@zxing/library
Version:
TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
72 lines (71 loc) • 2.93 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.detector {*/
import ResultPoint from '../../ResultPoint';
/**
* <p>Encapsulates a finder pattern, which are the three square patterns found in
* the corners of QR Codes. It also encapsulates a count of similar finder patterns,
* as a convenience to the finder's bookkeeping.</p>
*
* @author Sean Owen
*/
export default class FinderPattern extends ResultPoint {
// FinderPattern(posX: number/*float*/, posY: number/*float*/, estimatedModuleSize: number/*float*/) {
// this(posX, posY, estimatedModuleSize, 1)
// }
constructor(posX /*float*/, posY /*float*/, estimatedModuleSize /*float*/, count /*int*/) {
super(posX, posY);
this.estimatedModuleSize = estimatedModuleSize;
this.count = count;
if (undefined === count) {
this.count = 1;
}
}
getEstimatedModuleSize() {
return this.estimatedModuleSize;
}
getCount() {
return this.count;
}
/*
void incrementCount() {
this.count++
}
*/
/**
* <p>Determines if this finder pattern "about equals" a finder pattern at the stated
* position and size -- meaning, it is at nearly the same center with nearly the same size.</p>
*/
aboutEquals(moduleSize /*float*/, i /*float*/, j /*float*/) {
if (Math.abs(i - this.getY()) <= moduleSize && Math.abs(j - this.getX()) <= moduleSize) {
const moduleSizeDiff = Math.abs(moduleSize - this.estimatedModuleSize);
return moduleSizeDiff <= 1.0 || moduleSizeDiff <= this.estimatedModuleSize;
}
return false;
}
/**
* Combines this object's current estimate of a finder pattern position and module size
* with a new estimate. It returns a new {@code FinderPattern} containing a weighted average
* based on count.
*/
combineEstimate(i /*float*/, j /*float*/, newModuleSize /*float*/) {
const combinedCount = this.count + 1;
const combinedX = (this.count * this.getX() + j) / combinedCount;
const combinedY = (this.count * this.getY() + i) / combinedCount;
const combinedModuleSize = (this.count * this.estimatedModuleSize + newModuleSize) / combinedCount;
return new FinderPattern(combinedX, combinedY, combinedModuleSize, combinedCount);
}
}