Organize temporary color handling code

src/renderer/BaseRenderLayer.ts

@@ -128,7 +128,10 @@ export abstract class BaseRenderLayer implements IRenderLayer {
     if (fg < 256) {
       colorIndex = fg + 1;
     }
-    if (code < 256 && (colorIndex > 0 || fg >= 256)) {
+    const isAscii = code < 256;
+    const isBasicColor = (colorIndex > 0 && fg < 16);
+    const isDefaultColor = fg >= 256;
+    if (isAscii && (isBasicColor || isDefaultColor)) {
       // ImageBitmap's draw about twice as fast as from a canvas
       const charAtlasCellWidth = this.scaledCharWidth + CHAR_ATLAS_CELL_SPACING;
       const charAtlasCellHeight = this.scaledCharHeight + CHAR_ATLAS_CELL_SPACING;

src/renderer/ColorManager.ts

@@ -23,7 +23,7 @@ export enum COLOR_CODES {
   BRIGHT_WHITE = 15
 }
 
-const DEFAULT_ANSI_COLORS = [
+export const DEFAULT_ANSI_COLORS = [
   // dark:
   '#2e3436',
   '#cc0000',

src/renderer/ForegroundRenderLayer.ts

@@ -101,7 +101,6 @@ export class ForegroundRenderLayer extends BaseRenderLayer {
         }
 
         const width: number = charData[CHAR_DATA_WIDTH_INDEX];
-
         this.drawChar(terminal, char, code, width, x, y, fg);
 
         this._ctx.restore();