in this article describes the implementation method of adding watermark to pictures in PHP. Share it with everyone for your reference, the details are as follows:

<&#63;php
echo img_water_mark("2008112023204423477802.gif", "copyImg.png", $savepath=null, $savename="123.gif", $positon=2, $alpha=60);
/**
 * 图片加水印(适用于png/jpg/gif格式)
 * 
 * @author flynetcn
 *
 * @param $srcImg 原图片
 * @param $waterImg 水印图片
 * @param $savepath 保存路径
 * @param $savename 保存名字
 * @param $positon 水印位置 
 * 1:顶部居左, 2:顶部居右, 3:居中, 4:底部局左, 5:底部居右 
 * @param $alpha 透明度 -- 0:完全透明, 100:完全不透明
 * 
 * @return 成功 -- 加水印后的新图片地址
 *     失败 -- -1:原文件不存在, -2:水印图片不存在, -3:原文件图像对象建立失败-4:水印文件图像对象建立失败, -5:加水印后的新图片保存失败
 */
function img_water_mark($srcImg, $waterImg, $savepath=null, $savename=null, $positon=5, $alpha=30)
{
  $temp = pathinfo($srcImg);
  $name = $temp['basename'];
  $path = $temp['dirname'];
  $exte = $temp['extension'];
  $savename = $savename &#63; $savename : $name;
  $savepath = $savepath &#63; $savepath : $path;
  $savefile = $savepath .'/'. $savename;
  $srcinfo = @getimagesize($srcImg);
  if (!$srcinfo) {
    return -1; //原文件不存在
  }
  $waterinfo = @getimagesize($waterImg);
  if (!$waterinfo) {
    return -2; //水印图片不存在
  }
  $srcImgObj = image_create_from_ext($srcImg);
  if (!$srcImgObj) {
    return -3; //原文件图像对象建立失败
  }
  $waterImgObj = image_create_from_ext($waterImg);
  if (!$waterImgObj) {
    return -4; //水印文件图像对象建立失败
  }
  switch ($positon) {
  //1顶部居左
  case 1: $x=$y=0; break;
  //2顶部居右
  case 2: $x = $srcinfo[0]-$waterinfo[0]; $y = 0; break;
  //3居中
  case 3: $x = ($srcinfo[0]-$waterinfo[0])/2; $y = ($srcinfo[1]-$waterinfo[1])/2; break;
  //4底部居左
  case 4: $x = 0; $y = $srcinfo[1]-$waterinfo[1]; break;
  //5底部居右
  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, $savefile); break;
  default: return -5; //保存失败
  }
  imagedestroy($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;
}
&#63;>

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I hope this article will be helpful to everyone in PHP programming.

The above introduces the implementation method of adding watermark to pictures in PHP, including adding watermarks to pictures and p pictures. I hope it will be helpful to friends who are interested in PHP tutorials.