Creating a terminal menu with scrollable text

[gunghopatriot]

I am using a terminal only so no GUI and using Free Pascal 2.6.2. If I have a screen that begins on line 5 I can use the arrow keys to move down to say line 26, and if I get to line 27 it goes back to line 5, and line 4 wraps to line 25. All good and works with enter if a line is selected.

My problem is, if I have text that is say 100 lines long, I want to keep using the arrow keys go down, and if at line 27, line 27 moves to line 26 and line 26 to line 25 and line 5 would be removed from view.

Does anyone have an example of how to accomplish this?

 

[mikrom]

Isn't it dependent only of your terminal window settings ?
For examle in Windows you can set Screen Buffer Size, which means how many lines has your command scrren.
See this for example:

http://delltech.150m.com/XP/dos/4.htm

 

[Glenn9999]

I pulled out an old text viewer project in Turbo Pascal which was rather interesting to see still works in Windows 8. Anyhow, there's a lot there, but here's a clue on how I handled it (too much here to repost the whole thing):

 { header changed along with corresponding calls }
  procedure processdown(textarray: array of Pchar; textstring: string;
               var beginline: integer; var endline: integer;
               totallines: integer);
    begin
      if endline < totallines then
        begin
          gotoxy(1,2);
          delline;
          beginline := beginline + 1;
          endline := endline + 1;
          gotoxy(1,25);
          write(textarray[endline]);
          redrawtop(textstring);
        end;
    end;

{ header changed along with all corresponding calls }
  procedure processup(textarray: array of Pchar; textstring: string;
             var beginline: integer; var endline: integer);
    begin
      if beginline <> 0 then
        begin
          gotoxy(1,2);
          insline;
          beginline := beginline - 1;
          endline := endline - 1;
          write(textarray[beginline]);
          redrawtop(textstring);
        end;
    end;

This is what gets called when the user presses the DOWN or UP key. RedrawTop() is just a procedure that puts a status line on the top of the screen that says "Viewing <XYZ>, Press F1 for Help", nothing relevant to what your question is. Textarray is the place where the text lines are stored in memory.

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