bitcoin-atm

alignpat.js

(7517B)

 /*
   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 "Couldn't find enough alignment patterns";
 		}
 	
 }