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Copy pathgraph.ts
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298 lines (260 loc) · 7.91 KB
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// Copyright 2019 Google LLC
//
// 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 {Nullable} from './base'
import {Position} from './position'
import {getElement, pixelRatio} from './util'
import {View} from './view'
namespace Graph {
export interface GraphOptions {
xStart: number;
xEnd: number;
yStart: number;
yEnd: number;
xTicks?: boolean;
yTicks?: boolean;
marginTop?: number;
marginBottom?: number;
marginLeft?: number;
marginRight?: number;
}
export type Point = number[];
export interface PlotOptions {
width?: number;
style?: string;
snap?: boolean;
dash?: number[];
}
}
const DEFAULT_PLOT_OPTIONS: Graph.PlotOptions = {
width: 1,
snap: false,
};
abstract class Graph extends View {
protected ctx: CanvasRenderingContext2D;
private marginTopPct: number;
private marginBottomPct: number;
private marginLeftPct: number;
private marginRightPct: number;
private xTicks: boolean;
private yTicks: boolean;
private lineDash = false;
protected xScale: number;
protected yScale: number;
protected xTickPoints: number[] = [];
protected yTickPoints: number[] = [];
protected marginTop: number;
protected marginBottom: number;
protected marginLeft: number;
protected marginRight: number;
protected xStart = 0;
protected xEnd = 1;
protected yStart = 0;
protected yEnd = 1;
protected moveNum = 0;
constructor(parent: HTMLElement | string, private options: Graph.GraphOptions) {
super();
this.xStart = options.xStart;
this.xEnd = options.xEnd;
this.yStart = options.yStart;
this.yEnd = options.yEnd;
this.xTicks = options.xTicks || false;
this.yTicks = options.yTicks || false;
this.marginTopPct = options.marginTop || 0.05;
this.marginBottomPct = options.marginBottom || 0.05;
this.marginLeftPct = options.marginLeft || 0.05;
this.marginRightPct = options.marginRight || 0.05;
if (typeof(parent) == 'string') {
parent = getElement(parent);
}
let canvas = document.createElement('canvas');
this.ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
parent.appendChild(canvas);
this.resizeCanvas();
window.addEventListener('resize', () => {
this.resizeCanvas();
this.draw();
});
this.draw();
}
private resizeCanvas() {
let pr = pixelRatio();
let ctx = this.ctx;
let canvas = ctx.canvas;
let parent = canvas.parentElement as HTMLElement;
canvas.width = pr * parent.offsetWidth;
canvas.height = pr * parent.offsetHeight;
canvas.style.width = `${parent.offsetWidth}px`;
canvas.style.height = `${parent.offsetHeight}px`;
this.marginTop = Math.floor(this.marginTopPct * canvas.width);
this.marginBottom = Math.floor(this.marginBottomPct * canvas.width);
this.marginLeft = Math.floor(this.marginLeftPct * canvas.width);
this.marginRight = Math.floor(this.marginRightPct * canvas.width);
let w = canvas.width - this.marginLeft - this.marginRight;
let h = canvas.height - this.marginTop - this.marginBottom;
this.xScale = w / (this.xEnd - this.xStart);
this.yScale = h / (this.yEnd - this.yStart);
ctx.lineCap = 'round';
ctx.lineJoin = 'round';
}
setMoveNum(moveNum: number) {
if (moveNum != this.moveNum) {
this.moveNum = moveNum;
this.draw();
}
}
drawImpl() {
this.updateScale();
let pr = pixelRatio();
let ctx = this.ctx;
ctx.setTransform(1, 0, 0, 1, 0, 0);
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
// Apply a translation such that (0, 0) is the center of the pixel at the
// top left of the graph.
ctx.translate(this.marginLeft + 0.5, this.marginTop + 0.5);
ctx.lineWidth = pr;
ctx.strokeStyle = '#96928f';
this.beginPath();
this.moveTo(this.xStart, 0, true);
this.lineTo(this.xEnd, 0, true);
this.moveTo(0, this.yStart, true);
this.lineTo(0, this.yEnd, true);
if (this.xTicks) {
this.xTickPoints = this.calculateTickPoints(this.xStart, this.xEnd);
let y = 4 * pr / this.yScale;
if (this.yEnd > this.yStart) {
y = -y;
}
for (let x of this.xTickPoints) {
this.moveTo(x, 0, true);
this.lineTo(x, y, true);
}
}
if (this.yTicks) {
this.yTickPoints = this.calculateTickPoints(this.yStart, this.yEnd);
let x = 4 * pr / this.xScale;
if (this.xEnd > this.xStart) {
x = -x;
}
for (let y of this.yTickPoints) {
this.moveTo(0, y, true);
this.lineTo(x, y, true);
}
}
this.stroke();
}
protected drawText(text: string, x: number, y: number, snap=false) {
x = this.xScale * (x - this.xStart);
y = this.yScale * (y - this.yStart);
if (snap) {
x = Math.round(x);
y = Math.round(y);
}
this.ctx.fillText(text, x, y);
}
protected drawPlot(points: Graph.Point[], options=DEFAULT_PLOT_OPTIONS) {
if (points.length == 0) {
return;
}
let pr = pixelRatio();
let ctx = this.ctx;
let snap = options.snap || false;
ctx.lineWidth = (options.width || 1) * pr;
if (options.style) {
ctx.strokeStyle = options.style;
}
this.beginPath(options.dash || null);
this.moveTo(points[0][0], points[0][1], snap);
for (let i = Math.min(1, points.length - 1); i < points.length; ++i) {
let p = points[i];
this.lineTo(p[0], p[1], snap);
}
this.stroke();
}
private beginPath(dash: Nullable<number[]> = null) {
let ctx = this.ctx;
if (dash != null) {
ctx.lineCap = 'square';
ctx.setLineDash(dash);
this.lineDash = true;
} else if (this.lineDash) {
ctx.lineCap = 'round';
ctx.setLineDash([]);
}
ctx.beginPath();
}
private stroke() {
this.ctx.stroke();
}
private moveTo(x: number, y: number, snap=false) {
x = this.xScale * (x - this.xStart);
y = this.yScale * (y - this.yStart);
if (snap) {
x = Math.round(x);
y = Math.round(y);
}
this.ctx.moveTo(x, y);
}
private lineTo(x: number, y: number, snap=false) {
x = this.xScale * (x - this.xStart);
y = this.yScale * (y - this.yStart);
if (snap) {
x = Math.round(x);
y = Math.round(y);
}
this.ctx.lineTo(x, y);
}
private updateScale() {
let canvas = this.ctx.canvas;
let w = canvas.width - this.marginLeft - this.marginRight;
let h = canvas.height - this.marginTop - this.marginBottom;
this.xScale = w / (this.xEnd - this.xStart);
this.yScale = h / (this.yEnd - this.yStart);
}
private calculateTickPoints(start: number, end: number) {
// Calculate the spacing of the ticks.
let x = Math.abs(end - start);
let spacing = 1;
if (x >= 1) {
let scale = Math.pow(10, Math.max(0, Math.floor(Math.log10(x) - 1)));
let top2 = Math.floor(x / scale);
if (top2 <= 10) {
spacing = 1;
} else if (top2 <= 20) {
spacing = 2;
} else if (top2 <= 50) {
spacing = 5;
} else {
spacing = 10;
}
spacing *= scale;
}
// Build the array of tick points.
let min = Math.min(start, end);
let max = Math.max(start, end);
let positive: number[] = [];
let negative: number[] = [];
if (min <= 0 && max >= 0) {
positive.push(0);
}
for (let x = spacing; x <= max; x += spacing) {
positive.push(x);
}
for (let x = -spacing; x >= min; x -= spacing) {
negative.push(x);
}
negative.reverse();
return negative.concat(positive);
}
}
export {Graph}