Implement blink rendering

Fixes #944

src/common/services/OptionsService.ts

@@ -14,6 +14,7 @@ export const DEFAULT_OPTIONS: Readonly<Required<ITerminalOptions>> = {
   rows: 24,
   showCursorImmediately: false,
   cursorBlink: false,
+  blinkIntervalDuration: 0,
   cursorStyle: 'block',
   cursorWidth: 1,
   cursorInactiveStyle: 'outline',
@@ -168,6 +169,12 @@ export class OptionsService extends Disposable implements IOptionsService {
         }
         value = FONT_WEIGHT_OPTIONS.includes(value) ? value : DEFAULT_OPTIONS[key];
         break;
+      case 'blinkIntervalDuration':
+        value = Math.floor(value);
+        if (value < 0) {
+          throw new Error(`${key} cannot be less than 0, value: ${value}`);
+        }
+        break;
       case 'cursorWidth':
         value = Math.floor(value);
         // Fall through for bounds check

src/common/services/Services.ts

@@ -229,6 +229,7 @@ export interface ITerminalOptions {
   cols?: number;
   convertEol?: boolean;
   cursorBlink?: boolean;
+  blinkIntervalDuration?: number;
   cursorStyle?: CursorStyle;
   cursorWidth?: number;
   cursorInactiveStyle?: CursorInactiveStyle;