    gr.text_base must be updated 30fps in your Fs->draw_it() callback.  You probably
    want GrPrint() or just Print().  The DolDoc code takes care of plotting text to
    gr.text_base.

    Bits 0-7        8-Bit ASCII Scrn Code
    Bits 8-11       Foreground color
    Bits 12-15      Background color
    Bits 16-20      Signed X pos shift val
    Bits 21-25      Signed Y pos shift val
    Bit  28         Blink
    Bit  29         Inverted (Swap foreground and background)
    Bit  30         Sel (XOR colors with FF)
    Bit  31         Underline

    GrUpdateTaskWin() calls DocUpdateTaskDocs() which calls DocRecalc() where the
    document text is plotted into gr.text_base.  Then, GrUpdateTextBG() and
    GrUpdateTextFG() render the gr.text_base onto gr.dc2, a raw graphic bitmap.

    See ::/Demo/Games/Maze.HC.