PHP中怎么实现生成图片水印

$font_path = "GILSANUB.TTF"; // Font file  $font_size = 30; // in pixcels  $water_mark_text_2 = "phpfuns"; // Watermark Text  function watermark_text($oldimage_name, $new_image_name)  {  global $font_path, $font_size, $water_mark_text_2;  list($owidth,$oheight) = getimagesize($oldimage_name);  $width = $height = 300;  $image = imagecreatetruecolor($width, $height);  $image_src = imagecreatefromjpeg($oldimage_name);  imagecopyresampled($image, $image_src, 0, 0, 0, 0, $width, $height, $owidth, $oheight);  $blue = imagecolorallocate($image, 79, 166, 185);  imagettftext($image, $font_size, 0, 68, 190, $blue, $font_path, $water_mark_text_2);  imagejpeg($image, $new_image_name, 100);  imagedestroy($image);  unlink($oldimage_name);  return true;  }

$image_path = "phpfuns.png";  function watermark_image($oldimage_name, $new_image_name)  /{  global $image_path;  list($owidth,$oheight) = getimagesize($oldimage_name);  $width = $height = 300;  $im = imagecreatetruecolor($width, $height);  $img_src = imagecreatefromjpeg($oldimage_name);  imagecopyresampled($im, $img_src, 0, 0, 0, 0, $width, $height, $owidth, $oheight);  $watermark = imagecreatefrompng($image_path);  list($w_width, $w_height) = getimagesize($image_path);  $pos_x = $width - $w_width;  $pos_y = $height - $w_height;  imagecopy($im, $watermark, $pos_x, $pos_y, 0, 0, $w_width, $w_height);  imagejpeg($im, $new_image_name, 100);  imagedestroy($im);  unlink($oldimage_name);  return true;  }

<?php  $demo_image= "";  if(isset($_POST['createmark']) and $_POST['createmark'] == "Submit")  {  $path = "uploads/";  $valid_formats = array("jpg", "bmp","jpeg");  $name = $_FILES['imgfile']['name'];  if(strlen($name))  {  list($txt, $ext) = explode(".", $name);  if(in_array($ext,$valid_formats) && $_FILES['imgfile']['size'] <= 256*1024)  {  $upload_status = move_uploaded_file($_FILES['imgfile']['tmp_name'], $path.$_FILES['imgfile']['name']);  if($upload_status){  $new_name = $path.time().".jpg";  // Here you have to user functins watermark_text or watermark_image  if(watermark_text($path.$_FILES['imgfile']['name'], $new_name))  $demo_image = $new_name;  }  }  else $msg="File size Max 256 KB or Invalid file format.";  }  }  ?>  // HTML Code  <form name="imageUpload" method="post" enctype="multipart/form-data" >  Upload Image  Image :<input type="file" name="imgfile" /><br />  <input type="submit" name="createmark" value="Submit" />  <?php  if(!emptyempty($demo_image))  echo '<img src="'.$demo_image.'" />';  ?>  </form>