[Oberon] SystemV - Viewer Scroll

[Tomas Kral]

On Thu, 14 Mar 2019 21:36:28 +0100
Andreas Pirklbauer <andreas_pirklbauer at yahoo.com> wrote:

> Using ‘CopyBlock' to optimize scrolling in *both* directions

Hi Andreas,

Thank you, looking into your code. I wish, however to understand the
original first.

 PROCEDURE Show* (F: Frame; pos: LONGINT);
  (* driven by delta pos - F.org *) 
  IF pos < F.org THEN (*???*)
  ELSIF pos > F.org THEN (*???*)
  ELSIF pos = F.org THEN (*???*)
    (*use of CopyBlock()*)
  ELSE (*???*)
  END ;
 END Show;

 PROCEDURE Edit* (F: Frame; X, Y: INTEGER; Keys: SET);
   IF Keys = {2} THEN   (*ML, scroll up*)
   ELSIF Keys = {1} THEN   (*MM*) (*!!! up or down !!!*)
   ELSIF Keys = {0} THEN   (*MR, scroll down*)
   END ;
   Show(....);
 END Edit;
 
-- 
Tomas Kral <thomas.kral at email.cz>