@xterm/addon-webgl
Version:
An addon for [xterm.js](https://github.com/xtermjs/xterm.js) that enables a WebGL2-based renderer. This addon requires xterm.js v4+.
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text/typescript
/**
* Copyright (c) 2017 The xterm.js authors. All rights reserved.
* @license MIT
*/
import { ReadonlyColorSet } from 'browser/Types';
import { acquireTextureAtlas } from 'browser/renderer/shared/CharAtlasCache';
import { TEXT_BASELINE } from 'browser/renderer/shared/Constants';
import { throwIfFalsy } from 'browser/renderer/shared/RendererUtils';
import { IRenderDimensions, ITextureAtlas } from 'browser/renderer/shared/Types';
import { ICoreBrowserService, IThemeService } from 'browser/services/Services';
import { Disposable, toDisposable } from 'common/Lifecycle';
import { CellData } from 'common/buffer/CellData';
import { IOptionsService } from 'common/services/Services';
import { Terminal } from '@xterm/xterm';
import { IRenderLayer } from './Types';
export abstract class BaseRenderLayer extends Disposable implements IRenderLayer {
private _canvas: HTMLCanvasElement;
protected _ctx!: CanvasRenderingContext2D;
private _deviceCharWidth: number = 0;
private _deviceCharHeight: number = 0;
private _deviceCellWidth: number = 0;
private _deviceCellHeight: number = 0;
private _deviceCharLeft: number = 0;
private _deviceCharTop: number = 0;
protected _charAtlas: ITextureAtlas | undefined;
constructor(
terminal: Terminal,
private _container: HTMLElement,
id: string,
zIndex: number,
private _alpha: boolean,
protected readonly _coreBrowserService: ICoreBrowserService,
protected readonly _optionsService: IOptionsService,
protected readonly _themeService: IThemeService
) {
super();
this._canvas = this._coreBrowserService.mainDocument.createElement('canvas');
this._canvas.classList.add(`xterm-${id}-layer`);
this._canvas.style.zIndex = zIndex.toString();
this._initCanvas();
this._container.appendChild(this._canvas);
this.register(this._themeService.onChangeColors(e => {
this._refreshCharAtlas(terminal, e);
this.reset(terminal);
}));
this.register(toDisposable(() => {
this._canvas.remove();
}));
}
private _initCanvas(): void {
this._ctx = throwIfFalsy(this._canvas.getContext('2d', { alpha: this._alpha }));
// Draw the background if this is an opaque layer
if (!this._alpha) {
this._clearAll();
}
}
public handleBlur(terminal: Terminal): void {}
public handleFocus(terminal: Terminal): void {}
public handleCursorMove(terminal: Terminal): void {}
public handleGridChanged(terminal: Terminal, startRow: number, endRow: number): void {}
public handleSelectionChanged(terminal: Terminal, start: [number, number] | undefined, end: [number, number] | undefined, columnSelectMode: boolean = false): void {}
protected _setTransparency(terminal: Terminal, alpha: boolean): void {
// Do nothing when alpha doesn't change
if (alpha === this._alpha) {
return;
}
// Create new canvas and replace old one
const oldCanvas = this._canvas;
this._alpha = alpha;
// Cloning preserves properties
this._canvas = this._canvas.cloneNode() as HTMLCanvasElement;
this._initCanvas();
this._container.replaceChild(this._canvas, oldCanvas);
// Regenerate char atlas and force a full redraw
this._refreshCharAtlas(terminal, this._themeService.colors);
this.handleGridChanged(terminal, 0, terminal.rows - 1);
}
/**
* Refreshes the char atlas, aquiring a new one if necessary.
* @param terminal The terminal.
* @param colorSet The color set to use for the char atlas.
*/
private _refreshCharAtlas(terminal: Terminal, colorSet: ReadonlyColorSet): void {
if (this._deviceCharWidth <= 0 && this._deviceCharHeight <= 0) {
return;
}
this._charAtlas = acquireTextureAtlas(terminal, this._optionsService.rawOptions, colorSet, this._deviceCellWidth, this._deviceCellHeight, this._deviceCharWidth, this._deviceCharHeight, this._coreBrowserService.dpr);
this._charAtlas.warmUp();
}
public resize(terminal: Terminal, dim: IRenderDimensions): void {
this._deviceCellWidth = dim.device.cell.width;
this._deviceCellHeight = dim.device.cell.height;
this._deviceCharWidth = dim.device.char.width;
this._deviceCharHeight = dim.device.char.height;
this._deviceCharLeft = dim.device.char.left;
this._deviceCharTop = dim.device.char.top;
this._canvas.width = dim.device.canvas.width;
this._canvas.height = dim.device.canvas.height;
this._canvas.style.width = `${dim.css.canvas.width}px`;
this._canvas.style.height = `${dim.css.canvas.height}px`;
// Draw the background if this is an opaque layer
if (!this._alpha) {
this._clearAll();
}
this._refreshCharAtlas(terminal, this._themeService.colors);
}
public abstract reset(terminal: Terminal): void;
/**
* Fills a 1px line (2px on HDPI) at the bottom of the cell. This uses the
* existing fillStyle on the context.
* @param x The column to fill.
* @param y The row to fill.
*/
protected _fillBottomLineAtCells(x: number, y: number, width: number = 1): void {
this._ctx.fillRect(
x * this._deviceCellWidth,
(y + 1) * this._deviceCellHeight - this._coreBrowserService.dpr - 1 /* Ensure it's drawn within the cell */,
width * this._deviceCellWidth,
this._coreBrowserService.dpr);
}
/**
* Clears the entire canvas.
*/
protected _clearAll(): void {
if (this._alpha) {
this._ctx.clearRect(0, 0, this._canvas.width, this._canvas.height);
} else {
this._ctx.fillStyle = this._themeService.colors.background.css;
this._ctx.fillRect(0, 0, this._canvas.width, this._canvas.height);
}
}
/**
* Clears 1+ cells completely.
* @param x The column to start at.
* @param y The row to start at.
* @param width The number of columns to clear.
* @param height The number of rows to clear.
*/
protected _clearCells(x: number, y: number, width: number, height: number): void {
if (this._alpha) {
this._ctx.clearRect(
x * this._deviceCellWidth,
y * this._deviceCellHeight,
width * this._deviceCellWidth,
height * this._deviceCellHeight);
} else {
this._ctx.fillStyle = this._themeService.colors.background.css;
this._ctx.fillRect(
x * this._deviceCellWidth,
y * this._deviceCellHeight,
width * this._deviceCellWidth,
height * this._deviceCellHeight);
}
}
/**
* Draws a truecolor character at the cell. The character will be clipped to
* ensure that it fits with the cell, including the cell to the right if it's
* a wide character. This uses the existing fillStyle on the context.
* @param terminal The terminal.
* @param cell The cell data for the character to draw.
* @param x The column to draw at.
* @param y The row to draw at.
*/
protected _fillCharTrueColor(terminal: Terminal, cell: CellData, x: number, y: number): void {
this._ctx.font = this._getFont(terminal, false, false);
this._ctx.textBaseline = TEXT_BASELINE;
this._clipCell(x, y, cell.getWidth());
this._ctx.fillText(
cell.getChars(),
x * this._deviceCellWidth + this._deviceCharLeft,
y * this._deviceCellHeight + this._deviceCharTop + this._deviceCharHeight);
}
/**
* Clips a cell to ensure no pixels will be drawn outside of it.
* @param x The column to clip.
* @param y The row to clip.
* @param width The number of columns to clip.
*/
private _clipCell(x: number, y: number, width: number): void {
this._ctx.beginPath();
this._ctx.rect(
x * this._deviceCellWidth,
y * this._deviceCellHeight,
width * this._deviceCellWidth,
this._deviceCellHeight);
this._ctx.clip();
}
/**
* Gets the current font.
* @param terminal The terminal.
* @param isBold If we should use the bold fontWeight.
*/
protected _getFont(terminal: Terminal, isBold: boolean, isItalic: boolean): string {
const fontWeight = isBold ? terminal.options.fontWeightBold : terminal.options.fontWeight;
const fontStyle = isItalic ? 'italic' : '';
return `${fontStyle} ${fontWeight} ${terminal.options.fontSize! * this._coreBrowserService.dpr}px ${terminal.options.fontFamily}`;
}
}