136 lines
4.1 KiB
PHP
136 lines
4.1 KiB
PHP
<?php
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/**
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* @author Gasper Kozak
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* @copyright 2007-2011
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This file is part of WideImage.
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WideImage is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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WideImage is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with WideImage; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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* @package Internal/Operations
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**/
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/**
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* Unsharp filter
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*
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* This filter was taken from http://vikjavev.no/computing/ump.php,
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* the original author Torstein Hønsi. Adapted to fit better within
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* the Wideimage package.
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*
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* @package Internal/Operations
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*/
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class WideImage_Operation_Unsharp {
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/**
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* Returns sharpened image
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*
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* @param WideImage_Image $image
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* @param float $amount
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* @param int $radius
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* @param float $threshold
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* @return WideImage_Image
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*/
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function execute($image, $amount, $radius, $threshold) {
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// Attempt to calibrate the parameters to Photoshop:
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if ($amount > 500) $amount = 500;
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$amount = $amount * 0.016;
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if ($radius > 50) $radius = 50;
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$radius = $radius * 2;
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if ($threshold > 255) $threshold = 255;
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$radius = abs(round($radius)); // Only integers make sense.
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if ($radius == 0) {
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return $image;
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}
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// Gaussian blur matrix
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$matrix = array(
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array(1, 2, 1),
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array(2, 4, 2),
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array(1, 2, 1)
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);
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$blurred = $image->applyConvolution($matrix, 16, 0);
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if($threshold > 0) {
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// Calculate the difference between the blurred pixels and the original
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// and set the pixels
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for ($x = 0; $x < $image->getWidth(); $x++) {
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for ($y = 0; $y < $image->getHeight(); $y++) {
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$rgbOrig = $image->getRGBAt($x, $y);
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$rOrig = $rgbOrig["red"];
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$gOrig = $rgbOrig["green"];
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$bOrig = $rgbOrig["blue"];
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$rgbBlur = $blurred->getRGBAt($x, $y);
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$rBlur = $rgbBlur["red"];
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$gBlur = $rgbBlur["green"];
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$bBlur = $rgbBlur["blue"];
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// When the masked pixels differ less from the original
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// than the threshold specifies, they are set to their original value.
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$rNew = (abs($rOrig - $rBlur) >= $threshold)
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? max(0, min(255, ($amount * ($rOrig - $rBlur)) + $rOrig))
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: $rOrig;
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$gNew = (abs($gOrig - $gBlur) >= $threshold)
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? max(0, min(255, ($amount * ($gOrig - $gBlur)) + $gOrig))
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: $gOrig;
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$bNew = (abs($bOrig - $bBlur) >= $threshold)
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? max(0, min(255, ($amount * ($bOrig - $bBlur)) + $bOrig))
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: $bOrig;
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$rgbNew = array("red" => $rNew, "green" => $gNew, "blue" => $bNew, "alpha" => 0);
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if (($rOrig != $rNew) || ($gOrig != $gNew) || ($bOrig != $bNew)) {
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$image->setRGBAt($x, $y, $rgbNew);
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}
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}
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}
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}
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else {
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$w = $image->getWidth();
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$h = $image->getHeight();
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for ($x = 0; $x < $w; $x++) {
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for ($y = 0; $y < $h; $y++) {
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$rgbOrig = $image->getRGBAt($x, $y);
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$rOrig = $rgbOrig["red"];
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$gOrig = $rgbOrig["green"];
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$bOrig = $rgbOrig["blue"];
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$rgbBlur = $blurred->getRGBAt($x, $y);
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$rBlur = $rgbBlur["red"];
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$gBlur = $rgbBlur["green"];
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$bBlur = $rgbBlur["blue"];
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$rNew = ($amount * ($rOrig - $rBlur)) + $rOrig;
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if($rNew>255){$rNew=255;}
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elseif($rNew<0){$rNew=0;}
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$gNew = ($amount * ($gOrig - $gBlur)) + $gOrig;
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if($gNew>255){$gNew=255;}
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elseif($gNew<0){$gNew=0;}
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$bNew = ($amount * ($bOrig - $bBlur)) + $bOrig;
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if($bNew>255){$bNew=255;}
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elseif($bNew<0){$bNew=0;}
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$rgbNew = array("red" => $rNew, "green" => $gNew, "blue" => $bNew, "alpha" => 0);
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$image->setRGBAt($x, $y, $rgbNew);
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}
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}
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}
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return $image;
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}
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}
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