@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
195 lines (194 loc) • 8.22 kB
JavaScript
/*
* 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.
*/
/*namespace com.google.zxing.qrcode {*/
import BarcodeFormat from '../BarcodeFormat';
import BitMatrix from '../common/BitMatrix';
import DecodeHintType from '../DecodeHintType';
import NotFoundException from '../NotFoundException';
import Result from '../Result';
import ResultMetadataType from '../ResultMetadataType';
// import DetectorResult from '../common/DetectorResult';
import Decoder from './decoder/Decoder';
import QRCodeDecoderMetaData from './decoder/QRCodeDecoderMetaData';
import Detector from './detector/Detector';
/*import java.util.List;*/
/*import java.util.Map;*/
/**
* This implementation can detect and decode QR Codes in an image.
*
* @author Sean Owen
*/
var QRCodeReader = /** @class */ (function () {
function QRCodeReader() {
this.decoder = new Decoder();
}
QRCodeReader.prototype.getDecoder = function () {
return this.decoder;
};
/**
* Locates and decodes a QR code in an image.
*
* @return a representing: string the content encoded by the QR code
* @throws NotFoundException if a QR code cannot be found
* @throws FormatException if a QR code cannot be decoded
* @throws ChecksumException if error correction fails
*/
/*@Override*/
// public decode(image: BinaryBitmap): Result /*throws NotFoundException, ChecksumException, FormatException */ {
// return this.decode(image, null)
// }
/*@Override*/
QRCodeReader.prototype.decode = function (image, hints) {
var decoderResult;
var points;
if (hints !== undefined && hints !== null && undefined !== hints.get(DecodeHintType.PURE_BARCODE)) {
var bits = QRCodeReader.extractPureBits(image.getBlackMatrix());
decoderResult = this.decoder.decodeBitMatrix(bits, hints);
points = QRCodeReader.NO_POINTS;
}
else {
var detectorResult = new Detector(image.getBlackMatrix()).detect(hints);
decoderResult = this.decoder.decodeBitMatrix(detectorResult.getBits(), hints);
points = detectorResult.getPoints();
}
// If the code was mirrored: swap the bottom-left and the top-right points.
if (decoderResult.getOther() instanceof QRCodeDecoderMetaData) {
decoderResult.getOther().applyMirroredCorrection(points);
}
var result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), undefined, points, BarcodeFormat.QR_CODE, undefined);
var byteSegments = decoderResult.getByteSegments();
if (byteSegments !== null) {
result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, byteSegments);
}
var ecLevel = decoderResult.getECLevel();
if (ecLevel !== null) {
result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
}
if (decoderResult.hasStructuredAppend()) {
result.putMetadata(ResultMetadataType.STRUCTURED_APPEND_SEQUENCE, decoderResult.getStructuredAppendSequenceNumber());
result.putMetadata(ResultMetadataType.STRUCTURED_APPEND_PARITY, decoderResult.getStructuredAppendParity());
}
return result;
};
/*@Override*/
QRCodeReader.prototype.reset = function () {
// do nothing
};
/**
* This method detects a code in a "pure" image -- that is, pure monochrome image
* which contains only an unrotated, unskewed, image of a code, with some white border
* around it. This is a specialized method that works exceptionally fast in this special
* case.
*
* @see com.google.zxing.datamatrix.DataMatrixReader#extractPureBits(BitMatrix)
*/
QRCodeReader.extractPureBits = function (image) {
var leftTopBlack = image.getTopLeftOnBit();
var rightBottomBlack = image.getBottomRightOnBit();
if (leftTopBlack === null || rightBottomBlack === null) {
throw new NotFoundException();
}
var moduleSize = this.moduleSize(leftTopBlack, image);
var top = leftTopBlack[1];
var bottom = rightBottomBlack[1];
var left = leftTopBlack[0];
var right = rightBottomBlack[0];
// Sanity check!
if (left >= right || top >= bottom) {
throw new NotFoundException();
}
if (bottom - top !== right - left) {
// Special case, where bottom-right module wasn't black so we found something else in the last row
// Assume it's a square, so use height as the width
right = left + (bottom - top);
if (right >= image.getWidth()) {
// Abort if that would not make sense -- off image
throw new NotFoundException();
}
}
var matrixWidth = Math.round((right - left + 1) / moduleSize);
var matrixHeight = Math.round((bottom - top + 1) / moduleSize);
if (matrixWidth <= 0 || matrixHeight <= 0) {
throw new NotFoundException();
}
if (matrixHeight !== matrixWidth) {
// Only possibly decode square regions
throw new NotFoundException();
}
// Push in the "border" by half the module width so that we start
// sampling in the middle of the module. Just in case the image is a
// little off, this will help recover.
var nudge = /*(int) */ Math.floor(moduleSize / 2.0);
top += nudge;
left += nudge;
// But careful that this does not sample off the edge
// "right" is the farthest-right valid pixel location -- right+1 is not necessarily
// This is positive by how much the inner x loop below would be too large
var nudgedTooFarRight = left + /*(int) */ Math.floor((matrixWidth - 1) * moduleSize) - right;
if (nudgedTooFarRight > 0) {
if (nudgedTooFarRight > nudge) {
// Neither way fits; abort
throw new NotFoundException();
}
left -= nudgedTooFarRight;
}
// See logic above
var nudgedTooFarDown = top + /*(int) */ Math.floor((matrixHeight - 1) * moduleSize) - bottom;
if (nudgedTooFarDown > 0) {
if (nudgedTooFarDown > nudge) {
// Neither way fits; abort
throw new NotFoundException();
}
top -= nudgedTooFarDown;
}
// Now just read off the bits
var bits = new BitMatrix(matrixWidth, matrixHeight);
for (var y = 0; y < matrixHeight; y++) {
var iOffset = top + /*(int) */ Math.floor(y * moduleSize);
for (var x = 0; x < matrixWidth; x++) {
if (image.get(left + /*(int) */ Math.floor(x * moduleSize), iOffset)) {
bits.set(x, y);
}
}
}
return bits;
};
QRCodeReader.moduleSize = function (leftTopBlack, image) {
var height = image.getHeight();
var width = image.getWidth();
var x = leftTopBlack[0];
var y = leftTopBlack[1];
var inBlack = true;
var transitions = 0;
while (x < width && y < height) {
if (inBlack !== image.get(x, y)) {
if (++transitions === 5) {
break;
}
inBlack = !inBlack;
}
x++;
y++;
}
if (x === width || y === height) {
throw new NotFoundException();
}
return (x - leftTopBlack[0]) / 7.0;
};
QRCodeReader.NO_POINTS = new Array();
return QRCodeReader;
}());
export default QRCodeReader;