在PHP中实现图片的锐化

    <?


  //读取图像的类型


  //1 = GIF, 2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF(intel byte order), 8 = TIFF(motorola byte order), 9 = JPC, 10 = JP2, 11 = JPX, 12 = JB2, 13 = SWC, 14 = IFF


  function GetImageType($filename) {return (($imginfo=@getimagesize($filename))!=null ? $imginfo[2] : null);}   


  //图像锐化


  //$scr_im:图像资源句柄,$degree:锐化度数


  function Sharp(&$src_im, &$dst_im, $degree)


  {


   $src_x = imagesx($src_im);


   $src_y = imagesy($src_im);


   //$dst_im = imagecreate($src_x, $src_y);


   //imagecopy($dst_im, $src_im, 0, 0, 0, 0, $src_x, $src_y);


   $cnt = 0;


   for ($x=1; $x<$src_x; $x++)


   for ($y=1; $y<$src_y; $y++)


   {


   $src_clr1 = imagecolorsforindex($src_im, imagecolorat($src_im, $x-1, $y-1));


   $src_clr2 = imagecolorsforindex($src_im, imagecolorat($src_im, $x, $y));


   $r = intval($src_clr2[“red”]+$degree*($src_clr2[“red”]-$src_clr1[“red”]));


   $g = intval($src_clr2[“green”]+$degree*($src_clr2[“green”]-$src_clr1[“green”]));


   $b = intval($src_clr2[“blue”]+$degree*($src_clr2[“blue”]-$src_clr1[“blue”]));


   $r = min(255, max($r, 0));


   $g = min(255, max($g, 0));


   $b = min(255, max($b, 0));


   //echo “r:$r, g:$g, b:$b<br/>”;


   if (($dst_clr=imagecolorexact($dst_im, $r, $g, $b))==-1)


   $dst_clr = Imagecolorallocate($dst_im, $r, $g, $b);


   $cnt++;


   if ($dst_clr==-1) die(“color allocate faile at $x, $y ($cnt).”);


   imagesetpixel($dst_im, $x, $y, $dst_clr);


   }


   return $dst_im;


  }   


  $ImageFunctions = array(“imagecreatefromwbmp”, “imagecreatefromgif”, “imagecreatefromjpeg”, “imagecreatefrompng”);   


    if (!empty($_POST[“ImageName”]))


  { 


   set_time_limit(10*60);


   if (($ImageType=GetImageType($_POST[“ImageName”]))==false)


   die(“指定文件不存在或不是有效的图片或不支持类型!”);


   if ($ImageType==6) $ImageType = 0;


   if ($ImageType>3) die(“不支持的图片类型!”);


   $im1 = $ImageFunctions[$ImageType]($_POST[“ImageName”]);


   $im2 = $ImageFunctions[$ImageType]($_POST[“ImageName”]);


   //print_r(imagecolorsforindex($im, imagecolorat($im, 10, 10)));


   Sharp($im1, $im2, $_POST[“Degree”]);


   header(“Content-type: image/png”);


   imagepng($im2);


   imagedestroy($im1);


   imagedestroy($im2);


  } 


  ?>


  <form name=”FormName” action=”” method=”post”>


  请输入图片的本地路径或URL:<br/>


  <input name=”ImageName” type=”text” value=”<?=$_POST[“ImageName”]?>” size=32><br/>


  锐化度数(例:0.6、3.0):<br/>


  <input name=”Degree” type=”text” value=”<?=$_POST[“Degree”]?>”><br/>


  <input type=”submit” value=”提交”>


  </form> 


   改了一下,省了一个$im:  


   function Sharp2(&$im, $degree)


  {


   $cnt = 0;


   for ($x=imagesx($im)-1; $x>0; $x–)


   for ($y=imagesy($im)-1; $y>0; $y–)

#p#副标题#e#


   {


   $clr1 = imagecolorsforindex($im, imagecolorat($im, $x-1, $y-1));


   $clr2 = imagecolorsforindex($im, imagecolorat($im, $x, $y));


   $r = intval($clr2[“red”]+$degree*($clr2[“red”]-$clr1[“red”]));


   $g = intval($clr2[“green”]+$degree*($clr2[“green”]-$clr1[“green”]));


   $b = intval($clr2[“blue”]+$degree*($clr2[“blue”]-$clr1[“blue”]));


   $r = min(255, max($r, 0));


   $g = min(255, max($g, 0));


   $b = min(255, max($b, 0));


   //echo “r:$r, g:$g, b:$b<br>”;


   if (($new_clr=imagecolorexact($im, $r, $g, $b))==-1)


   $new_clr = Imagecolorallocate($im, $r, $g, $b);


   $cnt++;


   if ($new_clr==-1) die(“color allocate faile at $x, $y ($cnt).”);


   imagesetpixel($im, $x, $y, $new_clr);


   }


  }