import 'babel-polyfill'; import * as POTRACE from 'potrace-js'; import { POTRACE_OPTIONS } from '../src/constants/d2Constants.js'; self.addEventListener('message', (event) => { switch (event.data.msg) { case 'FLOOD_FILL': const { imageData, start, tolerance } = event.data; self.postMessage({ msg: 'FLOOD_FILL', status: 'OK', traceData: floodFill(imageData, start, tolerance) }); break; case 'TRACE': const { fill, width, height } = event.data; const bitmap = new POTRACE.Bitmap(width, height); for (let i = 0; i < fill.length; i ++) { const index = fill[i]; bitmap.data[index] = 1; } self.postMessage({ msg: 'TRACE', status: 'OK', paths: POTRACE.getPaths(POTRACE.traceBitmap(bitmap, POTRACE_OPTIONS)) }); break; default: break; } }); function floodFill(imageData, start, tolerance) { const { width, height } = imageData; const compairIndex = start.y * width + start.x; const stack = [compairIndex]; const done = { [compairIndex]: true }; const edge = []; const fill = []; while (stack.length > 0) { const index = stack.pop(); const value = imageData.data[index]; const pass = value < tolerance; if (!pass) { edge.push(index); continue; } fill.push(index); const left = index % width !== 0; const right = index % width !== width - 1; const top = Math.floor(index / width) !== 0; const bottom = Math.floor(index / width) !== height - 1; const neighbours = []; if (left) neighbours.push(index - 1); if (right) neighbours.push(index + 1); if (top) neighbours.push(index - width); if (bottom) neighbours.push(index + width); if (neighbours.length !== 4) edge.push(index); for (let i = 0; i < neighbours.length; i ++) { const neighbourIndex = neighbours[i]; if (!done[neighbourIndex]) { stack.push(neighbourIndex); } done[neighbourIndex] = true; } } return { edge, fill }; }