Split CharAtlas types and utility functions off

I'm starting to pull some changes off of my large WIP branch/commit that
adds an alternative dynamic character atlas. We're going to need to
support multiple CharAtlas implementations, and this should make that
easier.

src/renderer/CharAtlas.ts

@@ -5,22 +5,13 @@
 
 import { ITerminal } from '../Types';
 import { IColorSet } from './Types';
+import { ICharAtlasConfig } from './atlas/Types';
 import { isFirefox } from '../shared/utils/Browser';
 import { generateCharAtlas, ICharAtlasRequest } from '../shared/CharAtlasGenerator';
+import { generateConfig, configEquals } from './atlas/CharAtlasUtils';
 
 export const CHAR_ATLAS_CELL_SPACING = 1;
 
-interface ICharAtlasConfig {
-  fontSize: number;
-  fontFamily: string;
-  fontWeight: string;
-  fontWeightBold: string;
-  scaledCharWidth: number;
-  scaledCharHeight: number;
-  allowTransparency: boolean;
-  colors: IColorSet;
-}
-
 interface ICharAtlasCacheEntry {
   bitmap: HTMLCanvasElement | Promise<ImageBitmap>;
   config: ICharAtlasConfig;
@@ -96,41 +87,3 @@ export function acquireCharAtlas(terminal: ITerminal, colors: IColorSet, scaledC
   charAtlasCache.push(newEntry);
   return newEntry.bitmap;
 }
-
-function generateConfig(scaledCharWidth: number, scaledCharHeight: number, terminal: ITerminal, colors: IColorSet): ICharAtlasConfig {
-  const clonedColors = {
-    foreground: colors.foreground,
-    background: colors.background,
-    cursor: null,
-    cursorAccent: null,
-    selection: null,
-    ansi: colors.ansi.slice(0, 16)
-  };
-  return {
-    scaledCharWidth,
-    scaledCharHeight,
-    fontFamily: terminal.options.fontFamily,
-    fontSize: terminal.options.fontSize,
-    fontWeight: terminal.options.fontWeight,
-    fontWeightBold: terminal.options.fontWeightBold,
-    allowTransparency: terminal.options.allowTransparency,
-    colors: clonedColors
-  };
-}
-
-function configEquals(a: ICharAtlasConfig, b: ICharAtlasConfig): boolean {
-  for (let i = 0; i < a.colors.ansi.length; i++) {
-    if (a.colors.ansi[i] !== b.colors.ansi[i]) {
-      return false;
-    }
-  }
-  return a.fontFamily === b.fontFamily &&
-      a.fontSize === b.fontSize &&
-      a.fontWeight === b.fontWeight &&
-      a.fontWeightBold === b.fontWeightBold &&
-      a.allowTransparency === b.allowTransparency &&
-      a.scaledCharWidth === b.scaledCharWidth &&
-      a.scaledCharHeight === b.scaledCharHeight &&
-      a.colors.foreground === b.colors.foreground &&
-      a.colors.background === b.colors.background;
-}

src/renderer/atlas/CharAtlasUtils.ts

@@ -0,0 +1,47 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { ITerminal } from '../../Types';
+import { ITheme } from 'xterm';
+import { IColorSet } from '../Types';
+import { ICharAtlasConfig } from './Types';
+
+export function generateConfig(scaledCharWidth: number, scaledCharHeight: number, terminal: ITerminal, colors: IColorSet): ICharAtlasConfig {
+  const clonedColors = {
+    foreground: colors.foreground,
+    background: colors.background,
+    cursor: null,
+    cursorAccent: null,
+    selection: null,
+    ansi: colors.ansi.slice(0, 16)
+  };
+  return {
+    scaledCharWidth,
+    scaledCharHeight,
+    fontFamily: terminal.options.fontFamily,
+    fontSize: terminal.options.fontSize,
+    fontWeight: terminal.options.fontWeight,
+    fontWeightBold: terminal.options.fontWeightBold,
+    allowTransparency: terminal.options.allowTransparency,
+    colors: clonedColors
+  };
+}
+
+export function configEquals(a: ICharAtlasConfig, b: ICharAtlasConfig): boolean {
+  for (let i = 0; i < a.colors.ansi.length; i++) {
+    if (a.colors.ansi[i] !== b.colors.ansi[i]) {
+      return false;
+    }
+  }
+  return a.fontFamily === b.fontFamily &&
+      a.fontSize === b.fontSize &&
+      a.fontWeight === b.fontWeight &&
+      a.fontWeightBold === b.fontWeightBold &&
+      a.allowTransparency === b.allowTransparency &&
+      a.scaledCharWidth === b.scaledCharWidth &&
+      a.scaledCharHeight === b.scaledCharHeight &&
+      a.colors.foreground === b.colors.foreground &&
+      a.colors.background === b.colors.background;
+}

src/renderer/atlas/Types.ts

@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { FontWeight } from 'xterm';
+import { IColorSet } from '../Types';
+
+export const CHAR_ATLAS_CELL_SPACING = 1;
+export const INVERTED_DEFAULT_COLOR = -1;
+export const DIM_OPACITY = 0.5;
+
+export interface ICharAtlasConfig {
+  fontSize: number;
+  fontFamily: string;
+  fontWeight: FontWeight;
+  fontWeightBold: FontWeight;
+  scaledCharWidth: number;
+  scaledCharHeight: number;
+  allowTransparency: boolean;
+  colors: IColorSet;
+}