Merge remote-tracking branch 'ups/master' into pr/1148

src/shared/CharAtlasGenerator.ts

@@ -0,0 +1,141 @@
+/**
+ * Copyright (c) 2018 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { isFirefox } from './utils/Browser';
+import { FontWeight } from './Types';
+
+declare const Promise: any;
+
+export interface IOffscreenCanvas {
+  width: number;
+  height: number;
+  getContext(type: '2d', config?: Canvas2DContextAttributes): CanvasRenderingContext2D;
+  transferToImageBitmap(): ImageBitmap;
+}
+
+export interface ICharAtlasRequest {
+  scaledCharWidth: number;
+  scaledCharHeight: number;
+  fontSize: number;
+  fontFamily: string;
+  fontWeight: FontWeight;
+  fontWeightBold: FontWeight;
+  background: string;
+  foreground: string;
+  ansiColors: string[];
+  devicePixelRatio: number;
+  allowTransparency: boolean;
+}
+
+export const CHAR_ATLAS_CELL_SPACING = 1;
+
+/**
+ * Generates a char atlas.
+ * @param context The window or worker context.
+ * @param canvasFactory A function to generate a canvas with a width or height.
+ * @param request The config for the new char atlas.
+ */
+export function generateCharAtlas(context: Window, canvasFactory: (width: number, height: number) => HTMLCanvasElement | IOffscreenCanvas, request: ICharAtlasRequest): HTMLCanvasElement | Promise<ImageBitmap> {
+  const cellWidth = request.scaledCharWidth + CHAR_ATLAS_CELL_SPACING;
+  const cellHeight = request.scaledCharHeight + CHAR_ATLAS_CELL_SPACING;
+  const canvas = canvasFactory(
+    /*255 ascii chars*/255 * cellWidth,
+    (/*default+default bold*/2 + /*0-15*/16) * cellHeight
+  );
+  const ctx = canvas.getContext('2d', {alpha: request.allowTransparency});
+
+  ctx.fillStyle = request.background;
+  ctx.fillRect(0, 0, canvas.width, canvas.height);
+
+  ctx.save();
+  ctx.fillStyle = request.foreground;
+  ctx.font = getFont(request.fontWeight, request);
+  ctx.textBaseline = 'top';
+
+  // Default color
+  for (let i = 0; i < 256; i++) {
+    ctx.save();
+    ctx.beginPath();
+    ctx.rect(i * cellWidth, 0, cellWidth, cellHeight);
+    ctx.clip();
+    ctx.fillText(String.fromCharCode(i), i * cellWidth, 0);
+    ctx.restore();
+  }
+  // Default color bold
+  ctx.save();
+  ctx.font = getFont(request.fontWeightBold, request);
+  for (let i = 0; i < 256; i++) {
+    ctx.save();
+    ctx.beginPath();
+    ctx.rect(i * cellWidth, cellHeight, cellWidth, cellHeight);
+    ctx.clip();
+    ctx.fillText(String.fromCharCode(i), i * cellWidth, cellHeight);
+    ctx.restore();
+  }
+  ctx.restore();
+
+  // Colors 0-15
+  ctx.font = getFont(request.fontWeight, request);
+  for (let colorIndex = 0; colorIndex < 16; colorIndex++) {
+    // colors 8-15 are bold
+    if (colorIndex === 8) {
+      ctx.font = getFont(request.fontWeightBold, request);
+    }
+    const y = (colorIndex + 2) * cellHeight;
+    // Draw ascii characters
+    for (let i = 0; i < 256; i++) {
+      ctx.save();
+      ctx.beginPath();
+      ctx.rect(i * cellWidth, y, cellWidth, cellHeight);
+      ctx.clip();
+      ctx.fillStyle = request.ansiColors[colorIndex];
+      ctx.fillText(String.fromCharCode(i), i * cellWidth, y);
+      ctx.restore();
+    }
+  }
+  ctx.restore();
+
+  // Support is patchy for createImageBitmap at the moment, pass a canvas back
+  // if support is lacking as drawImage works there too. Firefox is also
+  // included here as ImageBitmap appears both buggy and has horrible
+  // performance (tested on v55).
+  if (!('createImageBitmap' in context) || isFirefox) {
+    // Don't attempt to clear background colors if createImageBitmap is not supported
+    if (canvas instanceof HTMLCanvasElement) {
+      // Just return the HTMLCanvas if it's a HTMLCanvasElement
+      return canvas;
+    } else {
+      // Transfer to an ImageBitmap is this is an OffscreenCanvas
+      return new Promise(r => r(canvas.transferToImageBitmap()));
+    }
+  }
+
+  const charAtlasImageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
+
+  // Remove the background color from the image so characters may overlap
+  const r = parseInt(request.background.substr(1, 2), 16);
+  const g = parseInt(request.background.substr(3, 2), 16);
+  const b = parseInt(request.background.substr(5, 2), 16);
+  clearColor(charAtlasImageData, r, g, b);
+
+  return context.createImageBitmap(charAtlasImageData);
+}
+
+/**
+ * Makes a partiicular rgb color in an ImageData completely transparent.
+ */
+function clearColor(imageData: ImageData, r: number, g: number, b: number): void {
+  for (let offset = 0; offset < imageData.data.length; offset += 4) {
+    if (imageData.data[offset] === r &&
+        imageData.data[offset + 1] === g &&
+        imageData.data[offset + 2] === b) {
+      imageData.data[offset + 3] = 0;
+    }
+  }
+}
+
+function getFont(fontWeight: FontWeight, request: ICharAtlasRequest): string {
+  return `${fontWeight} ${request.fontSize * request.devicePixelRatio}px ${request.fontFamily}`;
+}

src/shared/Types.ts

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+/**
+ * Copyright (c) 2018 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+ export type FontWeight = 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900';

src/shared/utils/Browser.ts

@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) 2016 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+const isNode = (typeof navigator === 'undefined') ? true : false;
+const userAgent = (isNode) ? 'node' : navigator.userAgent;
+const platform = (isNode) ? 'node' : navigator.platform;
+
+export const isFirefox = !!~userAgent.indexOf('Firefox');
+export const isMSIE = !!~userAgent.indexOf('MSIE') || !!~userAgent.indexOf('Trident');
+
+// Find the users platform. We use this to interpret the meta key
+// and ISO third level shifts.
+// http://stackoverflow.com/q/19877924/577598
+export const isMac = contains(['Macintosh', 'MacIntel', 'MacPPC', 'Mac68K'], platform);
+export const isIpad = platform === 'iPad';
+export const isIphone = platform === 'iPhone';
+export const isMSWindows = contains(['Windows', 'Win16', 'Win32', 'WinCE'], platform);
+export const isLinux = platform.indexOf('Linux') >= 0;
+
+/**
+ * Return if the given array contains the given element
+ * @param {Array} array The array to search for the given element.
+ * @param {Object} el The element to look for into the array
+ */
+export function contains(arr: any[], el: any): boolean {
+  return arr.indexOf(el) >= 0;
+};