@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
326 lines (325 loc) • 16.5 kB
JavaScript
"use strict";
/*
* 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.
*/
Object.defineProperty(exports, "__esModule", { value: true });
var MathUtils_1 = require("../../common/detector/MathUtils");
var DetectorResult_1 = require("../../common/DetectorResult");
// import GridSampler from '../../common/GridSampler';
var GridSamplerInstance_1 = require("../../common/GridSamplerInstance");
var PerspectiveTransform_1 = require("../../common/PerspectiveTransform");
var DecodeHintType_1 = require("../../DecodeHintType");
var NotFoundException_1 = require("../../NotFoundException");
var ResultPoint_1 = require("../../ResultPoint");
var Version_1 = require("../decoder/Version");
var AlignmentPatternFinder_1 = require("./AlignmentPatternFinder");
var FinderPatternFinder_1 = require("./FinderPatternFinder");
/*import java.util.Map;*/
/**
* <p>Encapsulates logic that can detect a QR Code in an image, even if the QR Code
* is rotated or skewed, or partially obscured.</p>
*
* @author Sean Owen
*/
var Detector = /** @class */ (function () {
function Detector(image) {
this.image = image;
}
Detector.prototype.getImage = function () {
return this.image;
};
Detector.prototype.getResultPointCallback = function () {
return this.resultPointCallback;
};
/**
* <p>Detects a QR Code in an image.</p>
*
* @return {@link DetectorResult} encapsulating results of detecting a QR Code
* @throws NotFoundException if QR Code cannot be found
* @throws FormatException if a QR Code cannot be decoded
*/
// public detect(): DetectorResult /*throws NotFoundException, FormatException*/ {
// return detect(null)
// }
/**
* <p>Detects a QR Code in an image.</p>
*
* @param hints optional hints to detector
* @return {@link DetectorResult} encapsulating results of detecting a QR Code
* @throws NotFoundException if QR Code cannot be found
* @throws FormatException if a QR Code cannot be decoded
*/
Detector.prototype.detect = function (hints) {
this.resultPointCallback = (hints === null || hints === undefined) ? null :
/*(ResultPointCallback) */ hints.get(DecodeHintType_1.default.NEED_RESULT_POINT_CALLBACK);
var finder = new FinderPatternFinder_1.default(this.image, this.resultPointCallback);
var info = finder.find(hints);
return this.processFinderPatternInfo(info);
};
Detector.prototype.processFinderPatternInfo = function (info) {
var topLeft = info.getTopLeft();
var topRight = info.getTopRight();
var bottomLeft = info.getBottomLeft();
var moduleSize = this.calculateModuleSize(topLeft, topRight, bottomLeft);
if (moduleSize < 1.0) {
throw new NotFoundException_1.default('No pattern found in proccess finder.');
}
var dimension = Detector.computeDimension(topLeft, topRight, bottomLeft, moduleSize);
var provisionalVersion = Version_1.default.getProvisionalVersionForDimension(dimension);
var modulesBetweenFPCenters = provisionalVersion.getDimensionForVersion() - 7;
var alignmentPattern = null;
// Anything above version 1 has an alignment pattern
if (provisionalVersion.getAlignmentPatternCenters().length > 0) {
// Guess where a "bottom right" finder pattern would have been
var bottomRightX = topRight.getX() - topLeft.getX() + bottomLeft.getX();
var bottomRightY = topRight.getY() - topLeft.getY() + bottomLeft.getY();
// Estimate that alignment pattern is closer by 3 modules
// from "bottom right" to known top left location
var correctionToTopLeft = 1.0 - 3.0 / modulesBetweenFPCenters;
var estAlignmentX = /*(int) */ Math.floor(topLeft.getX() + correctionToTopLeft * (bottomRightX - topLeft.getX()));
var estAlignmentY = /*(int) */ Math.floor(topLeft.getY() + correctionToTopLeft * (bottomRightY - topLeft.getY()));
// Kind of arbitrary -- expand search radius before giving up
for (var i = 4; i <= 16; i <<= 1) {
try {
alignmentPattern = this.findAlignmentInRegion(moduleSize, estAlignmentX, estAlignmentY, i);
break;
}
catch (re /*NotFoundException*/) {
if (!(re instanceof NotFoundException_1.default)) {
throw re;
}
// try next round
}
}
// If we didn't find alignment pattern... well try anyway without it
}
var transform = Detector.createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension);
var bits = Detector.sampleGrid(this.image, transform, dimension);
var points;
if (alignmentPattern === null) {
points = [bottomLeft, topLeft, topRight];
}
else {
points = [bottomLeft, topLeft, topRight, alignmentPattern];
}
return new DetectorResult_1.default(bits, points);
};
Detector.createTransform = function (topLeft, topRight, bottomLeft, alignmentPattern, dimension /*int*/) {
var dimMinusThree = dimension - 3.5;
var bottomRightX; /*float*/
var bottomRightY; /*float*/
var sourceBottomRightX; /*float*/
var sourceBottomRightY; /*float*/
if (alignmentPattern !== null) {
bottomRightX = alignmentPattern.getX();
bottomRightY = alignmentPattern.getY();
sourceBottomRightX = dimMinusThree - 3.0;
sourceBottomRightY = sourceBottomRightX;
}
else {
// Don't have an alignment pattern, just make up the bottom-right point
bottomRightX = (topRight.getX() - topLeft.getX()) + bottomLeft.getX();
bottomRightY = (topRight.getY() - topLeft.getY()) + bottomLeft.getY();
sourceBottomRightX = dimMinusThree;
sourceBottomRightY = dimMinusThree;
}
return PerspectiveTransform_1.default.quadrilateralToQuadrilateral(3.5, 3.5, dimMinusThree, 3.5, sourceBottomRightX, sourceBottomRightY, 3.5, dimMinusThree, topLeft.getX(), topLeft.getY(), topRight.getX(), topRight.getY(), bottomRightX, bottomRightY, bottomLeft.getX(), bottomLeft.getY());
};
Detector.sampleGrid = function (image, transform, dimension /*int*/) {
var sampler = GridSamplerInstance_1.default.getInstance();
return sampler.sampleGridWithTransform(image, dimension, dimension, transform);
};
/**
* <p>Computes the dimension (number of modules on a size) of the QR Code based on the position
* of the finder patterns and estimated module size.</p>
*/
Detector.computeDimension = function (topLeft, topRight, bottomLeft, moduleSize /*float*/) {
var tltrCentersDimension = MathUtils_1.default.round(ResultPoint_1.default.distance(topLeft, topRight) / moduleSize);
var tlblCentersDimension = MathUtils_1.default.round(ResultPoint_1.default.distance(topLeft, bottomLeft) / moduleSize);
var dimension = Math.floor((tltrCentersDimension + tlblCentersDimension) / 2) + 7;
switch (dimension & 0x03) { // mod 4
case 0:
dimension++;
break;
// 1? do nothing
case 2:
dimension--;
break;
case 3:
throw new NotFoundException_1.default('Dimensions could be not found.');
}
return dimension;
};
/**
* <p>Computes an average estimated module size based on estimated derived from the positions
* of the three finder patterns.</p>
*
* @param topLeft detected top-left finder pattern center
* @param topRight detected top-right finder pattern center
* @param bottomLeft detected bottom-left finder pattern center
* @return estimated module size
*/
Detector.prototype.calculateModuleSize = function (topLeft, topRight, bottomLeft) {
// Take the average
return (this.calculateModuleSizeOneWay(topLeft, topRight) +
this.calculateModuleSizeOneWay(topLeft, bottomLeft)) / 2.0;
};
/**
* <p>Estimates module size based on two finder patterns -- it uses
* {@link #sizeOfBlackWhiteBlackRunBothWays(int, int, int, int)} to figure the
* width of each, measuring along the axis between their centers.</p>
*/
Detector.prototype.calculateModuleSizeOneWay = function (pattern, otherPattern) {
var moduleSizeEst1 = this.sizeOfBlackWhiteBlackRunBothWays(/*(int) */ Math.floor(pattern.getX()),
/*(int) */ Math.floor(pattern.getY()),
/*(int) */ Math.floor(otherPattern.getX()),
/*(int) */ Math.floor(otherPattern.getY()));
var moduleSizeEst2 = this.sizeOfBlackWhiteBlackRunBothWays(/*(int) */ Math.floor(otherPattern.getX()),
/*(int) */ Math.floor(otherPattern.getY()),
/*(int) */ Math.floor(pattern.getX()),
/*(int) */ Math.floor(pattern.getY()));
if (isNaN(moduleSizeEst1)) {
return moduleSizeEst2 / 7.0;
}
if (isNaN(moduleSizeEst2)) {
return moduleSizeEst1 / 7.0;
}
// Average them, and divide by 7 since we've counted the width of 3 black modules,
// and 1 white and 1 black module on either side. Ergo, divide sum by 14.
return (moduleSizeEst1 + moduleSizeEst2) / 14.0;
};
/**
* See {@link #sizeOfBlackWhiteBlackRun(int, int, int, int)}; computes the total width of
* a finder pattern by looking for a black-white-black run from the center in the direction
* of another point (another finder pattern center), and in the opposite direction too.
*/
Detector.prototype.sizeOfBlackWhiteBlackRunBothWays = function (fromX /*int*/, fromY /*int*/, toX /*int*/, toY /*int*/) {
var result = this.sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY);
// Now count other way -- don't run off image though of course
var scale = 1.0;
var otherToX = fromX - (toX - fromX);
if (otherToX < 0) {
scale = fromX / /*(float) */ (fromX - otherToX);
otherToX = 0;
}
else if (otherToX >= this.image.getWidth()) {
scale = (this.image.getWidth() - 1 - fromX) / /*(float) */ (otherToX - fromX);
otherToX = this.image.getWidth() - 1;
}
var otherToY = /*(int) */ Math.floor(fromY - (toY - fromY) * scale);
scale = 1.0;
if (otherToY < 0) {
scale = fromY / /*(float) */ (fromY - otherToY);
otherToY = 0;
}
else if (otherToY >= this.image.getHeight()) {
scale = (this.image.getHeight() - 1 - fromY) / /*(float) */ (otherToY - fromY);
otherToY = this.image.getHeight() - 1;
}
otherToX = /*(int) */ Math.floor(fromX + (otherToX - fromX) * scale);
result += this.sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY);
// Middle pixel is double-counted this way; subtract 1
return result - 1.0;
};
/**
* <p>This method traces a line from a point in the image, in the direction towards another point.
* It begins in a black region, and keeps going until it finds white, then black, then white again.
* It reports the distance from the start to this point.</p>
*
* <p>This is used when figuring out how wide a finder pattern is, when the finder pattern
* may be skewed or rotated.</p>
*/
Detector.prototype.sizeOfBlackWhiteBlackRun = function (fromX /*int*/, fromY /*int*/, toX /*int*/, toY /*int*/) {
// Mild variant of Bresenham's algorithm
// see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
var steep = Math.abs(toY - fromY) > Math.abs(toX - fromX);
if (steep) {
var temp = fromX;
fromX = fromY;
fromY = temp;
temp = toX;
toX = toY;
toY = temp;
}
var dx = Math.abs(toX - fromX);
var dy = Math.abs(toY - fromY);
var error = -dx / 2;
var xstep = fromX < toX ? 1 : -1;
var ystep = fromY < toY ? 1 : -1;
// In black pixels, looking for white, first or second time.
var state = 0;
// Loop up until x == toX, but not beyond
var xLimit = toX + xstep;
for (var x = fromX, y = fromY; x !== xLimit; x += xstep) {
var realX = steep ? y : x;
var realY = steep ? x : y;
// Does current pixel mean we have moved white to black or vice versa?
// Scanning black in state 0,2 and white in state 1, so if we find the wrong
// color, advance to next state or end if we are in state 2 already
if ((state === 1) === this.image.get(realX, realY)) {
if (state === 2) {
return MathUtils_1.default.distance(x, y, fromX, fromY);
}
state++;
}
error += dy;
if (error > 0) {
if (y === toY) {
break;
}
y += ystep;
error -= dx;
}
}
// Found black-white-black; give the benefit of the doubt that the next pixel outside the image
// is "white" so this last point at (toX+xStep,toY) is the right ending. This is really a
// small approximation; (toX+xStep,toY+yStep) might be really correct. Ignore this.
if (state === 2) {
return MathUtils_1.default.distance(toX + xstep, toY, fromX, fromY);
}
// else we didn't find even black-white-black; no estimate is really possible
return NaN;
};
/**
* <p>Attempts to locate an alignment pattern in a limited region of the image, which is
* guessed to contain it. This method uses {@link AlignmentPattern}.</p>
*
* @param overallEstModuleSize estimated module size so far
* @param estAlignmentX x coordinate of center of area probably containing alignment pattern
* @param estAlignmentY y coordinate of above
* @param allowanceFactor number of pixels in all directions to search from the center
* @return {@link AlignmentPattern} if found, or null otherwise
* @throws NotFoundException if an unexpected error occurs during detection
*/
Detector.prototype.findAlignmentInRegion = function (overallEstModuleSize /*float*/, estAlignmentX /*int*/, estAlignmentY /*int*/, allowanceFactor /*float*/) {
// Look for an alignment pattern (3 modules in size) around where it
// should be
var allowance = /*(int) */ Math.floor(allowanceFactor * overallEstModuleSize);
var alignmentAreaLeftX = Math.max(0, estAlignmentX - allowance);
var alignmentAreaRightX = Math.min(this.image.getWidth() - 1, estAlignmentX + allowance);
if (alignmentAreaRightX - alignmentAreaLeftX < overallEstModuleSize * 3) {
throw new NotFoundException_1.default('Alignment top exceeds estimated module size.');
}
var alignmentAreaTopY = Math.max(0, estAlignmentY - allowance);
var alignmentAreaBottomY = Math.min(this.image.getHeight() - 1, estAlignmentY + allowance);
if (alignmentAreaBottomY - alignmentAreaTopY < overallEstModuleSize * 3) {
throw new NotFoundException_1.default('Alignment bottom exceeds estimated module size.');
}
var alignmentFinder = new AlignmentPatternFinder_1.default(this.image, alignmentAreaLeftX, alignmentAreaTopY, alignmentAreaRightX - alignmentAreaLeftX, alignmentAreaBottomY - alignmentAreaTopY, overallEstModuleSize, this.resultPointCallback);
return alignmentFinder.find();
};
return Detector;
}());
exports.default = Detector;