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413 lines
13 KiB
413 lines
13 KiB
/*
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Ported to JavaScript by Lazar Laszlo 2011
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lazarsoft@gmail.com, www.lazarsoft.info
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*/
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/*
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*
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* Copyright 2007 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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function PerspectiveTransform( a11, a21, a31, a12, a22, a32, a13, a23, a33)
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{
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this.a11 = a11;
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this.a12 = a12;
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this.a13 = a13;
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this.a21 = a21;
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this.a22 = a22;
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this.a23 = a23;
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this.a31 = a31;
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this.a32 = a32;
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this.a33 = a33;
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this.transformPoints1=function( points)
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{
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var max = points.length;
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var a11 = this.a11;
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var a12 = this.a12;
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var a13 = this.a13;
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var a21 = this.a21;
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var a22 = this.a22;
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var a23 = this.a23;
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var a31 = this.a31;
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var a32 = this.a32;
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var a33 = this.a33;
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for (var i = 0; i < max; i += 2)
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{
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var x = points[i];
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var y = points[i + 1];
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var denominator = a13 * x + a23 * y + a33;
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points[i] = (a11 * x + a21 * y + a31) / denominator;
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points[i + 1] = (a12 * x + a22 * y + a32) / denominator;
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}
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}
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this. transformPoints2=function(xValues, yValues)
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{
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var n = xValues.length;
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for (var i = 0; i < n; i++)
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{
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var x = xValues[i];
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var y = yValues[i];
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var denominator = this.a13 * x + this.a23 * y + this.a33;
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xValues[i] = (this.a11 * x + this.a21 * y + this.a31) / denominator;
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yValues[i] = (this.a12 * x + this.a22 * y + this.a32) / denominator;
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}
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}
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this.buildAdjoint=function()
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{
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// Adjoint is the transpose of the cofactor matrix:
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return new PerspectiveTransform(this.a22 * this.a33 - this.a23 * this.a32, this.a23 * this.a31 - this.a21 * this.a33, this.a21 * this.a32 - this.a22 * this.a31, this.a13 * this.a32 - this.a12 * this.a33, this.a11 * this.a33 - this.a13 * this.a31, this.a12 * this.a31 - this.a11 * this.a32, this.a12 * this.a23 - this.a13 * this.a22, this.a13 * this.a21 - this.a11 * this.a23, this.a11 * this.a22 - this.a12 * this.a21);
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}
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this.times=function( other)
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{
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return new PerspectiveTransform(this.a11 * other.a11 + this.a21 * other.a12 + this.a31 * other.a13, this.a11 * other.a21 + this.a21 * other.a22 + this.a31 * other.a23, this.a11 * other.a31 + this.a21 * other.a32 + this.a31 * other.a33, this.a12 * other.a11 + this.a22 * other.a12 + this.a32 * other.a13, this.a12 * other.a21 + this.a22 * other.a22 + this.a32 * other.a23, this.a12 * other.a31 + this.a22 * other.a32 + this.a32 * other.a33, this.a13 * other.a11 + this.a23 * other.a12 +this.a33 * other.a13, this.a13 * other.a21 + this.a23 * other.a22 + this.a33 * other.a23, this.a13 * other.a31 + this.a23 * other.a32 + this.a33 * other.a33);
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}
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}
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PerspectiveTransform.quadrilateralToQuadrilateral=function( x0, y0, x1, y1, x2, y2, x3, y3, x0p, y0p, x1p, y1p, x2p, y2p, x3p, y3p)
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{
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var qToS = this.quadrilateralToSquare(x0, y0, x1, y1, x2, y2, x3, y3);
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var sToQ = this.squareToQuadrilateral(x0p, y0p, x1p, y1p, x2p, y2p, x3p, y3p);
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return sToQ.times(qToS);
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}
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PerspectiveTransform.squareToQuadrilateral=function( x0, y0, x1, y1, x2, y2, x3, y3)
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{
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var dy2 = y3 - y2;
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var dy3 = y0 - y1 + y2 - y3;
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if (dy2 == 0.0 && dy3 == 0.0)
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{
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return new PerspectiveTransform(x1 - x0, x2 - x1, x0, y1 - y0, y2 - y1, y0, 0.0, 0.0, 1.0);
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}
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else
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{
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var dx1 = x1 - x2;
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var dx2 = x3 - x2;
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var dx3 = x0 - x1 + x2 - x3;
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var dy1 = y1 - y2;
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var denominator = dx1 * dy2 - dx2 * dy1;
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var a13 = (dx3 * dy2 - dx2 * dy3) / denominator;
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var a23 = (dx1 * dy3 - dx3 * dy1) / denominator;
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return new PerspectiveTransform(x1 - x0 + a13 * x1, x3 - x0 + a23 * x3, x0, y1 - y0 + a13 * y1, y3 - y0 + a23 * y3, y0, a13, a23, 1.0);
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}
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}
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PerspectiveTransform.quadrilateralToSquare=function( x0, y0, x1, y1, x2, y2, x3, y3)
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{
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// Here, the adjoint serves as the inverse:
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return this.squareToQuadrilateral(x0, y0, x1, y1, x2, y2, x3, y3).buildAdjoint();
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}
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function DetectorResult(bits, points)
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{
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this.bits = bits;
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this.points = points;
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}
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function Detector(image)
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{
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this.image=image;
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this.resultPointCallback = null;
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this.sizeOfBlackWhiteBlackRun=function( fromX, fromY, toX, toY)
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{
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// Mild variant of Bresenham's algorithm;
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// see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
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var steep = Math.abs(toY - fromY) > Math.abs(toX - fromX);
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if (steep)
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{
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var temp = fromX;
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fromX = fromY;
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fromY = temp;
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temp = toX;
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toX = toY;
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toY = temp;
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}
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var dx = Math.abs(toX - fromX);
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var dy = Math.abs(toY - fromY);
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var error = - dx >> 1;
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var ystep = fromY < toY?1:- 1;
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var xstep = fromX < toX?1:- 1;
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var state = 0; // In black pixels, looking for white, first or second time
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for (var x = fromX, y = fromY; x != toX; x += xstep)
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{
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var realX = steep?y:x;
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var realY = steep?x:y;
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if (state == 1)
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{
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// In white pixels, looking for black
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if (this.image[realX + realY*qrcode.width])
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{
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state++;
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}
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}
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else
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{
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if (!this.image[realX + realY*qrcode.width])
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{
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state++;
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}
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}
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if (state == 3)
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{
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// Found black, white, black, and stumbled back onto white; done
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var diffX = x - fromX;
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var diffY = y - fromY;
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return Math.sqrt( (diffX * diffX + diffY * diffY));
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}
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error += dy;
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if (error > 0)
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{
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if (y == toY)
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{
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break;
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}
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y += ystep;
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error -= dx;
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}
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}
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var diffX2 = toX - fromX;
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var diffY2 = toY - fromY;
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return Math.sqrt( (diffX2 * diffX2 + diffY2 * diffY2));
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}
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this.sizeOfBlackWhiteBlackRunBothWays=function( fromX, fromY, toX, toY)
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{
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var result = this.sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY);
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// Now count other way -- don't run off image though of course
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var scale = 1.0;
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var otherToX = fromX - (toX - fromX);
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if (otherToX < 0)
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{
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scale = fromX / (fromX - otherToX);
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otherToX = 0;
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}
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else if (otherToX >= qrcode.width)
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{
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scale = (qrcode.width - 1 - fromX) / (otherToX - fromX);
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otherToX = qrcode.width - 1;
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}
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var otherToY = Math.floor (fromY - (toY - fromY) * scale);
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scale = 1.0;
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if (otherToY < 0)
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{
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scale = fromY / (fromY - otherToY);
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otherToY = 0;
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}
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else if (otherToY >= qrcode.height)
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{
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scale = (qrcode.height - 1 - fromY) / (otherToY - fromY);
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otherToY = qrcode.height - 1;
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}
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otherToX = Math.floor (fromX + (otherToX - fromX) * scale);
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result += this.sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY);
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return result - 1.0; // -1 because we counted the middle pixel twice
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}
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this.calculateModuleSizeOneWay=function( pattern, otherPattern)
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{
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var moduleSizeEst1 = this.sizeOfBlackWhiteBlackRunBothWays(Math.floor( pattern.X), Math.floor( pattern.Y), Math.floor( otherPattern.X), Math.floor(otherPattern.Y));
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var moduleSizeEst2 = this.sizeOfBlackWhiteBlackRunBothWays(Math.floor(otherPattern.X), Math.floor(otherPattern.Y), Math.floor( pattern.X), Math.floor(pattern.Y));
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if (isNaN(moduleSizeEst1))
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{
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return moduleSizeEst2 / 7.0;
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}
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if (isNaN(moduleSizeEst2))
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{
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return moduleSizeEst1 / 7.0;
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}
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// Average them, and divide by 7 since we've counted the width of 3 black modules,
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// and 1 white and 1 black module on either side. Ergo, divide sum by 14.
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return (moduleSizeEst1 + moduleSizeEst2) / 14.0;
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}
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this.calculateModuleSize=function( topLeft, topRight, bottomLeft)
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{
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// Take the average
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return (this.calculateModuleSizeOneWay(topLeft, topRight) + this.calculateModuleSizeOneWay(topLeft, bottomLeft)) / 2.0;
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}
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this.distance=function( pattern1, pattern2)
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{
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var xDiff = pattern1.X - pattern2.X;
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var yDiff = pattern1.Y - pattern2.Y;
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return Math.sqrt( (xDiff * xDiff + yDiff * yDiff));
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}
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this.computeDimension=function( topLeft, topRight, bottomLeft, moduleSize)
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{
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var tltrCentersDimension = Math.round(this.distance(topLeft, topRight) / moduleSize);
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var tlblCentersDimension = Math.round(this.distance(topLeft, bottomLeft) / moduleSize);
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var dimension = ((tltrCentersDimension + tlblCentersDimension) >> 1) + 7;
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switch (dimension & 0x03)
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{
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// mod 4
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case 0:
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dimension++;
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break;
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// 1? do nothing
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case 2:
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dimension--;
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break;
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case 3:
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throw "Error";
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}
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return dimension;
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}
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this.findAlignmentInRegion=function( overallEstModuleSize, estAlignmentX, estAlignmentY, allowanceFactor)
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{
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// Look for an alignment pattern (3 modules in size) around where it
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// should be
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var allowance = Math.floor (allowanceFactor * overallEstModuleSize);
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var alignmentAreaLeftX = Math.max(0, estAlignmentX - allowance);
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var alignmentAreaRightX = Math.min(qrcode.width - 1, estAlignmentX + allowance);
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if (alignmentAreaRightX - alignmentAreaLeftX < overallEstModuleSize * 3)
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{
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throw "Error";
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}
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var alignmentAreaTopY = Math.max(0, estAlignmentY - allowance);
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var alignmentAreaBottomY = Math.min(qrcode.height - 1, estAlignmentY + allowance);
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var alignmentFinder = new AlignmentPatternFinder(this.image, alignmentAreaLeftX, alignmentAreaTopY, alignmentAreaRightX - alignmentAreaLeftX, alignmentAreaBottomY - alignmentAreaTopY, overallEstModuleSize, this.resultPointCallback);
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return alignmentFinder.find();
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}
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this.createTransform=function( topLeft, topRight, bottomLeft, alignmentPattern, dimension)
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{
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var dimMinusThree = dimension - 3.5;
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var bottomRightX;
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var bottomRightY;
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var sourceBottomRightX;
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var sourceBottomRightY;
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if (alignmentPattern != null)
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{
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bottomRightX = alignmentPattern.X;
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bottomRightY = alignmentPattern.Y;
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sourceBottomRightX = sourceBottomRightY = dimMinusThree - 3.0;
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}
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else
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{
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// Don't have an alignment pattern, just make up the bottom-right point
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bottomRightX = (topRight.X - topLeft.X) + bottomLeft.X;
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bottomRightY = (topRight.Y - topLeft.Y) + bottomLeft.Y;
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sourceBottomRightX = sourceBottomRightY = dimMinusThree;
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}
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var transform = PerspectiveTransform.quadrilateralToQuadrilateral(3.5, 3.5, dimMinusThree, 3.5, sourceBottomRightX, sourceBottomRightY, 3.5, dimMinusThree, topLeft.X, topLeft.Y, topRight.X, topRight.Y, bottomRightX, bottomRightY, bottomLeft.X, bottomLeft.Y);
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return transform;
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}
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this.sampleGrid=function( image, transform, dimension)
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{
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var sampler = GridSampler;
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return sampler.sampleGrid3(image, dimension, transform);
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}
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this.processFinderPatternInfo = function( info)
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{
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var topLeft = info.TopLeft;
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var topRight = info.TopRight;
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var bottomLeft = info.BottomLeft;
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var moduleSize = this.calculateModuleSize(topLeft, topRight, bottomLeft);
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if (moduleSize < 1.0)
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{
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throw "Error";
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}
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var dimension = this.computeDimension(topLeft, topRight, bottomLeft, moduleSize);
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var provisionalVersion = Version.getProvisionalVersionForDimension(dimension);
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var modulesBetweenFPCenters = provisionalVersion.DimensionForVersion - 7;
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var alignmentPattern = null;
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// Anything above version 1 has an alignment pattern
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if (provisionalVersion.AlignmentPatternCenters.length > 0)
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{
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// Guess where a "bottom right" finder pattern would have been
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var bottomRightX = topRight.X - topLeft.X + bottomLeft.X;
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var bottomRightY = topRight.Y - topLeft.Y + bottomLeft.Y;
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// Estimate that alignment pattern is closer by 3 modules
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// from "bottom right" to known top left location
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var correctionToTopLeft = 1.0 - 3.0 / modulesBetweenFPCenters;
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var estAlignmentX = Math.floor (topLeft.X + correctionToTopLeft * (bottomRightX - topLeft.X));
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var estAlignmentY = Math.floor (topLeft.Y + correctionToTopLeft * (bottomRightY - topLeft.Y));
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// Kind of arbitrary -- expand search radius before giving up
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for (var i = 4; i <= 16; i <<= 1)
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{
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//try
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//{
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alignmentPattern = this.findAlignmentInRegion(moduleSize, estAlignmentX, estAlignmentY, i);
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break;
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//}
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//catch (re)
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//{
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// try next round
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//}
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}
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// If we didn't find alignment pattern... well try anyway without it
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}
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var transform = this.createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension);
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var bits = this.sampleGrid(this.image, transform, dimension);
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var points;
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if (alignmentPattern == null)
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{
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points = new Array(bottomLeft, topLeft, topRight);
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}
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else
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{
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points = new Array(bottomLeft, topLeft, topRight, alignmentPattern);
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}
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return new DetectorResult(bits, points);
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}
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this.detect=function()
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{
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var info = new FinderPatternFinder().findFinderPattern(this.image);
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return this.processFinderPatternInfo(info);
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}
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}
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