kopia lustrzana https://github.com/rastapasta/mapscii
203 wiersze
5.2 KiB
JavaScript
203 wiersze
5.2 KiB
JavaScript
/*
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termap - Terminal Map Viewer
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by Michael Strassburger <codepoet@cpan.org>
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Canvas-like painting abstraction for BrailleBuffer
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Implementation inspired by node-drawille-canvas (https://github.com/madbence/node-drawille-canvas)
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* added support for filled polygons
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* improved text rendering
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Will most likely be turned into a stand alone module at some point
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*/
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'use strict';
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const bresenham = require('bresenham');
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const earcut = require('earcut');
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const BrailleBuffer = require('./BrailleBuffer');
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class Canvas {
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constructor(width, height) {
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this.width = width;
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this.height = height;
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this.buffer = new BrailleBuffer(width, height);
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}
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frame() {
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return this.buffer.frame();
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}
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clear() {
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this.buffer.clear();
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}
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text(text, x, y, color, center = false) {
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this.buffer.writeText(text, x, y, color, center);
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}
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line(from, to, color, width = 1) {
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this._line(from.x, from.y, to.x, to.y, color, width);
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}
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polyline(points, color, width = 1) {
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for (let i = 1; i < points.length; i++) {
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const x1 = points[i - 1].x;
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const y1 = points[i - 1].y;
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this._line(x1, y1, points[i].x, points[i].y, width, color);
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}
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}
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setBackground(color) {
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this.buffer.setGlobalBackground(color);
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}
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background(x, y, color) {
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this.buffer.setBackground(x, y, color);
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}
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polygon(rings, color) {
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const vertices = [];
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const holes = [];
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for (const ring of rings) {
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if (vertices.length) {
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if (ring.length < 3) continue;
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holes.push(vertices.length / 2);
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} else {
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if (ring.length < 3) return false;
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}
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for (const point of ring) {
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vertices.push(point.x);
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vertices.push(point.y);
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}
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}
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let triangles;
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try {
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triangles = earcut(vertices, holes);
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} catch (error) {
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return false;
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}
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for (let i = 0; i < triangles.length; i += 3) {
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const pa = this._polygonExtract(vertices, triangles[i]);
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const pb = this._polygonExtract(vertices, triangles[i + 1]);
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const pc = this._polygonExtract(vertices, triangles[i + 2]);
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this._filledTriangle(pa, pb, pc, color);
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}
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return true;
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}
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_polygonExtract(vertices, pointId) {
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return [vertices[pointId * 2], vertices[pointId * 2 + 1]];
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}
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// Inspired by Alois Zingl's "The Beauty of Bresenham's Algorithm"
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// -> http://members.chello.at/~easyfilter/bresenham.html
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_line(x0, y0, x1, y1, width, color) {
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// Fall back to width-less bresenham algorithm if we dont have a width
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if (!(width = Math.max(0, width - 1))) {
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return bresenham(x0, y0, x1, y1, (x, y) => {
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return this.buffer.setPixel(x, y, color);
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});
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}
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const dx = Math.abs(x1 - x0);
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const sx = x0 < x1 ? 1 : -1;
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const dy = Math.abs(y1 - y0);
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const sy = y0 < y1 ? 1 : -1;
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let err = dx - dy;
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const ed = dx + dy === 0 ? 1 : Math.sqrt(dx * dx + dy * dy);
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width = (width + 1) / 2;
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/* eslint-disable no-constant-condition */
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while (true) {
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this.buffer.setPixel(x0, y0, color);
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let e2 = err;
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let x2 = x0;
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if (2 * e2 >= -dx) {
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e2 += dy;
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let y2 = y0;
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while (e2 < ed * width && (y1 !== y2 || dx > dy)) {
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this.buffer.setPixel(x0, y2 += sy, color);
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e2 += dx;
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}
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if (x0 === x1) {
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break;
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}
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e2 = err;
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err -= dy;
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x0 += sx;
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}
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if (2 * e2 <= dy) {
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e2 = dx - e2;
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while (e2 < ed * width && (x1 !== x2 || dx < dy)) {
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this.buffer.setPixel(x2 += sx, y0, color);
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e2 += dy;
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}
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if (y0 === y1) {
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break;
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}
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err += dx;
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y0 += sy;
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}
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}
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/* eslint-enable */
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}
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_filledRectangle(x, y, width, height, color) {
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const pointA = [x, y];
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const pointB = [x + width, y];
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const pointC = [x, y + height];
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const pointD = [x + width, y + height];
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this._filledTriangle(pointA, pointB, pointC, color);
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this._filledTriangle(pointC, pointB, pointD, color);
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}
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_bresenham(pointA, pointB) {
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return bresenham(pointA[0], pointA[1], pointB[0], pointB[1]);
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}
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// Draws a filled triangle
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_filledTriangle(pointA, pointB, pointC, color) {
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const a = this._bresenham(pointB, pointC);
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const b = this._bresenham(pointA, pointC);
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const c = this._bresenham(pointA, pointB);
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const points = a.concat(b).concat(c).filter((point) => {
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var ref;
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return (0 <= (ref = point.y) && ref < this.height);
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}).sort(function(a, b) {
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if (a.y === b.y) {
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return a.x - b.x;
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} else {
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return a.y - b.y;
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}
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});
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for (let i = 0; i < points.length; i++) {
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const point = points[i];
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const next = points[i * 1 + 1];
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if (point.y === (next || {}).y) {
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const left = Math.max(0, point.x);
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const right = Math.min(this.width - 1, next.x);
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if (left >= 0 && right <= this.width) {
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for (let x = left; x <= right; x++) {
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this.buffer.setPixel(x, point.y, color);
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}
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}
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} else {
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this.buffer.setPixel(point.x, point.y, color);
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}
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if (!next) {
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break;
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}
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}
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}
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}
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Canvas.prototype.stack = [];
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module.exports = Canvas;
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