grid.js

/*
  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.
*/


GridSampler = {};

GridSampler.checkAndNudgePoints=function( image,  points)
		{
			var width = qrcode.width;
			var height = qrcode.height;
			// Check and nudge points from start until we see some that are OK:
			var nudged = true;
			for (var offset = 0; offset < points.Length && nudged; offset += 2)
			{
				var x = Math.floor (points[offset]);
				var y = Math.floor( points[offset + 1]);
				if (x < - 1 || x > width || y < - 1 || y > height)
				{
					throw "Error.checkAndNudgePoints ";
				}
				nudged = false;
				if (x == - 1)
				{
					points[offset] = 0.0;
					nudged = true;
				}
				else if (x == width)
				{
					points[offset] = width - 1;
					nudged = true;
				}
				if (y == - 1)
				{
					points[offset + 1] = 0.0;
					nudged = true;
				}
				else if (y == height)
				{
					points[offset + 1] = height - 1;
					nudged = true;
				}
			}
			// Check and nudge points from end:
			nudged = true;
			for (var offset = points.Length - 2; offset >= 0 && nudged; offset -= 2)
			{
				var x = Math.floor( points[offset]);
				var y = Math.floor( points[offset + 1]);
				if (x < - 1 || x > width || y < - 1 || y > height)
				{
					throw "Error.checkAndNudgePoints ";
				}
				nudged = false;
				if (x == - 1)
				{
					points[offset] = 0.0;
					nudged = true;
				}
				else if (x == width)
				{
					points[offset] = width - 1;
					nudged = true;
				}
				if (y == - 1)
				{
					points[offset + 1] = 0.0;
					nudged = true;
				}
				else if (y == height)
				{
					points[offset + 1] = height - 1;
					nudged = true;
				}
			}
		}
	


GridSampler.sampleGrid3=function( image,  dimension,  transform)
		{
			var bits = new BitMatrix(dimension);
			var points = new Array(dimension << 1);
			for (var y = 0; y < dimension; y++)
			{
				var max = points.length;
				var iValue =  y + 0.5;
				for (var x = 0; x < max; x += 2)
				{
					points[x] =  (x >> 1) + 0.5;
					points[x + 1] = iValue;
				}
				transform.transformPoints1(points);
				// Quick check to see if points transformed to something inside the image;
				// sufficient to check the endpoints
				GridSampler.checkAndNudgePoints(image, points);
				try
				{
					for (var x = 0; x < max; x += 2)
					{
						var xpoint = (Math.floor( points[x]) * 4) + (Math.floor( points[x + 1]) * qrcode.width * 4);
                        var bit = image[Math.floor( points[x])+ qrcode.width* Math.floor( points[x + 1])];
						qrcode.imagedata.data[xpoint] = bit?255:0;
						qrcode.imagedata.data[xpoint+1] = bit?255:0;
						qrcode.imagedata.data[xpoint+2] = 0;
						qrcode.imagedata.data[xpoint+3] = 255;
						//bits[x >> 1][ y]=bit;
						if(bit)
							bits.set_Renamed(x >> 1, y);
					}
				}
				catch ( aioobe)
				{
					// This feels wrong, but, sometimes if the finder patterns are misidentified, the resulting
					// transform gets "twisted" such that it maps a straight line of points to a set of points
					// whose endpoints are in bounds, but others are not. There is probably some mathematical
					// way to detect this about the transformation that I don't know yet.
					// This results in an ugly runtime exception despite our clever checks above -- can't have
					// that. We could check each point's coordinates but that feels duplicative. We settle for
					// catching and wrapping ArrayIndexOutOfBoundsException.
					throw "Error.checkAndNudgePoints";
				}
			}
			return bits;
		}

GridSampler.sampleGridx=function( image,  dimension,  p1ToX,  p1ToY,  p2ToX,  p2ToY,  p3ToX,  p3ToY,  p4ToX,  p4ToY,  p1FromX,  p1FromY,  p2FromX,  p2FromY,  p3FromX,  p3FromY,  p4FromX,  p4FromY)
{
	var transform = PerspectiveTransform.quadrilateralToQuadrilateral(p1ToX, p1ToY, p2ToX, p2ToY, p3ToX, p3ToY, p4ToX, p4ToY, p1FromX, p1FromY, p2FromX, p2FromY, p3FromX, p3FromY, p4FromX, p4FromY);
			
	return GridSampler.sampleGrid3(image, dimension, transform);
}