[Oberon] System-V - Frame Clipping

[Tomas Kral]

Hi,

It sounded here recently, the idea of clipping. My understanding is that
any dot screen trajectory, needs asserting against min/max, to be well
within sensible bounds.

I am thinking along these lines.

PROCEDURE Handle(F: Display.Frame; VAR M: Display.FrameMsg);
BEGIN
  CASE F OF Frame:
    CASE M OF
      Oberon.InputMsg:
        IF ~ F.focus THEN Oberon.PassFocus(); (*acquire focus*)
          F.focus := TRUE; Clip(F) (*clipping ON*)
        END
    | Oberon.ControlMsg:
        IF M.id = Oberon.defocus THEN (*give up focus*)
          F.focus := FALSE; Clip(NIL) (*clipping OFF*)
        END
    END (*M*)
  END (*F*)
END Handle;

I wish to do actual clipping H/W.
How difficult this could be, if not too silly an idea?

Many thanks for reading this.

-- 
Tomas Kral <thomas.kral at email.cz>