force alpha to 1 when using background color as inverted foreground color.

src/browser/renderer/atlas/DynamicCharAtlas.ts

@@ -11,6 +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';
 
 // 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.
@@ -253,7 +254,13 @@ export class DynamicCharAtlas extends BaseCharAtlas {
       `${fontStyle} ${fontWeight} ${this._config.fontSize * this._config.devicePixelRatio}px ${this._config.fontFamily}`;
     this._tmpCtx.textBaseline = 'middle';
 
-    this._tmpCtx.fillStyle = this._getForegroundColor(glyph).css;
+    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]);
+    }
 
     // Apply alpha to dim the character
     if (glyph.dim) {

src/browser/renderer/dom/DomRenderer.ts

@@ -11,6 +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';
 
 const TERMINAL_CLASS_PREFIX = 'xterm-dom-renderer-owner-';
 const ROW_CONTAINER_CLASS = 'xterm-rows';
@@ -229,8 +230,9 @@ 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: ${this._colors.background.css}; }` +
+        `${this._terminalSelector} .${FG_CLASS_PREFIX}${INVERTED_DEFAULT_COLOR} { color: ${toCss(rgba[0], rgba[1], rgba[2])}; }` +
         `${this._terminalSelector} .${BG_CLASS_PREFIX}${INVERTED_DEFAULT_COLOR} { background-color: ${this._colors.foreground.css}; }`;
 
     this._themeStyleElement.innerHTML = styles;