_php tutorial on implementing image Sharpening in PHP

　　

Types of Read images

1 = GIF, 2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF (Intel byte order), 8 = TIFF (Motorola byte order), 9 = JPC , ten = JP2, one = JPX, one = JB2, and the SWC, = IFF

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

Image Sharpening

$SCR _im: Image resource handle, $degree: Sharpening degrees

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
";

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 ("The specified file does not exist or is not a valid picture or unsupported type!") ");

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

if ($ImageType >3) die ("Unsupported picture Type! ");

$im 1 = $ImageFunctions [$ImageType] ($_post["ImageName"]);

$im 2 = $ImageFunctions [$ImageType] ($_post["ImageName"]);

Print_r (Imagecolorsforindex ($im, Imagecolorat ($im, 10, 10));

Sharp ($im 1, $im 2, $_post["degree"]);

Header ("Content-type:image/png");

Imagepng ($im 2);

Imagedestroy ($im 1);

Imagedestroy ($im 2);

}

?>

　　　

Changed a bit, save a $im:

Function Sharp2 (& $im, $degree)

{

$cnt = 0;

For ($x =imagesx ($im)-1; $x >0; $x-)

For ($y =imagesy ($im)-1; $y >0; $y-)

{

$CLR 1 = imagecolorsforindex ($im, Imagecolorat ($im, $x-1, $y-1));

$CLR 2 = Imagecolorsforindex ($im, Imagecolorat ($im, $x, $y));

$r = intval ($clr 2["Red"]+ $degree * ($clr 2["Red"-$clr 1["Red"]));

$g = intval ($clr 2["green"]+ $degree * ($clr 2["green"]-$clr 1["green"));

$b = intval ($clr 2["Blue"]+ $degree * ($clr 2["Blue"-$clr 1["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
";

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);

}

}

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