<?php
/*
*	Pt (PHP Toolkit)
*	Copyright (C) 2008  Dinu Florin
*
*	Pt is free software: you can redistribute it and/or modify
*	it under the terms of the GNU Lesser General Public License as published by
*	the Free Software Foundation, either version 3 of the License, or
*	any later version.
*
*	Pt is distributed in the hope that it will be useful,
*	but WITHOUT ANY WARRANTY; without even the implied warranty of
*	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*	GNU Lesser General Public License for more details.
*
*	You should have received a copy of the GNU Lesser General Public License
*	along with Pt.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
*	This file contains the ColorReplace filter class.
*	
*	@author		Dinu Florin <contact@florindinu.ro>
*	@package	Modules
*	@subpackage	Images
*/

/**
*	ColorReplace filter class.
*
*	@author		Dinu Florin	<contact@florindinu.ro>
*	@package	Modules
*	@subpackage	Images
*/
class OldColorReplace extends AbstractImageFilter
{
	protected $oldColor = null;
	protected $newColor = null;
	protected $fuzzyness = null;
	
	/**
	*	Constructor.
	*	
	*	@param	mixed	$oldColor	The color to replace.
	*	@param	mixed	$newColor	The new color.
	*	@param	number	$fuzzyness	The fuzzyness of the color replacement.
	*	@note The colors can be either CSS-style ('#FFFFFF') or arrays (array('r', 'g', 'b')).
	*/
	public function __construct($oldColor, $newColor, $fuzzyness = 60)
	{
		$this->oldColor = Image::rgbToHsv((is_string($oldColor) && $oldColor{0} == '#')?Image::decodeColor($oldColor):$oldColor);
		$this->newColor = Image::rgbToHsv((is_string($newColor) && $newColor{0} == '#')?Image::decodeColor($newColor):$newColor);
		
		$this->fuzzyness = $fuzzyness;
	}
	
	/**
	*	Apply to an image
	*
	*	@param	Image	$image	The image to apply the filter to
	*/
	public function applyTo(Image $image)
	{
		$img = $image->getResource();
		
		$satThreshold = 1/(2*$this->fuzzyness);	//Saturation threshold
		$halfFuzzyness = $this->fuzzyness/2;
		
		$imgw = $image->width;
		$imgh = $image->height;
		
		for($y = 0; $y < $imgh; $y++)
		{
			for($x = 0; $x < $imgw; $x++)
			{
				$pixelColor = imagecolorat($img, $x, $y);
				$pixelColor = imagecolorsforindex($img, $pixelColor);
			
				//We need the RGB components to be floats between 0 and 1
				$pixelColor['r'] = $pixelColor['red'];
				$pixelColor['g'] = $pixelColor['green'];
				$pixelColor['b'] = $pixelColor['blue'];
			
				$pixelColor = Image::rgbToHsv($pixelColor);	//Switch to HSV space
				$distance = max($this->oldColor['h'], $pixelColor['h']) - min($this->oldColor['h'], $pixelColor['h']);	//The angle between the colors (hues)
			
				if($distance < $halfFuzzyness && $pixelColor['s'] > $satThreshold)	//Do we need to replace this pixel?
				{
					$pixelColor['h'] = $this->newColor['h'] - $this->oldColor['h'] + $pixelColor['h'];
					$pixelColor['s'] = min(max($this->newColor['s']- $this->oldColor['s'] + $pixelColor['s'] , 0), 1); 
					
					$pixelColor = Image::hsvToRgb($pixelColor);	//Go back to RGB space
					$pixelColor = imagecolorallocate($img, $pixelColor['r'], $pixelColor['g'], $pixelColor['b']);
					imagesetpixel($img, $x, $y, $pixelColor);
				}
			}
		}
		
		$image->setResource($img);
	}
}

?>