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PHP中实现图片的锐化

程序员文章站 2024-02-09 18:27:10
  

  <?

  //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--)

   {

   $clr1 = imagecolorsforindex($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);

   }

  }