<?php
session_start();
if($_POST[amount]) {
list($width, $height) = GetImageSize($_SESSION['filename']);
$extension = $_SESSION['extension'];
$function_to_read = "ImageCreateFrom".$extension;
$function_to_write = "Image".$extension;
$size = GetImageSize($_SESSION['filename']);
// Read the source file
// Read the source file
$source_handle = $function_to_read ($_SESSION['filename']);
//create a blank image
$destination_handle = ImageCreateTrueColor( $width, $height );
//resize it
ImageCopyResampled( $destination_handle, $source_handle, 0, 0, 0, 0, $width, $height, $size[0], $size[1] );
$amount = $_POST[amount];
$radius = $_POST[radius];
$threshold = $_POST[threshold];
$img = $destination_handle;
function UnsharpMask($img, $amount, $radius, $threshold) {
////////////////////////////////////////////////////////////////////////////////////////////////
////
//// p h p U n s h a r p M a s k
////
//// Unsharp mask algorithm by Torstein Hønsi 2003.
//// thoensi_at_netcom_dot_no.
//// Please leave this notice.
////
///////////////////////////////////////////////////////////////////////////////////////////////
// $img is an image that is already created within php using
// imgcreatetruecolor. No url! $img must be a truecolor image.
// Attempt to calibrate the parameters to Photoshop:
if ($amount > 500) $amount = 500;
$amount = $amount * 0.016;
if ($radius > 50) $radius = 50;
$radius = $radius * 2;
if ($threshold > 255) $threshold = 255;
$radius = abs(round($radius)); // Only integers make sense.
if ($radius == 0) {
return $img; imagedestroy($img); break; }
$w = imagesx($img); $h = imagesy($img);
$imgCanvas = imagecreatetruecolor($w, $h);
$imgCanvas2 = imagecreatetruecolor($w, $h);
$imgBlur = imagecreatetruecolor($w, $h);
$imgBlur2 = imagecreatetruecolor($w, $h);
imagecopy ($imgCanvas, $img, 0, 0, 0, 0, $w, $h);
imagecopy ($imgCanvas2, $img, 0, 0, 0, 0, $w, $h);
// Gaussian blur matrix:
//
// 1 2 1
// 2 4 2
// 1 2 1
//
//////////////////////////////////////////////////
// Move copies of the image around one pixel at the time and merge them with weight
// according to the matrix. The same matrix is simply repeated for higher radii.
for ($i = 0; $i < $radius; $i++) {
imagecopy ($imgBlur, $imgCanvas, 0, 0, 1, 1, $w - 1, $h - 1); // up left
imagecopymerge ($imgBlur, $imgCanvas, 1, 1, 0, 0, $w, $h, 50); // down right
imagecopymerge ($imgBlur, $imgCanvas, 0, 1, 1, 0, $w - 1, $h, 33.33333); // down left
imagecopymerge ($imgBlur, $imgCanvas, 1, 0, 0, 1, $w, $h - 1, 25); // up right
imagecopymerge ($imgBlur, $imgCanvas, 0, 0, 1, 0, $w - 1, $h, 33.33333); // left
imagecopymerge ($imgBlur, $imgCanvas, 1, 0, 0, 0, $w, $h, 25); // right
imagecopymerge ($imgBlur, $imgCanvas, 0, 0, 0, 1, $w, $h - 1, 20 ); // up
imagecopymerge ($imgBlur, $imgCanvas, 0, 1, 0, 0, $w, $h, 16.666667); // down
imagecopymerge ($imgBlur, $imgCanvas, 0, 0, 0, 0, $w, $h, 50); // center
imagecopy ($imgCanvas, $imgBlur, 0, 0, 0, 0, $w, $h);
// During the loop above the blurred copy darkens, possibly due to a roundoff
// error. Therefore the sharp picture has to go through the same loop to
// produce a similar image for comparison. This is not a good thing, as processing
// time increases heavily.
imagecopy ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h);
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 50);
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 33.33333);
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 25);
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 33.33333);
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 25);
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 20 );
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 16.666667);
imagecopymerge ($imgBlur2, $imgCanvas2, 0, 0, 0, 0, $w, $h, 50);
imagecopy ($imgCanvas2, $imgBlur2, 0, 0, 0, 0, $w, $h);
}
// Calculate the difference between the blurred pixels and the original
// and set the pixels
for ($x = 0; $x < $w; $x++) { // each row
for ($y = 0; $y < $h; $y++) { // each pixel
$rgbOrig = ImageColorAt($imgCanvas2, $x, $y);
$rOrig = (($rgbOrig >> 16) & 0xFF);
$gOrig = (($rgbOrig >> 8) & 0xFF);
$bOrig = ($rgbOrig & 0xFF);
$rgbBlur = ImageColorAt($imgCanvas, $x, $y);
$rBlur = (($rgbBlur >> 16) & 0xFF);
$gBlur = (($rgbBlur >> 8) & 0xFF);
$bBlur = ($rgbBlur & 0xFF);
// When the masked pixels differ less from the original
// than the threshold specifies, they are set to their original value.
$rNew = (abs($rOrig - $rBlur) >= $threshold)
? max(0, min(255, ($amount * ($rOrig - $rBlur)) + $rOrig))
: $rOrig;
$gNew = (abs($gOrig - $gBlur) >= $threshold)
? max(0, min(255, ($amount * ($gOrig - $gBlur)) + $gOrig))
: $gOrig;
$bNew = (abs($bOrig - $bBlur) >= $threshold)
? max(0, min(255, ($amount * ($bOrig - $bBlur)) + $bOrig))
: $bOrig;
if (($rOrig != $rNew) || ($gOrig != $gNew) || ($bOrig != $bNew)) {
$pixCol = ImageColorAllocate($img, $rNew, $gNew, $bNew);
ImageSetPixel($img, $x, $y, $pixCol);
}
}
}
imagedestroy($imgCanvas);
imagedestroy($imgCanvas2);
imagedestroy($imgBlur);
imagedestroy($imgBlur2);
return $img;
}
//save the undo image
@copy($_SESSION['filename'],$_SESSION['undo']);
//call unsharp mask function
UnsharpMask($img, $amount, $radius, $threshold);
$function_to_write( $img, $_SESSION['filename'], 100 );
ImageDestroy($img);
echo "<script>
opener.document.location.reload();
self.close();
</script>";
}
else {
//show input form
?>
<p>
<form action="sharpen.php" method="post" name="blur">
Sharpen using the Unsharp Mask technique<br><br />
The Amount parameter simply says how much of the effect you want. 100 is 'normal'.
Radius is the radius of the blurring circle of the mask. 'Threshold' is the least
difference in colour values that is allowed between the original and the mask. In practice
this means that low-contrast areas of the picture are left unrendered whereas edges
are treated normally. This is good for pictures of e.g. skin or blue skies.<br /><br />
Amount (typically 50 - 200): <input name="amount" type="text" size="3" maxlength="3" /><br />
Radius (typically 0.5 - 1): <input name="radius" type="text" size="3" maxlength="3" /><br />
Threshold (typically 0 - 5): <input name="threshold" type="text" size="3" maxlength="3" />
<br /><br />
<input name="submit" type="submit" value="Sharpen"></form>
</p>
<?php
}
?>