Remove StaticCharAtlas support (fixes #1576)

demo/main.js

@@ -182,7 +182,7 @@ function initOptions(term) {
     bellSound: null,
     bellStyle: ['none', 'sound'],
     cursorStyle: ['block', 'underline', 'bar'],
-    experimentalCharAtlas: ['none', 'static', 'dynamic'],
+    experimentalCharAtlas: ['none', 'dynamic'],
     fontFamily: null,
     fontWeight: ['normal', 'bold', '100', '200', '300', '400', '500', '600', '700', '800', '900'],
     fontWeightBold: ['normal', 'bold', '100', '200', '300', '400', '500', '600', '700', '800', '900']

src/Terminal.ts

@@ -85,7 +85,7 @@ const DEFAULT_OPTIONS: ITerminalOptions = {
   bellStyle: 'none',
   drawBoldTextInBrightColors: true,
   enableBold: true,
-  experimentalCharAtlas: 'static',
+  experimentalCharAtlas: 'dynamic',
   fontFamily: 'courier-new, courier, monospace',
   fontSize: 15,
   fontWeight: 'normal',

src/renderer/atlas/BaseCharAtlas.ts

@@ -4,6 +4,7 @@
  */
 
 import { IGlyphIdentifier } from './Types';
+import { IColor } from '../../shared/Types';
 
 export default abstract class BaseCharAtlas {
   private _didWarmUp: boolean = false;
@@ -51,3 +52,24 @@ export default abstract class BaseCharAtlas {
     y: number
   ): boolean;
 }
+
+/**
+ * Makes a partiicular rgb color in an ImageData completely transparent.
+ * @returns True if the result is "empty", meaning all pixels are fully transparent.
+ */
+export function clearColor(imageData: ImageData, color: IColor): boolean {
+  let isEmpty = true;
+  const r = color.rgba >>> 24;
+  const g = color.rgba >>> 16 & 0xFF;
+  const b = color.rgba >>> 8 & 0xFF;
+  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;
+    } else {
+      isEmpty = false;
+    }
+  }
+  return isEmpty;
+}

src/renderer/atlas/CharAtlasCache.ts

@@ -10,11 +10,9 @@ import { generateConfig, configEquals } from './CharAtlasUtils';
 import BaseCharAtlas from './BaseCharAtlas';
 import DynamicCharAtlas from './DynamicCharAtlas';
 import NoneCharAtlas from './NoneCharAtlas';
-import StaticCharAtlas from './StaticCharAtlas';
 
 const charAtlasImplementations = {
   'none': NoneCharAtlas,
-  'static': StaticCharAtlas,
   'dynamic': DynamicCharAtlas
 };
 

src/renderer/atlas/DynamicCharAtlas.ts

@@ -6,9 +6,8 @@
 import { DIM_OPACITY, IGlyphIdentifier, INVERTED_DEFAULT_COLOR } from './Types';
 import { ICharAtlasConfig } from '../../shared/atlas/Types';
 import { IColor } from '../../shared/Types';
-import BaseCharAtlas from './BaseCharAtlas';
+import BaseCharAtlas, { clearColor } from './BaseCharAtlas';
 import { DEFAULT_ANSI_COLORS } from '../ColorManager';
-import { clearColor } from '../../shared/atlas/CharAtlasGenerator';
 import LRUMap from './LRUMap';
 
 // In practice we're probably never going to exhaust a texture this large. For debugging purposes,

src/shared/atlas/Types.ts

@@ -9,7 +9,7 @@ import { IColorSet } from '../Types';
 export const CHAR_ATLAS_CELL_SPACING = 1;
 
 export interface ICharAtlasConfig {
-  type: 'none' | 'static' | 'dynamic';
+  type: 'none' | 'dynamic';
   devicePixelRatio: number;
   fontSize: number;
   fontFamily: string;

typings/xterm.d.ts

@@ -77,17 +77,10 @@ declare module 'xterm' {
      * artifacts.
      *
      * - 'none': Don't use an atlas.
-     * - 'static': Generate an atlas when the terminal starts or is reconfigured. This atlas will
-     *   only contain ASCII characters in 16 colors.
      * - 'dynamic': Generate an atlas using a LRU cache as characters are requested. Limited to
-     *   ASCII characters (for now), but supports 256 colors. For characters covered by the static
-     *   cache, it's slightly slower in comparison, since there's more overhead involved in
-     *   managing the cache.
-     *
-     * Currently defaults to 'static'. This option may be removed in the future. If it is, passed
-     * parameters will be ignored.
+     *   ASCII characters (for now), but supports 256 colors. (recommended)
      */
-    experimentalCharAtlas?: 'none' | 'static' | 'dynamic';
+    experimentalCharAtlas?: 'none' | 'dynamic';
 
     /**
      * The font size used to render text.
@@ -474,7 +467,7 @@ declare module 'xterm' {
      * (EXPERIMENTAL) Registers a character joiner, allowing custom sequences of
      * characters to be rendered as a single unit. This is useful in particular
      * for rendering ligatures and graphemes, among other things.
-     * 
+     *
      * Each registered character joiner is called with a string of text
      * representing a portion of a line in the terminal that can be rendered as
      * a single unit. The joiner must return a sorted array, where each entry is
@@ -483,16 +476,16 @@ declare module 'xterm' {
      * a single unit. When multiple joiners are provided, the results of each
      * are collected. If there are any overlapping substrings between them, they
      * are combined into one larger unit that is drawn together.
-     * 
+     *
      * All character joiners that are registered get called every time a line is
      * rendered in the terminal, so it is essential for the handler function to
      * run as quickly as possible to avoid slowdowns when rendering. Similarly,
      * joiners should strive to return the smallest possible substrings to
      * render together, since they aren't drawn as optimally as individual
      * characters.
-     * 
+     *
      * NOTE: character joiners are only used by the canvas renderer.
-     * 
+     *
      * @param handler The function that determines character joins. It is called
      * with a string of text that is eligible for joining and returns an array
      * where each entry is an array containing the start (inclusive) and end