Move rest of atlas implementations to atlas dirs

Moves CharAtlas into src/renderer/atlas/ and CharAtlasGenerator into
src/shared/atlas/.

src/renderer/atlas/CharAtlas.ts

@@ -0,0 +1,87 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { ITerminal } from '../../Types';
+import { IColorSet } from '../Types';
+import { ICharAtlasConfig } from './Types';
+import { isFirefox } from '../../shared/utils/Browser';
+import { generateCharAtlas, ICharAtlasRequest } from '../../shared/atlas/CharAtlasGenerator';
+import { generateConfig, configEquals } from './CharAtlasUtils';
+
+interface ICharAtlasCacheEntry {
+  bitmap: HTMLCanvasElement | Promise<ImageBitmap>;
+  config: ICharAtlasConfig;
+  ownedBy: ITerminal[];
+}
+
+let charAtlasCache: ICharAtlasCacheEntry[] = [];
+
+/**
+ * Acquires a char atlas, either generating a new one or returning an existing
+ * one that is in use by another terminal.
+ * @param terminal The terminal.
+ * @param colors The colors to use.
+ */
+export function acquireCharAtlas(terminal: ITerminal, colors: IColorSet, scaledCharWidth: number, scaledCharHeight: number): HTMLCanvasElement | Promise<ImageBitmap> {
+  const newConfig = generateConfig(scaledCharWidth, scaledCharHeight, terminal, colors);
+
+  // Check to see if the terminal already owns this config
+  for (let i = 0; i < charAtlasCache.length; i++) {
+    const entry = charAtlasCache[i];
+    const ownedByIndex = entry.ownedBy.indexOf(terminal);
+    if (ownedByIndex >= 0) {
+      if (configEquals(entry.config, newConfig)) {
+        return entry.bitmap;
+      } else {
+        // The configs differ, release the terminal from the entry
+        if (entry.ownedBy.length === 1) {
+          charAtlasCache.splice(i, 1);
+        } else {
+          entry.ownedBy.splice(ownedByIndex, 1);
+        }
+        break;
+      }
+    }
+  }
+
+  // Try match a char atlas from the cache
+  for (let i = 0; i < charAtlasCache.length; i++) {
+    const entry = charAtlasCache[i];
+    if (configEquals(entry.config, newConfig)) {
+      // Add the terminal to the cache entry and return
+      entry.ownedBy.push(terminal);
+      return entry.bitmap;
+    }
+  }
+
+  const canvasFactory = (width: number, height: number) => {
+    const canvas = document.createElement('canvas');
+    canvas.width = width;
+    canvas.height = height;
+    return canvas;
+  };
+
+  const charAtlasConfig: ICharAtlasRequest = {
+    scaledCharWidth,
+    scaledCharHeight,
+    fontSize: terminal.options.fontSize,
+    fontFamily: terminal.options.fontFamily,
+    fontWeight: terminal.options.fontWeight,
+    fontWeightBold: terminal.options.fontWeightBold,
+    background: colors.background,
+    foreground: colors.foreground,
+    ansiColors: colors.ansi,
+    devicePixelRatio: window.devicePixelRatio,
+    allowTransparency: terminal.options.allowTransparency
+  };
+
+  const newEntry: ICharAtlasCacheEntry = {
+    bitmap: generateCharAtlas(window, canvasFactory, charAtlasConfig),
+    config: newConfig,
+    ownedBy: [terminal]
+  };
+  charAtlasCache.push(newEntry);
+  return newEntry.bitmap;
+}