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--)

{

$clr1 = imagecolorsforindex($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);

}

}