text: /*
    Ported to JavaScript by Lazar Laszlo 2011 
    
    lazarsoft@gmail.com, www.lazarsoft.info
    
  */
  
  /*
  *
  * Copyright 2007 ZXing authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
  
  
  function AlignmentPattern(posX, posY,  estimatedModuleSize)
  {
  	this.x=posX;
  	this.y=posY;
  	this.count = 1;
  	this.estimatedModuleSize = estimatedModuleSize;
  	
  	this.__defineGetter__("EstimatedModuleSize", function()
  	{
  		return this.estimatedModuleSize;
  	}); 
  	this.__defineGetter__("Count", function()
  	{
  		return this.count;
  	});
  	this.__defineGetter__("X", function()
  	{
  		return Math.floor(this.x);
  	});
  	this.__defineGetter__("Y", function()
  	{
  		return Math.floor(this.y);
  	});
  	this.incrementCount = function()
  	{
  		this.count++;
  	}
  	this.aboutEquals=function( moduleSize,  i,  j)
  		{
  			if (Math.abs(i - this.y) <= moduleSize && Math.abs(j - this.x) <= moduleSize)
  			{
  				var moduleSizeDiff = Math.abs(moduleSize - this.estimatedModuleSize);
  				return moduleSizeDiff <= 1.0 || moduleSizeDiff / this.estimatedModuleSize <= 1.0;
  			}
  			return false;
  		}
  	
  }
  
  function AlignmentPatternFinder( image,  startX,  startY,  width,  height,  moduleSize,  resultPointCallback)
  {
  	this.image = image;
  	this.possibleCenters = new Array();
  	this.startX = startX;
  	this.startY = startY;
  	this.width = width;
  	this.height = height;
  	this.moduleSize = moduleSize;
  	this.crossCheckStateCount = new Array(0,0,0);
  	this.resultPointCallback = resultPointCallback;
  	
  	this.centerFromEnd=function(stateCount,  end)
  		{
  			return  (end - stateCount[2]) - stateCount[1] / 2.0;
  		}
  	this.foundPatternCross = function(stateCount)
  		{
  			var moduleSize = this.moduleSize;
  			var maxVariance = moduleSize / 2.0;
  			for (var i = 0; i < 3; i++)
  			{
  				if (Math.abs(moduleSize - stateCount[i]) >= maxVariance)
  				{
  					return false;
  				}
  			}
  			return true;
  		}
  
  	this.crossCheckVertical=function( startI,  centerJ,  maxCount,  originalStateCountTotal)
  		{
  			var image = this.image;
  			
  			var maxI = qrcode.height;
  			var stateCount = this.crossCheckStateCount;
  			stateCount[0] = 0;
  			stateCount[1] = 0;
  			stateCount[2] = 0;
  			
  			// Start counting up from center
  			var i = startI;
  			while (i >= 0 && image[centerJ + i*qrcode.width] && stateCount[1] <= maxCount)
  			{
  				stateCount[1]++;
  				i--;
  			}
  			// If already too many modules in this state or ran off the edge:
  			if (i < 0 || stateCount[1] > maxCount)
  			{
  				return NaN;
  			}
  			while (i >= 0 && !image[centerJ + i*qrcode.width] && stateCount[0] <= maxCount)
  			{
  				stateCount[0]++;
  				i--;
  			}
  			if (stateCount[0] > maxCount)
  			{
  				return NaN;
  			}
  			
  			// Now also count down from center
  			i = startI + 1;
  			while (i < maxI && image[centerJ + i*qrcode.width] && stateCount[1] <= maxCount)
  			{
  				stateCount[1]++;
  				i++;
  			}
  			if (i == maxI || stateCount[1] > maxCount)
  			{
  				return NaN;
  			}
  			while (i < maxI && !image[centerJ + i*qrcode.width] && stateCount[2] <= maxCount)
  			{
  				stateCount[2]++;
  				i++;
  			}
  			if (stateCount[2] > maxCount)
  			{
  				return NaN;
  			}
  			
  			var stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2];
  			if (5 * Math.abs(stateCountTotal - originalStateCountTotal) >= 2 * originalStateCountTotal)
  			{
  				return NaN;
  			}
  			
  			return this.foundPatternCross(stateCount)?this.centerFromEnd(stateCount, i):NaN;
  		}
  		
  	this.handlePossibleCenter=function( stateCount,  i,  j)
  		{
  			var stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2];
  			var centerJ = this.centerFromEnd(stateCount, j);
  			var centerI = this.crossCheckVertical(i, Math.floor (centerJ), 2 * stateCount[1], stateCountTotal);
  			if (!isNaN(centerI))
  			{
  				var estimatedModuleSize = (stateCount[0] + stateCount[1] + stateCount[2]) / 3.0;
  				var max = this.possibleCenters.length;
  				for (var index = 0; index < max; index++)
  				{
  					var center =  this.possibleCenters[index];
  					// Look for about the same center and module size:
  					if (center.aboutEquals(estimatedModuleSize, centerI, centerJ))
  					{
  						return new AlignmentPattern(centerJ, centerI, estimatedModuleSize);
  					}
  				}
  				// Hadn't found this before; save it
  				var point = new AlignmentPattern(centerJ, centerI, estimatedModuleSize);
  				this.possibleCenters.push(point);
  				if (this.resultPointCallback != null)
  				{
  					this.resultPointCallback.foundPossibleResultPoint(point);
  				}
  			}
  			return null;
  		}
  		
  	this.find = function()
  	{
  			var startX = this.startX;
  			var height = this.height;
  			var maxJ = startX + width;
  			var middleI = startY + (height >> 1);
  			// We are looking for black/white/black modules in 1:1:1 ratio;
  			// this tracks the number of black/white/black modules seen so far
  			var stateCount = new Array(0,0,0);
  			for (var iGen = 0; iGen < height; iGen++)
  			{
  				// Search from middle outwards
  				var i = middleI + ((iGen & 0x01) == 0?((iGen + 1) >> 1):- ((iGen + 1) >> 1));
  				stateCount[0] = 0;
  				stateCount[1] = 0;
  				stateCount[2] = 0;
  				var j = startX;
  				// Burn off leading white pixels before anything else; if we start in the middle of
  				// a white run, it doesn't make sense to count its length, since we don't know if the
  				// white run continued to the left of the start point
  				while (j < maxJ && !image[j + qrcode.width* i])
  				{
  					j++;
  				}
  				var currentState = 0;
  				while (j < maxJ)
  				{
  					if (image[j + i*qrcode.width])
  					{
  						// Black pixel
  						if (currentState == 1)
  						{
  							// Counting black pixels
  							stateCount[currentState]++;
  						}
  						else
  						{
  							// Counting white pixels
  							if (currentState == 2)
  							{
  								// A winner?
  								if (this.foundPatternCross(stateCount))
  								{
  									// Yes
  									var confirmed = this.handlePossibleCenter(stateCount, i, j);
  									if (confirmed != null)
  									{
  										return confirmed;
  									}
  								}
  								stateCount[0] = stateCount[2];
  								stateCount[1] = 1;
  								stateCount[2] = 0;
  								currentState = 1;
  							}
  							else
  							{
  								stateCount[++currentState]++;
  							}
  						}
  					}
  					else
  					{
  						// White pixel
  						if (currentState == 1)
  						{
  							// Counting black pixels
  							currentState++;
  						}
  						stateCount[currentState]++;
  					}
  					j++;
  				}
  				if (this.foundPatternCross(stateCount))
  				{
  					var confirmed = this.handlePossibleCenter(stateCount, i, maxJ);
  					if (confirmed != null)
  					{
  						return confirmed;
  					}
  				}
  			}
  			
  			// Hmm, nothing we saw was observed and confirmed twice. If we had
  			// any guess at all, return it.
  			if (!(this.possibleCenters.length == 0))
  			{
  				return  this.possibleCenters[0];
  			}
  			
  			throw new Error("Couldn't find enough alignment patterns");
  		}
  	
  }