@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
211 lines (210 loc) • 8.04 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.
*/
import IllegalArgumentException from '../../IllegalArgumentException';
/**
* @author Satoru Takabayashi
* @author Daniel Switkin
* @author Sean Owen
*/
export default class MaskUtil {
constructor() {
// do nothing
}
/**
* Apply mask penalty rule 1 and return the penalty. Find repetitive cells with the same color and
* give penalty to them. Example: 00000 or 11111.
*/
static applyMaskPenaltyRule1(matrix) {
return MaskUtil.applyMaskPenaltyRule1Internal(matrix, true) + MaskUtil.applyMaskPenaltyRule1Internal(matrix, false);
}
/**
* Apply mask penalty rule 2 and return the penalty. Find 2x2 blocks with the same color and give
* penalty to them. This is actually equivalent to the spec's rule, which is to find MxN blocks and give a
* penalty proportional to (M-1)x(N-1), because this is the number of 2x2 blocks inside such a block.
*/
static applyMaskPenaltyRule2(matrix) {
let penalty = 0;
const array = matrix.getArray();
const width = matrix.getWidth();
const height = matrix.getHeight();
for (let y = 0; y < height - 1; y++) {
const arrayY = array[y];
for (let x = 0; x < width - 1; x++) {
const value = arrayY[x];
if (value === arrayY[x + 1] && value === array[y + 1][x] && value === array[y + 1][x + 1]) {
penalty++;
}
}
}
return MaskUtil.N2 * penalty;
}
/**
* Apply mask penalty rule 3 and return the penalty. Find consecutive runs of 1:1:3:1:1:4
* starting with black, or 4:1:1:3:1:1 starting with white, and give penalty to them. If we
* find patterns like 000010111010000, we give penalty once.
*/
static applyMaskPenaltyRule3(matrix) {
let numPenalties = 0;
const array = matrix.getArray();
const width = matrix.getWidth();
const height = matrix.getHeight();
for (let y = 0; y < height; y++) {
for (let x = 0; x < width; x++) {
const arrayY = array[y]; // We can at least optimize this access
if (x + 6 < width &&
arrayY[x] === 1 &&
arrayY[x + 1] === 0 &&
arrayY[x + 2] === 1 &&
arrayY[x + 3] === 1 &&
arrayY[x + 4] === 1 &&
arrayY[x + 5] === 0 &&
arrayY[x + 6] === 1 &&
(MaskUtil.isWhiteHorizontal(arrayY, x - 4, x) || MaskUtil.isWhiteHorizontal(arrayY, x + 7, x + 11))) {
numPenalties++;
}
if (y + 6 < height &&
array[y][x] === 1 &&
array[y + 1][x] === 0 &&
array[y + 2][x] === 1 &&
array[y + 3][x] === 1 &&
array[y + 4][x] === 1 &&
array[y + 5][x] === 0 &&
array[y + 6][x] === 1 &&
(MaskUtil.isWhiteVertical(array, x, y - 4, y) || MaskUtil.isWhiteVertical(array, x, y + 7, y + 11))) {
numPenalties++;
}
}
}
return numPenalties * MaskUtil.N3;
}
static isWhiteHorizontal(rowArray, from /*int*/, to /*int*/) {
from = Math.max(from, 0);
to = Math.min(to, rowArray.length);
for (let i = from; i < to; i++) {
if (rowArray[i] === 1) {
return false;
}
}
return true;
}
static isWhiteVertical(array, col /*int*/, from /*int*/, to /*int*/) {
from = Math.max(from, 0);
to = Math.min(to, array.length);
for (let i = from; i < to; i++) {
if (array[i][col] === 1) {
return false;
}
}
return true;
}
/**
* Apply mask penalty rule 4 and return the penalty. Calculate the ratio of dark cells and give
* penalty if the ratio is far from 50%. It gives 10 penalty for 5% distance.
*/
static applyMaskPenaltyRule4(matrix) {
let numDarkCells = 0;
const array = matrix.getArray();
const width = matrix.getWidth();
const height = matrix.getHeight();
for (let y = 0; y < height; y++) {
const arrayY = array[y];
for (let x = 0; x < width; x++) {
if (arrayY[x] === 1) {
numDarkCells++;
}
}
}
const numTotalCells = matrix.getHeight() * matrix.getWidth();
const fivePercentVariances = Math.floor(Math.abs(numDarkCells * 2 - numTotalCells) * 10 / numTotalCells);
return fivePercentVariances * MaskUtil.N4;
}
/**
* Return the mask bit for "getMaskPattern" at "x" and "y". See 8.8 of JISX0510:2004 for mask
* pattern conditions.
*/
static getDataMaskBit(maskPattern /*int*/, x /*int*/, y /*int*/) {
let intermediate; /*int*/
let temp; /*int*/
switch (maskPattern) {
case 0:
intermediate = (y + x) & 0x1;
break;
case 1:
intermediate = y & 0x1;
break;
case 2:
intermediate = x % 3;
break;
case 3:
intermediate = (y + x) % 3;
break;
case 4:
intermediate = (Math.floor(y / 2) + Math.floor(x / 3)) & 0x1;
break;
case 5:
temp = y * x;
intermediate = (temp & 0x1) + (temp % 3);
break;
case 6:
temp = y * x;
intermediate = ((temp & 0x1) + (temp % 3)) & 0x1;
break;
case 7:
temp = y * x;
intermediate = ((temp % 3) + ((y + x) & 0x1)) & 0x1;
break;
default:
throw new IllegalArgumentException('Invalid mask pattern: ' + maskPattern);
}
return intermediate === 0;
}
/**
* Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
* vertical and horizontal orders respectively.
*/
static applyMaskPenaltyRule1Internal(matrix, isHorizontal) {
let penalty = 0;
const iLimit = isHorizontal ? matrix.getHeight() : matrix.getWidth();
const jLimit = isHorizontal ? matrix.getWidth() : matrix.getHeight();
const array = matrix.getArray();
for (let i = 0; i < iLimit; i++) {
let numSameBitCells = 0;
let prevBit = -1;
for (let j = 0; j < jLimit; j++) {
const bit = isHorizontal ? array[i][j] : array[j][i];
if (bit === prevBit) {
numSameBitCells++;
}
else {
if (numSameBitCells >= 5) {
penalty += MaskUtil.N1 + (numSameBitCells - 5);
}
numSameBitCells = 1; // Include the cell itself.
prevBit = bit;
}
}
if (numSameBitCells >= 5) {
penalty += MaskUtil.N1 + (numSameBitCells - 5);
}
}
return penalty;
}
}
// Penalty weights from section 6.8.2.1
MaskUtil.N1 = 3;
MaskUtil.N2 = 3;
MaskUtil.N3 = 40;
MaskUtil.N4 = 10;