@antv/l7-utils/lib/color.js

"use strict";

var _interopRequireWildcard = require("@babel/runtime/helpers/interopRequireWildcard");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.rgb2arr = rgb2arr;
exports.decodePickingColor = decodePickingColor;
exports.encodePickingColor = encodePickingColor;
exports.generateColorRamp = generateColorRamp;

var d3 = _interopRequireWildcard(require("d3-color"));

function rgb2arr(str) {
  var color = d3.color(str);
  var arr = [0, 0, 0, 0];

  if (color != null) {
    arr[0] = color.r / 255;
    arr[1] = color.g / 255;
    arr[2] = color.b / 255;
    arr[3] = color.opacity;
  }

  return arr;
}

function decodePickingColor(color) {
  var i1 = color && color[0];
  var i2 = color && color[1];
  var i3 = color && color[2];
  var index = i1 + i2 * 256 + i3 * 65536 - 1;
  return index;
}

function encodePickingColor(featureIdx) {
  return [featureIdx + 1 & 255, featureIdx + 1 >> 8 & 255, featureIdx + 1 >> 8 >> 8 & 255];
}

function generateColorRamp(colorRamp) {
  var canvas = document.createElement('canvas');
  var ctx = canvas.getContext('2d');
  canvas.width = 256;
  canvas.height = 1;
  var gradient = ctx.createLinearGradient(0, 0, 256, 1);
  var data = null;
  var min = colorRamp.positions[0];
  var max = colorRamp.positions[colorRamp.positions.length - 1];

  for (var i = 0; i < colorRamp.colors.length; ++i) {
    var value = (colorRamp.positions[i] - min) / (max - min);
    gradient.addColorStop(value, colorRamp.colors[i]);
  }

  ctx.fillStyle = gradient;
  ctx.fillRect(0, 0, 256, 1);
  data = new Uint8ClampedArray(ctx.getImageData(0, 0, 256, 1).data);
  return new ImageData(data, 256, 1);
}
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