Method _processUnderline

src/common/InputHandler.ts:2393–2412

* SGR 4 subparams: * 4:0 - equal to SGR 24 (turn off all underline) * 4:1 - equal to SGR 4 (single underline) * 4:2 - equal to SGR 21 (double underline) * 4:3 - curly underline * 4:4 - dotted underline * 4:5 - dashed underline

(style: number, attr: IAttributeData)

   *    4:5   -   dashed underline
   */
  private _processUnderline(style: number, attr: IAttributeData): void {
    // treat extended attrs as immutable, thus always clone from old one
    // this is needed since the buffer only holds references to it
    attr.extended = attr.extended.clone();

    // default to 1 == single underline
    if (!~style || style > 5) {
      style = 1;
    }
    attr.extended.underlineStyle = style;
    attr.fg |= FgFlags.UNDERLINE;

    // 0 deactivates underline
    if (style === 0) {
      attr.fg &= ~FgFlags.UNDERLINE;
    }

    // update HAS_EXTENDED in BG
    attr.updateExtended();
  }

  private _processSGR0(attr: IAttributeData): void {
    attr.fg = DEFAULT_ATTR_DATA.fg;