[Oberon] SystemV - Viewer Scroll

[Joerg]

Tomas

With the following command you can read "one character in backward
direction":
  Files.Set(R, Files.Base(R), Files.Pos(R)-1);
  Files.Read(R, ch);

br
Jörg

-----Original Message-----
From: Oberon <oberon-bounces at lists.inf.ethz.ch> On Behalf Of Tomas Kral
Sent: Tuesday, March 19, 2019 5:07 PM
To: oberon at lists.inf.ethz.ch
Subject: Re: [Oberon] SystemV - Viewer Scroll

On Tue, 19 Mar 2019 13:23:08 +0100
Joerg <joerg.straube at iaeth.ch> wrote:

> Forward scrolling:

Taken from `Show' proc, this is forward reading in single chars from `Texts'
stream.

  Texts.OpenReader(R, F.text, org); Texts.Read(R, nextCh);
  WHILE ~L.eot & (curY >= botY) DO
    NEW(L0); DisplayLine(F, L0, R, F.X + F.left, curY, 0);
    L.next := L0; L := L0; curY := curY - lsp
  END;

> Backward scrolling:
Backward reading by single a char does not seem possible, or does it?

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