[Oberon] Module Display: ReplPatternC (with clipping)?

[Tomas Kral]

On Tue, 26 Feb 2019 20:42:46 +0100
Jörg Straube <joerg.straube at iaeth.ch> wrote:

> no higher module with clipping functionality yet

My simple graph primitives, also lack, among other things, the
clipping.

Looking at PO2013 `Curves.Mod', I can see

  PROCEDURE Dot(f: GraphicFrames.Frame; col, x, y: INTEGER);
  BEGIN
    IF (x >= f.X) & (x+7 < f.X1) & (y >= f.Y) & (x+7 < f.Y1) THEN
      Display.Dot(col, x, y, Display.replace)
    END
  END Dot

Something I have evaded so far, as I am not sure, how to make clipping
for other regular or curved shapes.

I was thinking of setting a global default port (Display.Frame) or NIL
to avoid passing extra argument, but not sure if a good idea.

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