415 lines
15 KiB
TypeScript
415 lines
15 KiB
TypeScript
/**
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* Copyright (c) 2017 The xterm.js authors. All rights reserved.
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* @license MIT
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*/
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import { ICharAtlasConfig } from './Types';
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import { DIM_OPACITY } from 'browser/renderer/atlas/Constants';
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import { IRasterizedGlyph, IBoundingBox, IRasterizedGlyphSet } from '../Types';
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import { DEFAULT_COLOR, DEFAULT_ATTR, FgFlags, Attributes, BgFlags } from 'common/buffer/Constants';
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import { is256Color } from './CharAtlasUtils';
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import { throwIfFalsy } from '../WebglUtils';
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import { IColor } from 'browser/Types';
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import { FLAGS } from '../Constants';
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import { IDisposable } from 'xterm';
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// In practice we're probably never going to exhaust a texture this large. For debugging purposes,
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// however, it can be useful to set this to a really tiny value, to verify that LRU eviction works.
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const TEXTURE_WIDTH = 1024;
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const TEXTURE_HEIGHT = 1024;
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/**
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* The amount of the texture to be filled before throwing it away and starting
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* again. Since the throw away and individual glyph draws don't cost too much,
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* this prevent juggling multiple textures in the GL context.
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*/
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const TEXTURE_CAPACITY = Math.floor(TEXTURE_HEIGHT * 0.8);
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const TRANSPARENT_COLOR = {
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css: 'rgba(0, 0, 0, 0)',
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rgba: 0
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};
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/**
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* A shared object which is used to draw nothing for a particular cell.
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*/
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const NULL_RASTERIZED_GLYPH: IRasterizedGlyph = {
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offset: { x: 0, y: 0 },
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texturePosition: { x: 0, y: 0 },
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texturePositionClipSpace: { x: 0, y: 0 },
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size: { x: 0, y: 0 },
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sizeClipSpace: { x: 0, y: 0 }
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};
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const TMP_CANVAS_GLYPH_PADDING = 2;
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export class WebglCharAtlas implements IDisposable {
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private _didWarmUp: boolean = false;
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private _cacheMap: { [code: number]: IRasterizedGlyphSet } = {};
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private _cacheMapCombined: { [chars: string]: IRasterizedGlyphSet } = {};
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// The texture that the atlas is drawn to
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public cacheCanvas: HTMLCanvasElement;
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private _cacheCtx: CanvasRenderingContext2D;
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private _tmpCanvas: HTMLCanvasElement;
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// A temporary context that glyphs are drawn to before being transfered to the atlas.
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private _tmpCtx: CanvasRenderingContext2D;
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// Since glyphs are expected to be around the same height, the packing
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// strategy used it to fill a row with glyphs while keeping track of the
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// tallest glyph in the row. Once the row is full a new row is started at
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// (0,lastRow+lastRowTallestGlyph).
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private _currentRowY: number = 0;
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private _currentRowX: number = 0;
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private _currentRowHeight: number = 0;
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public hasCanvasChanged = false;
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private _workBoundingBox: IBoundingBox = { top: 0, left: 0, bottom: 0, right: 0 };
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constructor(document: Document, private _config: ICharAtlasConfig) {
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this.cacheCanvas = document.createElement('canvas');
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this.cacheCanvas.width = TEXTURE_WIDTH;
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this.cacheCanvas.height = TEXTURE_HEIGHT;
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// The canvas needs alpha because we use clearColor to convert the background color to alpha.
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// It might also contain some characters with transparent backgrounds if allowTransparency is
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// set.
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this._cacheCtx = throwIfFalsy(this.cacheCanvas.getContext('2d', {alpha: true}));
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this._tmpCanvas = document.createElement('canvas');
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this._tmpCanvas.width = this._config.scaledCharWidth * 2 + TMP_CANVAS_GLYPH_PADDING * 2;
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this._tmpCanvas.height = this._config.scaledCharHeight + TMP_CANVAS_GLYPH_PADDING * 2;
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this._tmpCtx = throwIfFalsy(this._tmpCanvas.getContext('2d', {alpha: this._config.allowTransparency}));
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// This is useful for debugging
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document.body.appendChild(this.cacheCanvas);
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}
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public dispose(): void {
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if (this.cacheCanvas.parentElement) {
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this.cacheCanvas.parentElement.removeChild(this.cacheCanvas);
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}
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}
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public warmUp(): void {
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if (!this._didWarmUp) {
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this._doWarmUp();
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this._didWarmUp = true;
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}
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}
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protected _doWarmUp(): void {
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// Pre-fill with ASCII 33-126
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for (let i = 33; i < 126; i++) {
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const rasterizedGlyph = this._drawToCache(i, DEFAULT_COLOR, DEFAULT_COLOR);
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this._cacheMap[i] = {
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[DEFAULT_COLOR]: {
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[DEFAULT_COLOR]: rasterizedGlyph
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}
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};
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}
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}
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public beginFrame(): boolean {
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if (this._currentRowY > TEXTURE_CAPACITY) {
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this._cacheCtx.clearRect(0, 0, TEXTURE_WIDTH, TEXTURE_HEIGHT);
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this._cacheMap = {};
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this._currentRowHeight = 0;
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this._currentRowX = 0;
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this._currentRowY = 0;
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this._doWarmUp();
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return true;
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}
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return false;
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}
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public getRasterizedGlyphCombinedChar(chars: string, bg: number, fg: number): IRasterizedGlyph {
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let rasterizedGlyphSet = this._cacheMapCombined[chars];
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if (!rasterizedGlyphSet) {
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rasterizedGlyphSet = {};
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this._cacheMapCombined[chars] = rasterizedGlyphSet;
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}
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let rasterizedGlyph: IRasterizedGlyph | undefined;
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const rasterizedGlyphSetBg = rasterizedGlyphSet[bg];
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if (rasterizedGlyphSetBg) {
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rasterizedGlyph = rasterizedGlyphSetBg[fg];
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}
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if (!rasterizedGlyph) {
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rasterizedGlyph = this._drawToCache(chars, bg, fg);
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if (!rasterizedGlyphSet[bg]) {
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rasterizedGlyphSet[bg] = {};
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}
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rasterizedGlyphSet[bg]![fg] = rasterizedGlyph;
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}
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return rasterizedGlyph;
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}
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/**
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* Gets the glyphs texture coords, drawing the texture if it's not already
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*/
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public getRasterizedGlyph(code: number, bg: number, fg: number): IRasterizedGlyph {
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let rasterizedGlyphSet = this._cacheMap[code];
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if (!rasterizedGlyphSet) {
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rasterizedGlyphSet = {};
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this._cacheMap[code] = rasterizedGlyphSet;
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}
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let rasterizedGlyph: IRasterizedGlyph | undefined;
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const rasterizedGlyphSetBg = rasterizedGlyphSet[bg];
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if (rasterizedGlyphSetBg) {
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rasterizedGlyph = rasterizedGlyphSetBg[fg];
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}
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if (!rasterizedGlyph) {
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rasterizedGlyph = this._drawToCache(code, bg, fg);
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if (!rasterizedGlyphSet[bg]) {
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rasterizedGlyphSet[bg] = {};
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}
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rasterizedGlyphSet[bg]![fg] = rasterizedGlyph;
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}
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return rasterizedGlyph;
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}
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private _getColorFromAnsiIndex(idx: number): IColor {
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if (idx >= this._config.colors.ansi.length) {
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throw new Error('No color found for idx ' + idx);
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}
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return this._config.colors.ansi[idx];
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}
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private _getBackgroundColor(bg: number, fg: number): IColor {
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if (this._config.allowTransparency) {
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// The background color might have some transparency, so we need to render it as fully
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// transparent in the atlas. Otherwise we'd end up drawing the transparent background twice
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// around the anti-aliased edges of the glyph, and it would look too dark.
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return TRANSPARENT_COLOR;
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} else if (fg & FgFlags.INVERSE) {
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return this._config.colors.foreground;
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} else if (is256Color(bg)) {
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return this._getColorFromAnsiIndex(bg & Attributes.PCOLOR_MASK);
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}
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// TODO: Support true color
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return this._config.colors.background;
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}
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private _getForegroundColor(fg: number): IColor {
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if (fg & FgFlags.INVERSE) {
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return this._config.colors.background;
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} else if (is256Color(fg)) {
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return this._getColorFromAnsiIndex(fg & Attributes.PCOLOR_MASK);
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}
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// TODO: Support true color
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return this._config.colors.foreground;
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}
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private _drawToCache(code: number, bg: number, fg: number): IRasterizedGlyph;
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private _drawToCache(chars: string, bg: number, fg: number): IRasterizedGlyph;
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private _drawToCache(codeOrChars: number | string, bg: number, fg: number): IRasterizedGlyph {
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const chars = typeof codeOrChars === 'number' ? String.fromCharCode(codeOrChars) : codeOrChars;
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this.hasCanvasChanged = true;
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const bold = !!(fg & FgFlags.BOLD);
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const dim = !!(bg & BgFlags.DIM);
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const italic = !!(bg & BgFlags.ITALIC);
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this._tmpCtx.save();
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// draw the background
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const backgroundColor = this._getBackgroundColor(bg, fg);
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// Use a 'copy' composite operation to clear any existing glyph out of _tmpCtxWithAlpha, regardless of
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// transparency in backgroundColor
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this._tmpCtx.globalCompositeOperation = 'copy';
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this._tmpCtx.fillStyle = backgroundColor.css;
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this._tmpCtx.fillRect(0, 0, this._tmpCanvas.width, this._tmpCanvas.height);
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this._tmpCtx.globalCompositeOperation = 'source-over';
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// draw the foreground/glyph
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const fontWeight = bold ? this._config.fontWeightBold : this._config.fontWeight;
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const fontStyle = italic ? 'italic' : '';
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this._tmpCtx.font =
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`${fontStyle} ${fontWeight} ${this._config.fontSize * this._config.devicePixelRatio}px ${this._config.fontFamily}`;
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this._tmpCtx.textBaseline = 'top';
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this._tmpCtx.fillStyle = this._getForegroundColor(fg).css;
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// Apply alpha to dim the character
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if (dim) {
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this._tmpCtx.globalAlpha = DIM_OPACITY;
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}
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// Draw the character
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this._tmpCtx.fillText(chars, TMP_CANVAS_GLYPH_PADDING, TMP_CANVAS_GLYPH_PADDING);
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this._tmpCtx.restore();
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// clear the background from the character to avoid issues with drawing over the previous
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// character if it extends past it's bounds
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const imageData = this._tmpCtx.getImageData(
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0, 0, this._tmpCanvas.width, this._tmpCanvas.height
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);
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// TODO: Support transparency
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// let isEmpty = false;
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// if (!this._config.allowTransparency) {
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// isEmpty = clearColor(imageData, backgroundColor);
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// }
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// Clear out the background color and determine if the glyph is empty.
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const isEmpty = clearColor(imageData, backgroundColor);
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// Handle empty glyphs
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if (isEmpty) {
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return NULL_RASTERIZED_GLYPH;
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}
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const rasterizedGlyph = this._findGlyphBoundingBox(imageData, this._workBoundingBox);
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const clippedImageData = this._clipImageData(imageData, this._workBoundingBox);
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// Check if there is enough room in the current row and go to next if needed
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if (this._currentRowX + this._config.scaledCharWidth > TEXTURE_WIDTH) {
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this._currentRowX = 0;
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this._currentRowY += this._currentRowHeight;
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this._currentRowHeight = 0;
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}
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// Record texture position
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rasterizedGlyph.texturePosition.x = this._currentRowX;
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rasterizedGlyph.texturePosition.y = this._currentRowY;
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rasterizedGlyph.texturePositionClipSpace.x = this._currentRowX / TEXTURE_WIDTH;
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rasterizedGlyph.texturePositionClipSpace.y = this._currentRowY / TEXTURE_HEIGHT;
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// Update atlas current row
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this._currentRowHeight = Math.max(this._currentRowHeight, rasterizedGlyph.size.y);
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this._currentRowX += rasterizedGlyph.size.x;
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// putImageData doesn't do any blending, so it will overwrite any existing cache entry for us
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this._cacheCtx.putImageData(clippedImageData, rasterizedGlyph.texturePosition.x, rasterizedGlyph.texturePosition.y);
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return rasterizedGlyph;
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}
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/**
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* Given an ImageData object, find the bounding box of the non-transparent
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* portion of the texture and return an IRasterizedGlyph with these
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* dimensions.
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* @param imageData The image data to read.
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* @param boundingBox An IBoundingBox to put the clipped bounding box values.
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*/
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private _findGlyphBoundingBox(imageData: ImageData, boundingBox: IBoundingBox): IRasterizedGlyph {
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boundingBox.top = 0;
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let found = false;
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for (let y = 0; y < this._tmpCanvas.height; y++) {
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for (let x = 0; x < this._tmpCanvas.width; x++) {
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const alphaOffset = y * this._tmpCanvas.width * 4 + x * 4 + 3;
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if (imageData.data[alphaOffset] !== 0) {
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boundingBox.top = y;
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found = true;
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break;
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}
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}
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if (found) {
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break;
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}
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}
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boundingBox.left = 0;
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found = false;
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for (let x = 0; x < this._tmpCanvas.width; x++) {
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for (let y = 0; y < this._tmpCanvas.height; y++) {
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const alphaOffset = y * this._tmpCanvas.width * 4 + x * 4 + 3;
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if (imageData.data[alphaOffset] !== 0) {
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boundingBox.left = x;
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found = true;
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break;
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}
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}
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if (found) {
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break;
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}
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}
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boundingBox.right = this._tmpCanvas.width;
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found = false;
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for (let x = this._tmpCanvas.width - 1; x >= 0; x--) {
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for (let y = 0; y < this._tmpCanvas.height; y++) {
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const alphaOffset = y * this._tmpCanvas.width * 4 + x * 4 + 3;
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if (imageData.data[alphaOffset] !== 0) {
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boundingBox.right = x;
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found = true;
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break;
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}
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}
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if (found) {
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break;
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}
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}
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boundingBox.bottom = this._tmpCanvas.height;
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found = false;
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for (let y = this._tmpCanvas.height - 1; y >= 0; y--) {
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for (let x = 0; x < this._tmpCanvas.width; x++) {
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const alphaOffset = y * this._tmpCanvas.width * 4 + x * 4 + 3;
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if (imageData.data[alphaOffset] !== 0) {
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boundingBox.bottom = y;
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found = true;
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break;
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}
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}
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if (found) {
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break;
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}
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}
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return {
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texturePosition: { x: 0, y: 0 },
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texturePositionClipSpace: { x: 0, y: 0 },
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size: {
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x: boundingBox.right - boundingBox.left + 1,
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y: boundingBox.bottom - boundingBox.top + 1
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},
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sizeClipSpace: {
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x: (boundingBox.right - boundingBox.left + 1) / TEXTURE_WIDTH,
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y: (boundingBox.bottom - boundingBox.top + 1) / TEXTURE_HEIGHT
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},
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offset: {
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x: -boundingBox.left + TMP_CANVAS_GLYPH_PADDING,
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y: -boundingBox.top + TMP_CANVAS_GLYPH_PADDING
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}
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};
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}
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private _clipImageData(imageData: ImageData, boundingBox: IBoundingBox): ImageData {
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const width = boundingBox.right - boundingBox.left + 1;
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const height = boundingBox.bottom - boundingBox.top + 1;
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const clippedData = new Uint8ClampedArray(width * height * 4);
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for (let y = boundingBox.top; y <= boundingBox.bottom; y++) {
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for (let x = boundingBox.left; x <= boundingBox.right; x++) {
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const oldOffset = y * this._tmpCanvas.width * 4 + x * 4;
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const newOffset = (y - boundingBox.top) * width * 4 + (x - boundingBox.left) * 4;
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clippedData[newOffset] = imageData.data[oldOffset];
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clippedData[newOffset + 1] = imageData.data[oldOffset + 1];
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clippedData[newOffset + 2] = imageData.data[oldOffset + 2];
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clippedData[newOffset + 3] = imageData.data[oldOffset + 3];
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}
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}
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return new ImageData(clippedData, width, height);
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}
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}
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/**
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* Makes a partiicular rgb color in an ImageData completely transparent.
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* @returns True if the result is "empty", meaning all pixels are fully transparent.
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*/
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function clearColor(imageData: ImageData, color: IColor): boolean {
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let isEmpty = true;
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const r = color.rgba >>> 24;
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const g = color.rgba >>> 16 & 0xFF;
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const b = color.rgba >>> 8 & 0xFF;
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for (let offset = 0; offset < imageData.data.length; offset += 4) {
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if (imageData.data[offset] === r &&
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imageData.data[offset + 1] === g &&
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imageData.data[offset + 2] === b) {
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imageData.data[offset + 3] = 0;
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} else {
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isEmpty = false;
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}
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}
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return isEmpty;
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}
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