sports-miniapp/node_modules/qrcode-reader/src/grid.js

/*
  Ported to JavaScript by Lazar Laszlo 2011

  lazarsoft@gmail.com, www.lazarsoft.info

*/

/*
*
* 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.
*/

import BitMatrix from './bitmat';

var GridSampler = {};

GridSampler.checkAndNudgePoints = function(image,  points) {
  var width = image.width;
  var height = image.height;
  // 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 "Error.checkAndNudgePoints ";
    }
    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 "Error.checkAndNudgePoints ";
    }
    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;
    }
  }
};



GridSampler.sampleGrid3 = function(image,  dimension,  transform) {
  var bits = new BitMatrix(dimension);
  var points = new Array(dimension << 1);
  for (var y = 0; y < dimension; y++) {
    var max = points.length;
    var iValue =  y + 0.5;
    for (var x = 0; x < max; x += 2) {
      points[x] =  (x >> 1) + 0.5;
      points[x + 1] = iValue;
    }
    transform.transformPoints1(points);
    // Quick check to see if points transformed to something inside the image
    // sufficient to check the endpoints
    GridSampler.checkAndNudgePoints(image, points);
    try {
      for (var x = 0; x < max; x += 2) {
        var bit = image.data[Math.floor(points[x]) + image.width * Math.floor(points[x + 1])];
        if (bit)
          bits.set_Renamed(x >> 1, y);
      }
    } catch (aioobe) {
      // This feels wrong, but, sometimes if the finder patterns are misidentified, the resulting
      // transform gets "twisted" such that it maps a straight line of points to a set of points
      // whose endpoints are in bounds, but others are not. There is probably some mathematical
      // way to detect this about the transformation that I don't know yet.
      // This results in an ugly runtime exception despite our clever checks above -- can't have
      // that. We could check each point's coordinates but that feels duplicative. We settle for
      // catching and wrapping ArrayIndexOutOfBoundsException.
      throw "Error.checkAndNudgePoints";
    }
  }
  return bits;
};

export default GridSampler;