Benjamin Woodruff
6f21385cd8
The API defined by BaseCharAtlas will let us support multiple char atlas implementations at once. I tested this by running the demo with Chrome's profiler, which shows that calls are going to StaticCharAtlas/drawImage instead of _drawUncachedChar. Applications using 256 colors also still work fine, via _drawUncachedChar.
101 lines
3.0 KiB
TypeScript
101 lines
3.0 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 { DIM_OPACITY, IGlyphIdentifier } from './Types';
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import { ICharAtlasConfig } from '../../shared/atlas/Types';
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import { CHAR_ATLAS_CELL_SPACING } from '../../shared/atlas/Types';
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import { generateCharAtlas } from '../../shared/atlas/CharAtlasGenerator';
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import BaseCharAtlas from './BaseCharAtlas';
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export default class StaticCharAtlas extends BaseCharAtlas {
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private _texture: HTMLCanvasElement | ImageBitmap;
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constructor(private _document: Document, private _config: ICharAtlasConfig) {
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super();
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}
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private _canvasFactory = (width: number, height: number) => {
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const canvas = this._document.createElement('canvas');
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canvas.width = width;
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canvas.height = height;
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return canvas;
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}
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public async _doWarmUp(): Promise<void> {
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const result = generateCharAtlas(window, this._canvasFactory, this._config);
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if (result instanceof Promise) {
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this._texture = await result;
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} else {
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this._texture = result;
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}
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}
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private _isCached(glyph: IGlyphIdentifier, colorIndex: number): boolean {
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const isAscii = glyph.char.charCodeAt(0) < 256;
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// A color is basic if it is one of the standard normal or bold weight
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// colors of the characters held in the char atlas. Note that this excludes
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// the normal weight _light_ color characters.
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const isBasicColor = (colorIndex > 1 && glyph.fg < 16) && (glyph.fg < 8 || glyph.bold);
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const isDefaultColor = glyph.fg >= 256;
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const isDefaultBackground = glyph.bg >= 256;
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return isAscii && (isBasicColor || isDefaultColor) && isDefaultBackground;
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}
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public draw(
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ctx: CanvasRenderingContext2D,
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glyph: IGlyphIdentifier,
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x: number,
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y: number,
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): boolean {
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// we're not warmed up yet
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if (this._texture == null) {
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return false;
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}
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let colorIndex = 0;
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if (glyph.fg < 256) {
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colorIndex = glyph.fg + 2;
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} else {
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// If default color and bold
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if (glyph.bold) {
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colorIndex = 1;
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}
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}
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if (!this._isCached(glyph, colorIndex)) {
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return false;
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}
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// ImageBitmap's draw about twice as fast as from a canvas
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const charAtlasCellWidth = this._config.scaledCharWidth + CHAR_ATLAS_CELL_SPACING;
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const charAtlasCellHeight = this._config.scaledCharHeight + CHAR_ATLAS_CELL_SPACING;
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// Apply alpha to dim the character
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if (glyph.dim) {
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ctx.globalAlpha = DIM_OPACITY;
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}
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// Draw the non-bold version of the same color if bold is not enabled
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/*if (glyph.bold && !terminal.options.enableBold) {
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// Ignore default color as it's not touched above
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if (colorIndex > 1) {
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colorIndex -= 8;
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}
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}*/
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ctx.drawImage(
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this._texture,
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glyph.char.charCodeAt(0) * charAtlasCellWidth,
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colorIndex * charAtlasCellHeight,
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charAtlasCellWidth,
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this._config.scaledCharHeight,
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x,
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y,
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charAtlasCellWidth,
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this._config.scaledCharHeight
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);
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return true;
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}
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}
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