Benjamin Woodruff
3971fc9b4e
Drawing dim colors sets the globalAlpha to 0.5, so we need to save/restore the ctx state. Otherwise, every time we draw some dim content, our display will get progressively dimmer. I tested this by running `echo '\u001b[2mfoo'` a few times in zsh. Fixes #1424
355 lines
13 KiB
TypeScript
355 lines
13 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 { IRenderLayer, IColorSet, IRenderDimensions } from './Types';
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import { CharData, ITerminal } from '../Types';
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import { DIM_OPACITY, INVERTED_DEFAULT_COLOR } from './atlas/Types';
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import { CHAR_ATLAS_CELL_SPACING } from '../shared/atlas/Types';
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import { acquireCharAtlas } from './atlas/CharAtlas';
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import { CHAR_DATA_CHAR_INDEX } from '../Buffer';
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export abstract class BaseRenderLayer implements IRenderLayer {
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private _canvas: HTMLCanvasElement;
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protected _ctx: CanvasRenderingContext2D;
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private _scaledCharWidth: number = 0;
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private _scaledCharHeight: number = 0;
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private _scaledCellWidth: number = 0;
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private _scaledCellHeight: number = 0;
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private _scaledCharLeft: number = 0;
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private _scaledCharTop: number = 0;
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private _charAtlas: HTMLCanvasElement | ImageBitmap;
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constructor(
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private _container: HTMLElement,
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id: string,
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zIndex: number,
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private _alpha: boolean,
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protected _colors: IColorSet
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) {
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this._canvas = document.createElement('canvas');
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this._canvas.classList.add(`xterm-${id}-layer`);
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this._canvas.style.zIndex = zIndex.toString();
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this._initCanvas();
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this._container.appendChild(this._canvas);
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}
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private _initCanvas(): void {
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this._ctx = this._canvas.getContext('2d', {alpha: this._alpha});
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// Draw the background if this is an opaque layer
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if (!this._alpha) {
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this.clearAll();
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}
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}
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public onOptionsChanged(terminal: ITerminal): void {}
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public onBlur(terminal: ITerminal): void {}
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public onFocus(terminal: ITerminal): void {}
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public onCursorMove(terminal: ITerminal): void {}
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public onGridChanged(terminal: ITerminal, startRow: number, endRow: number): void {}
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public onSelectionChanged(terminal: ITerminal, start: [number, number], end: [number, number]): void {}
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public onThemeChanged(terminal: ITerminal, colorSet: IColorSet): void {
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this._refreshCharAtlas(terminal, colorSet);
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}
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protected setTransparency(terminal: ITerminal, alpha: boolean): void {
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// Do nothing when alpha doesn't change
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if (alpha === this._alpha) {
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return;
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}
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// Create new canvas and replace old one
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const oldCanvas = this._canvas;
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this._alpha = alpha;
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// Cloning preserves properties
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this._canvas = <HTMLCanvasElement>this._canvas.cloneNode();
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this._initCanvas();
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this._container.replaceChild(this._canvas, oldCanvas);
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// Regenerate char atlas and force a full redraw
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this._refreshCharAtlas(terminal, this._colors);
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this.onGridChanged(terminal, 0, terminal.rows - 1);
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}
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/**
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* Refreshes the char atlas, aquiring a new one if necessary.
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* @param terminal The terminal.
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* @param colorSet The color set to use for the char atlas.
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*/
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private _refreshCharAtlas(terminal: ITerminal, colorSet: IColorSet): void {
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if (this._scaledCharWidth <= 0 && this._scaledCharHeight <= 0) {
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return;
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}
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this._charAtlas = null;
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const result = acquireCharAtlas(terminal, colorSet, this._scaledCharWidth, this._scaledCharHeight);
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if (result instanceof HTMLCanvasElement) {
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this._charAtlas = result;
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} else {
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result.then(bitmap => this._charAtlas = bitmap);
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}
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}
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public resize(terminal: ITerminal, dim: IRenderDimensions): void {
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this._scaledCellWidth = dim.scaledCellWidth;
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this._scaledCellHeight = dim.scaledCellHeight;
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this._scaledCharWidth = dim.scaledCharWidth;
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this._scaledCharHeight = dim.scaledCharHeight;
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this._scaledCharLeft = dim.scaledCharLeft;
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this._scaledCharTop = dim.scaledCharTop;
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this._canvas.width = dim.scaledCanvasWidth;
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this._canvas.height = dim.scaledCanvasHeight;
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this._canvas.style.width = `${dim.canvasWidth}px`;
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this._canvas.style.height = `${dim.canvasHeight}px`;
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// Draw the background if this is an opaque layer
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if (!this._alpha) {
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this.clearAll();
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}
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this._refreshCharAtlas(terminal, this._colors);
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}
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public abstract reset(terminal: ITerminal): void;
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/**
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* Fills 1+ cells completely. This uses the existing fillStyle on the context.
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* @param x The column to start at.
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* @param y The row to start at
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* @param width The number of columns to fill.
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* @param height The number of rows to fill.
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*/
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protected fillCells(x: number, y: number, width: number, height: number): void {
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this._ctx.fillRect(
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x * this._scaledCellWidth,
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y * this._scaledCellHeight,
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width * this._scaledCellWidth,
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height * this._scaledCellHeight);
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}
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/**
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* Fills a 1px line (2px on HDPI) at the bottom of the cell. This uses the
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* existing fillStyle on the context.
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* @param x The column to fill.
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* @param y The row to fill.
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*/
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protected fillBottomLineAtCells(x: number, y: number, width: number = 1): void {
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this._ctx.fillRect(
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x * this._scaledCellWidth,
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(y + 1) * this._scaledCellHeight - window.devicePixelRatio - 1 /* Ensure it's drawn within the cell */,
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width * this._scaledCellWidth,
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window.devicePixelRatio);
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}
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/**
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* Fills a 1px line (2px on HDPI) at the left of the cell. This uses the
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* existing fillStyle on the context.
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* @param x The column to fill.
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* @param y The row to fill.
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*/
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protected fillLeftLineAtCell(x: number, y: number): void {
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this._ctx.fillRect(
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x * this._scaledCellWidth,
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y * this._scaledCellHeight,
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window.devicePixelRatio,
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this._scaledCellHeight);
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}
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/**
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* Strokes a 1px rectangle (2px on HDPI) around a cell. This uses the existing
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* strokeStyle on the context.
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* @param x The column to fill.
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* @param y The row to fill.
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*/
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protected strokeRectAtCell(x: number, y: number, width: number, height: number): void {
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this._ctx.lineWidth = window.devicePixelRatio;
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this._ctx.strokeRect(
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x * this._scaledCellWidth + window.devicePixelRatio / 2,
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y * this._scaledCellHeight + (window.devicePixelRatio / 2),
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width * this._scaledCellWidth - window.devicePixelRatio,
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(height * this._scaledCellHeight) - window.devicePixelRatio);
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}
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/**
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* Clears the entire canvas.
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*/
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protected clearAll(): void {
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if (this._alpha) {
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this._ctx.clearRect(0, 0, this._canvas.width, this._canvas.height);
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} else {
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this._ctx.fillStyle = this._colors.background.css;
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this._ctx.fillRect(0, 0, this._canvas.width, this._canvas.height);
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}
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}
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/**
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* Clears 1+ cells completely.
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* @param x The column to start at.
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* @param y The row to start at.
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* @param width The number of columns to clear.
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* @param height The number of rows to clear.
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*/
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protected clearCells(x: number, y: number, width: number, height: number): void {
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if (this._alpha) {
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this._ctx.clearRect(
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x * this._scaledCellWidth,
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y * this._scaledCellHeight,
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width * this._scaledCellWidth,
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height * this._scaledCellHeight);
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} else {
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this._ctx.fillStyle = this._colors.background.css;
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this._ctx.fillRect(
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x * this._scaledCellWidth,
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y * this._scaledCellHeight,
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width * this._scaledCellWidth,
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height * this._scaledCellHeight);
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}
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}
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/**
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* Draws a truecolor character at the cell. The character will be clipped to
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* ensure that it fits with the cell, including the cell to the right if it's
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* a wide character. This uses the existing fillStyle on the context.
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* @param terminal The terminal.
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* @param charData The char data for the character to draw.
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* @param x The column to draw at.
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* @param y The row to draw at.
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* @param color The color of the character.
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*/
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protected fillCharTrueColor(terminal: ITerminal, charData: CharData, x: number, y: number): void {
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this._ctx.font = this._getFont(terminal, false, false);
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this._ctx.textBaseline = 'top';
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this._clipRow(terminal, y);
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this._ctx.fillText(
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charData[CHAR_DATA_CHAR_INDEX],
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x * this._scaledCellWidth + this._scaledCharLeft,
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y * this._scaledCellHeight + this._scaledCharTop);
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}
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/**
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* Draws a character at a cell. If possible this will draw using the character
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* atlas to reduce draw time.
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* @param terminal The terminal.
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* @param char The character.
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* @param code The character code.
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* @param width The width of the character.
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* @param x The column to draw at.
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* @param y The row to draw at.
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* @param fg The foreground color, in the format stored within the attributes.
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* @param bg The background color, in the format stored within the attributes.
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* This is used to validate whether a cached image can be used.
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* @param bold Whether the text is bold.
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*/
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protected drawChar(terminal: ITerminal, char: string, code: number, width: number, x: number, y: number, fg: number, bg: number, bold: boolean, dim: boolean, italic: boolean): void {
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const isAscii = code < 256;
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// A color is basic if it is one of the 4 bit ANSI colors.
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const isBasicColor = fg < 16;
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const isDefaultColor = fg >= 256;
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const isDefaultBackground = bg >= 256;
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const drawInBrightColor = (terminal.options.drawBoldTextInBrightColors && bold && fg < 8);
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if (this._charAtlas && isAscii && (isBasicColor || isDefaultColor) && isDefaultBackground && !italic) {
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this._ctx.save(); // we may set globalAlpha, so we need to be able to restore
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let colorIndex: number;
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if (isDefaultColor) {
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colorIndex = (bold && terminal.options.enableBold ? 1 : 0);
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} else {
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colorIndex = 2 + fg + (bold && terminal.options.enableBold ? 16 : 0) + (drawInBrightColor ? 8 : 0);
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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._scaledCharWidth + CHAR_ATLAS_CELL_SPACING;
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const charAtlasCellHeight = this._scaledCharHeight + CHAR_ATLAS_CELL_SPACING;
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// Apply alpha to dim the character
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if (dim) {
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this._ctx.globalAlpha = DIM_OPACITY;
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}
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this._ctx.drawImage(this._charAtlas,
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code * charAtlasCellWidth,
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colorIndex * charAtlasCellHeight,
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charAtlasCellWidth,
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this._scaledCharHeight,
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x * this._scaledCellWidth + this._scaledCharLeft,
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y * this._scaledCellHeight + this._scaledCharTop,
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charAtlasCellWidth,
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this._scaledCharHeight);
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this._ctx.restore();
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} else {
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this._drawUncachedChar(terminal, char, width, fg + (drawInBrightColor ? 8 : 0), x, y, bold && terminal.options.enableBold, dim, italic);
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}
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// This draws the atlas (for debugging purposes)
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// this._ctx.clearRect(0, 0, this._canvas.width, this._canvas.height);
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// this._ctx.drawImage(this._charAtlas, 0, 0);
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}
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/**
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* Draws a character at a cell. The character will be clipped to
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* ensure that it fits with the cell, including the cell to the right if it's
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* a wide character.
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* @param terminal The terminal.
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* @param char The character.
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* @param width The width of the character.
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* @param fg The foreground color, in the format stored within the attributes.
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* @param x The column to draw at.
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* @param y The row to draw at.
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*/
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private _drawUncachedChar(terminal: ITerminal, char: string, width: number, fg: number, x: number, y: number, bold: boolean, dim: boolean, italic: boolean): void {
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this._ctx.save();
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this._ctx.font = this._getFont(terminal, bold, italic);
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this._ctx.textBaseline = 'top';
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if (fg === INVERTED_DEFAULT_COLOR) {
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this._ctx.fillStyle = this._colors.background.css;
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} else if (fg < 256) {
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// 256 color support
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this._ctx.fillStyle = this._colors.ansi[fg].css;
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} else {
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this._ctx.fillStyle = this._colors.foreground.css;
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}
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this._clipRow(terminal, y);
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// Apply alpha to dim the character
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if (dim) {
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this._ctx.globalAlpha = DIM_OPACITY;
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}
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// Draw the character
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this._ctx.fillText(
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char,
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x * this._scaledCellWidth + this._scaledCharLeft,
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y * this._scaledCellHeight + this._scaledCharTop);
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this._ctx.restore();
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}
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/**
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* Clips a row to ensure no pixels will be drawn outside the cells in the row.
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* @param terminal The terminal.
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* @param y The row to clip.
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*/
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private _clipRow(terminal: ITerminal, y: number): void {
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this._ctx.beginPath();
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this._ctx.rect(
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0,
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y * this._scaledCellHeight,
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terminal.cols * this._scaledCellWidth,
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this._scaledCellHeight);
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this._ctx.clip();
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}
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/**
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* Gets the current font.
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* @param terminal The terminal.
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* @param isBold If we should use the bold fontWeight.
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*/
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protected _getFont(terminal: ITerminal, isBold: boolean, isItalic: boolean): string {
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const fontWeight = isBold ? terminal.options.fontWeightBold : terminal.options.fontWeight;
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const fontStyle = isItalic ? 'italic' : '';
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return `${fontStyle} ${fontWeight} ${terminal.options.fontSize * window.devicePixelRatio}px ${terminal.options.fontFamily}`;
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}
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}
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