@zxing/library
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TypeScript port of ZXing multi-format 1D/2D barcode image processing library.
109 lines (108 loc) • 4.45 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.
*/
Object.defineProperty(exports, "__esModule", { value: true });
var NotFoundException_1 = require("../NotFoundException");
/**
* Implementations of this class can, given locations of finder patterns for a QR code in an
* image, sample the right points in the image to reconstruct the QR code, accounting for
* perspective distortion. It is abstracted since it is relatively expensive and should be allowed
* to take advantage of platform-specific optimized implementations, like Sun's Java Advanced
* Imaging library, but which may not be available in other environments such as J2ME, and vice
* versa.
*
* The implementation used can be controlled by calling {@link #setGridSampler(GridSampler)}
* with an instance of a class which implements this interface.
*
* @author Sean Owen
*/
var GridSampler = /** @class */ (function () {
function GridSampler() {
}
/**
* <p>Checks a set of points that have been transformed to sample points on an image against
* the image's dimensions to see if the point are even within the image.</p>
*
* <p>This method will actually "nudge" the endpoints back onto the image if they are found to be
* barely (less than 1 pixel) off the image. This accounts for imperfect detection of finder
* patterns in an image where the QR Code runs all the way to the image border.</p>
*
* <p>For efficiency, the method will check points from either end of the line until one is found
* to be within the image. Because the set of points are assumed to be linear, this is valid.</p>
*
* @param image image into which the points should map
* @param points actual points in x1,y1,...,xn,yn form
* @throws NotFoundException if an endpoint is lies outside the image boundaries
*/
GridSampler.checkAndNudgePoints = function (image, points) {
var width = image.getWidth();
var height = image.getHeight();
// Check and nudge points from start until we see some that are OK:
var nudged = true;
for (var offset = 0; offset < points.length && nudged; offset += 2) {
var x = Math.floor(points[offset]);
var y = Math.floor(points[offset + 1]);
if (x < -1 || x > width || y < -1 || y > height) {
throw new NotFoundException_1.default();
}
nudged = false;
if (x === -1) {
points[offset] = 0.0;
nudged = true;
}
else if (x === width) {
points[offset] = width - 1;
nudged = true;
}
if (y === -1) {
points[offset + 1] = 0.0;
nudged = true;
}
else if (y === height) {
points[offset + 1] = height - 1;
nudged = true;
}
}
// Check and nudge points from end:
nudged = true;
for (var offset = points.length - 2; offset >= 0 && nudged; offset -= 2) {
var x = Math.floor(points[offset]);
var y = Math.floor(points[offset + 1]);
if (x < -1 || x > width || y < -1 || y > height) {
throw new NotFoundException_1.default();
}
nudged = false;
if (x === -1) {
points[offset] = 0.0;
nudged = true;
}
else if (x === width) {
points[offset] = width - 1;
nudged = true;
}
if (y === -1) {
points[offset + 1] = 0.0;
nudged = true;
}
else if (y === height) {
points[offset + 1] = height - 1;
nudged = true;
}
}
};
return GridSampler;
}());
exports.default = GridSampler;