add a helper to make color opaque

src/browser/Color.test.ts

@@ -4,7 +4,7 @@
  */
 
 import { assert } from 'chai';
-import { blend, fromCss, toPaddedHex, toCss, toRgba, fromRgba } from 'browser/Color';
+import { blend, fromCss, toPaddedHex, toCss, toRgba, fromRgba, opaque } from 'browser/Color';
 
 describe('Color', () => {
   describe('blend', () => {
@@ -157,4 +157,26 @@ describe('Color', () => {
       assert.deepEqual(fromRgba(0xffffffff), [0xff, 0xff, 0xff, 0xff]);
     });
   });
+
+  describe('opaque', () => {
+    it('should make the color opaque', () => {
+      assert.deepEqual(opaque({ css: '#00000000', rgba: 0x00000000 }), { css: '#000000', rgba: 0x000000FF });
+      assert.deepEqual(opaque({ css: '#10101010', rgba: 0x10101010 }), { css: '#101010', rgba: 0x101010FF });
+      assert.deepEqual(opaque({ css: '#20202020', rgba: 0x20202020 }), { css: '#202020', rgba: 0x202020FF });
+      assert.deepEqual(opaque({ css: '#30303030', rgba: 0x30303030 }), { css: '#303030', rgba: 0x303030FF });
+      assert.deepEqual(opaque({ css: '#40404040', rgba: 0x40404040 }), { css: '#404040', rgba: 0x404040FF });
+      assert.deepEqual(opaque({ css: '#50505050', rgba: 0x50505050 }), { css: '#505050', rgba: 0x505050FF });
+      assert.deepEqual(opaque({ css: '#60606060', rgba: 0x60606060 }), { css: '#606060', rgba: 0x606060FF });
+      assert.deepEqual(opaque({ css: '#70707070', rgba: 0x70707070 }), { css: '#707070', rgba: 0x707070FF });
+      assert.deepEqual(opaque({ css: '#80808080', rgba: 0x80808080 }), { css: '#808080', rgba: 0x808080FF });
+      assert.deepEqual(opaque({ css: '#90909090', rgba: 0x90909090 }), { css: '#909090', rgba: 0x909090FF });
+      assert.deepEqual(opaque({ css: '#a0a0a0a0', rgba: 0xa0a0a0a0 }), { css: '#a0a0a0', rgba: 0xa0a0a0FF });
+      assert.deepEqual(opaque({ css: '#b0b0b0b0', rgba: 0xb0b0b0b0 }), { css: '#b0b0b0', rgba: 0xb0b0b0FF });
+      assert.deepEqual(opaque({ css: '#c0c0c0c0', rgba: 0xc0c0c0c0 }), { css: '#c0c0c0', rgba: 0xc0c0c0FF });
+      assert.deepEqual(opaque({ css: '#d0d0d0d0', rgba: 0xd0d0d0d0 }), { css: '#d0d0d0', rgba: 0xd0d0d0FF });
+      assert.deepEqual(opaque({ css: '#e0e0e0e0', rgba: 0xe0e0e0e0 }), { css: '#e0e0e0', rgba: 0xe0e0e0FF });
+      assert.deepEqual(opaque({ css: '#f0f0f0f0', rgba: 0xf0f0f0f0 }), { css: '#f0f0f0', rgba: 0xf0f0f0FF });
+      assert.deepEqual(opaque({ css: '#ffffffff', rgba: 0xffffffff }), { css: '#ffffff', rgba: 0xffffffFF });
+    });
+  });
 });

src/browser/Color.ts

@@ -51,3 +51,12 @@ export function toRgba(r: number, g: number, b: number, a: number = 0xFF): numbe
 export function fromRgba(value: number): [number, number, number, number] {
   return [(value >> 24) & 0xFF, (value >> 16) & 0xFF, (value >> 8) & 0xFF, value & 0xFF];
 }
+
+export function opaque(color: IColor): IColor {
+  const rgba = (color.rgba | 0xFF) >>> 0;
+  const [r, g, b] = fromRgba(rgba);
+  return {
+    css: toCss(r, g, b),
+    rgba
+  };
+}

src/browser/renderer/atlas/DynamicCharAtlas.ts

@@ -11,7 +11,7 @@ import { LRUMap } from 'browser/renderer/atlas/LRUMap';
 import { isFirefox, isSafari } from 'common/Platform';
 import { IColor } from 'browser/Types';
 import { throwIfFalsy } from 'browser/renderer/RendererUtils';
-import { fromRgba, toCss } from 'browser/Color';
+import { opaque } from 'browser/Color';
 
 // In practice we're probably never going to exhaust a texture this large. For debugging purposes,
 // however, it can be useful to set this to a really tiny value, to verify that LRU eviction works.
@@ -223,7 +223,7 @@ export class DynamicCharAtlas extends BaseCharAtlas {
 
   private _getForegroundColor(glyph: IGlyphIdentifier): IColor {
     if (glyph.fg === INVERTED_DEFAULT_COLOR) {
-      return this._config.colors.background;
+      return opaque(this._config.colors.background);
     } else if (glyph.fg < 256) {
       // 256 color support
       return this._getColorFromAnsiIndex(glyph.fg);
@@ -254,13 +254,7 @@ export class DynamicCharAtlas extends BaseCharAtlas {
       `${fontStyle} ${fontWeight} ${this._config.fontSize * this._config.devicePixelRatio}px ${this._config.fontFamily}`;
     this._tmpCtx.textBaseline = 'middle';
 
-    const fgColor = this._getForegroundColor(glyph);
-    this._tmpCtx.fillStyle = fgColor.css;
-
-    if (glyph.fg === INVERTED_DEFAULT_COLOR) {
-      const rgba = fromRgba(fgColor.rgba);
-      this._tmpCtx.fillStyle = toCss(rgba[0], rgba[1], rgba[2]);
-    }
+    this._tmpCtx.fillStyle = this._getForegroundColor(glyph).css;
 
     // Apply alpha to dim the character
     if (glyph.dim) {

src/browser/renderer/dom/DomRenderer.ts

@@ -11,7 +11,7 @@ import { IColorSet, ILinkifierEvent, ILinkifier } from 'browser/Types';
 import { ICharSizeService } from 'browser/services/Services';
 import { IOptionsService, IBufferService } from 'common/services/Services';
 import { EventEmitter, IEvent } from 'common/EventEmitter';
-import { fromRgba, toCss } from 'browser/Color';
+import { opaque } from 'browser/Color';
 
 const TERMINAL_CLASS_PREFIX = 'xterm-dom-renderer-owner-';
 const ROW_CONTAINER_CLASS = 'xterm-rows';
@@ -230,9 +230,8 @@ export class DomRenderer extends Disposable implements IRenderer {
           `${this._terminalSelector} .${FG_CLASS_PREFIX}${i} { color: ${c.css}; }` +
           `${this._terminalSelector} .${BG_CLASS_PREFIX}${i} { background-color: ${c.css}; }`;
     });
-    const rgba = fromRgba(this._colors.background.rgba);
     styles +=
-        `${this._terminalSelector} .${FG_CLASS_PREFIX}${INVERTED_DEFAULT_COLOR} { color: ${toCss(rgba[0], rgba[1], rgba[2])}; }` +
+        `${this._terminalSelector} .${FG_CLASS_PREFIX}${INVERTED_DEFAULT_COLOR} { color: ${opaque(this._colors.background).css}; }` +
         `${this._terminalSelector} .${BG_CLASS_PREFIX}${INVERTED_DEFAULT_COLOR} { background-color: ${this._colors.foreground.css}; }`;
 
     this._themeStyleElement.innerHTML = styles;