@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
212 lines (211 loc) • 8.84 kB
JavaScript
/*
* Copyright 2008 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.
*/
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
import OneDReader from './OneDReader';
import NotFoundException from '../NotFoundException';
import FormatException from '../FormatException';
/**
* <p>Encapsulates functionality and implementation that is common to UPC and EAN families
* of one-dimensional barcodes.</p>
*
* @author dswitkin@google.com (Daniel Switkin)
* @author Sean Owen
* @author alasdair@google.com (Alasdair Mackintosh)
*/
var AbstractUPCEANReader = /** @class */ (function (_super) {
__extends(AbstractUPCEANReader, _super);
function AbstractUPCEANReader() {
var _this = _super !== null && _super.apply(this, arguments) || this;
_this.decodeRowStringBuffer = '';
return _this;
}
// private final UPCEANExtensionSupport extensionReader;
// private final EANManufacturerOrgSupport eanManSupport;
/*
protected UPCEANReader() {
decodeRowStringBuffer = new StringBuilder(20);
extensionReader = new UPCEANExtensionSupport();
eanManSupport = new EANManufacturerOrgSupport();
}
*/
AbstractUPCEANReader.findStartGuardPattern = function (row) {
var foundStart = false;
var startRange;
var nextStart = 0;
var counters = Int32Array.from([0, 0, 0]);
while (!foundStart) {
counters = Int32Array.from([0, 0, 0]);
startRange = AbstractUPCEANReader.findGuardPattern(row, nextStart, false, this.START_END_PATTERN, counters);
var start = startRange[0];
nextStart = startRange[1];
var quietStart = start - (nextStart - start);
if (quietStart >= 0) {
foundStart = row.isRange(quietStart, start, false);
}
}
return startRange;
};
AbstractUPCEANReader.checkChecksum = function (s) {
return AbstractUPCEANReader.checkStandardUPCEANChecksum(s);
};
AbstractUPCEANReader.checkStandardUPCEANChecksum = function (s) {
var length = s.length;
if (length === 0)
return false;
var check = parseInt(s.charAt(length - 1), 10);
return AbstractUPCEANReader.getStandardUPCEANChecksum(s.substring(0, length - 1)) === check;
};
AbstractUPCEANReader.getStandardUPCEANChecksum = function (s) {
var length = s.length;
var sum = 0;
for (var i = length - 1; i >= 0; i -= 2) {
var digit = s.charAt(i).charCodeAt(0) - '0'.charCodeAt(0);
if (digit < 0 || digit > 9) {
throw new FormatException();
}
sum += digit;
}
sum *= 3;
for (var i = length - 2; i >= 0; i -= 2) {
var digit = s.charAt(i).charCodeAt(0) - '0'.charCodeAt(0);
if (digit < 0 || digit > 9) {
throw new FormatException();
}
sum += digit;
}
return (1000 - sum) % 10;
};
AbstractUPCEANReader.decodeEnd = function (row, endStart) {
return AbstractUPCEANReader.findGuardPattern(row, endStart, false, AbstractUPCEANReader.START_END_PATTERN, new Int32Array(AbstractUPCEANReader.START_END_PATTERN.length).fill(0));
};
/**
* @throws NotFoundException
*/
AbstractUPCEANReader.findGuardPatternWithoutCounters = function (row, rowOffset, whiteFirst, pattern) {
return this.findGuardPattern(row, rowOffset, whiteFirst, pattern, new Int32Array(pattern.length));
};
/**
* @param row row of black/white values to search
* @param rowOffset position to start search
* @param whiteFirst if true, indicates that the pattern specifies white/black/white/...
* pixel counts, otherwise, it is interpreted as black/white/black/...
* @param pattern pattern of counts of number of black and white pixels that are being
* searched for as a pattern
* @param counters array of counters, as long as pattern, to re-use
* @return start/end horizontal offset of guard pattern, as an array of two ints
* @throws NotFoundException if pattern is not found
*/
AbstractUPCEANReader.findGuardPattern = function (row, rowOffset, whiteFirst, pattern, counters) {
var width = row.getSize();
rowOffset = whiteFirst ? row.getNextUnset(rowOffset) : row.getNextSet(rowOffset);
var counterPosition = 0;
var patternStart = rowOffset;
var patternLength = pattern.length;
var isWhite = whiteFirst;
for (var x = rowOffset; x < width; x++) {
if (row.get(x) !== isWhite) {
counters[counterPosition]++;
}
else {
if (counterPosition === patternLength - 1) {
if (OneDReader.patternMatchVariance(counters, pattern, AbstractUPCEANReader.MAX_INDIVIDUAL_VARIANCE) < AbstractUPCEANReader.MAX_AVG_VARIANCE) {
return Int32Array.from([patternStart, x]);
}
patternStart += counters[0] + counters[1];
var slice = counters.slice(2, counters.length);
for (var i = 0; i < counterPosition - 1; i++) {
counters[i] = slice[i];
}
counters[counterPosition - 1] = 0;
counters[counterPosition] = 0;
counterPosition--;
}
else {
counterPosition++;
}
counters[counterPosition] = 1;
isWhite = !isWhite;
}
}
throw new NotFoundException();
};
AbstractUPCEANReader.decodeDigit = function (row, counters, rowOffset, patterns) {
this.recordPattern(row, rowOffset, counters);
var bestVariance = this.MAX_AVG_VARIANCE;
var bestMatch = -1;
var max = patterns.length;
for (var i = 0; i < max; i++) {
var pattern = patterns[i];
var variance = OneDReader.patternMatchVariance(counters, pattern, AbstractUPCEANReader.MAX_INDIVIDUAL_VARIANCE);
if (variance < bestVariance) {
bestVariance = variance;
bestMatch = i;
}
}
if (bestMatch >= 0) {
return bestMatch;
}
else {
throw new NotFoundException();
}
};
// These two values are critical for determining how permissive the decoding will be.
// We've arrived at these values through a lot of trial and error. Setting them any higher
// lets false positives creep in quickly.
AbstractUPCEANReader.MAX_AVG_VARIANCE = 0.48;
AbstractUPCEANReader.MAX_INDIVIDUAL_VARIANCE = 0.7;
/**
* Start/end guard pattern.
*/
AbstractUPCEANReader.START_END_PATTERN = Int32Array.from([1, 1, 1]);
/**
* Pattern marking the middle of a UPC/EAN pattern, separating the two halves.
*/
AbstractUPCEANReader.MIDDLE_PATTERN = Int32Array.from([1, 1, 1, 1, 1]);
/**
* end guard pattern.
*/
AbstractUPCEANReader.END_PATTERN = Int32Array.from([1, 1, 1, 1, 1, 1]);
/**
* "Odd", or "L" patterns used to encode UPC/EAN digits.
*/
AbstractUPCEANReader.L_PATTERNS = [
Int32Array.from([3, 2, 1, 1]),
Int32Array.from([2, 2, 2, 1]),
Int32Array.from([2, 1, 2, 2]),
Int32Array.from([1, 4, 1, 1]),
Int32Array.from([1, 1, 3, 2]),
Int32Array.from([1, 2, 3, 1]),
Int32Array.from([1, 1, 1, 4]),
Int32Array.from([1, 3, 1, 2]),
Int32Array.from([1, 2, 1, 3]),
Int32Array.from([3, 1, 1, 2]),
];
return AbstractUPCEANReader;
}(OneDReader));
export default AbstractUPCEANReader;