Arrows and highlighting

[gwar2k1]

Hey, just a few questions about arrow keys and doing the menu thing where it "highlights" a selection...

To use the arrow keys which are extended ASCII, I use this function:

FUNCTION keyread:integer;

VAR
value:integer;

BEGIN
value := ord(upcase(readkey));
IF value = 0 THEN
value := ord(readkey) + 300;
keyread := value;
END;

This works, however, I have to press the key twice before I get a result. I cant think of why it does this nor can I work out how to get rid of it =(
Do you guys use any other function to retrieve extended ASCII that works when you press the key once? lol

OK, so with that - and I guess every othe function with the same purpose - the arrow keys are 372: Up and 380: Down.
In a CASE keyread OF <value> I have an IF.

IF y > (highest menu positon) THEN
BEGIN
y = y + 1
item = item - 1
bgcolor : white
text : black
gotoxy(x{set},y)
writeln(array[item])
...

That displays the highlighted item from the array &quot;on top&quot; of the one that wasnt highlighted.

...
bgcolor(black)
text(white)
gotoxy(x,y-1)
writeln(array[item-1])
END

So that *should* write the previous selection in the &quot;normal&quot; colors, though it doesnt work 100% I really dont know why, If it can work once it can work twice right? lol wrong! =S
Of course, the down IF has y - 1 and item + 1 etc.

Besides it not working all the time, there is no way with that method to highlight the 1st item then clear it. Same with the last item. Again, I dont understand why. In theory that should work.

It could just be my tempramental Turbo Pascal (7.1) but Im not sure.

So there's the second plea: Highlighting techniques.

Sorry to be greedy just I dip in to this area of design occasionally and over a period of two years Ive still yet to come up with a solution that works! Yes, I am slow =P

Thanks for your time

~*Gwar3k1*~
&quot;To the pressure, everything's just like: an illusion. I'll be losing you before long...&quot;

 

[gwar2k1]

OK, ive been testing and i can now get it to highlight in the correct place when the menu is placed any where on screen BUT now for some unknown reason the keys arent working =(

PROGRAM test;

PROCEDURE writeln(x,y:byte; s:string);
{display procedure. allows frames to be placed full screen and removes the need for gotoxy}

VAR
i,j : word;
color : word;
sreenwidth : integer;
screenheight : integer;

BEGIN
IF (x = 0) OR (y = 0) THEN
exit;
x := x + lo(Windmin)-1;
y := y + hi(Windmin)-1;
IF (x > lo(windmax)) OR (y > hi(windmax)) THEN
exit;
IF x+length(s)-1 > lo(windmax) THEN
s := copy(s, 1, lo(windmax)-x+1);
sreenwidth := memw[Seg0040:$4a];
i := ( y * SreenWidth + x ) * sizeof(word);
color := textattr;
color := color shl 8;
FOR j := 1 TO length(s) DO
BEGIN
memw[segB800:i] := color OR ord(s[j]);
inc(i,2);
END;
END;

PROCEDURE clrscr(x1,y1,x2,y2:byte);

VAR
i,y : integer;

BEGIN
y := y1 - 1;
REPEAT
y := y + 1;
FOR i := x1 TO x2 DO
writeln(i,y,' ');
UNTIL y = y2;
END;

PROCEDURE menu(s:ARRAY OF string; x,y,h,m:integer);
{(s)tring, (h)ighlighted // y axis, (m)enu_size}

VAR
b,c : integer; {(b)lank_space, (c)urrent, (l)ength}

BEGIN
m := m - 1;
FOR c := 0 TO m DO
BEGIN
IF c = h - 1 THEN
BEGIN
textcolor(black);
textbackground(lightgray);
END
ELSE
BEGIN
textcolor(lightgray);
textbackground(black);
END;
FOR b := 1 TO 10 DO
writeln(x+b,y,#32);
writeln(x,y+c,s[c]);
END;
END;

PROCEDURE menu2(VAR key:char; VAR y,m,z:integer);

BEGIN
REPEAT
key := readkey;
UNTIL key IN [#13,#72,#80];
CASE key OF
#72 : y := y - 1;
#80 : y := y + 1;
END;
IF y < z THEN
y := m;
IF y > (z + m) THEN
y := z;
END;

CONST
s : ARRAY [0..8] OF string = ('A','B','C','D','E','F','G','H','I');

VAR
y,m,z : integer;
key : char;

BEGIN
y := 1;
m := 8;
z := y;
clrscr(1,1,80,50);
menu(s,1,y,1,m);
REPEAT
menu2(key,y,m,z);
UNTIL key = #13;
END.

Thats the program im using to test it and in theory it should work. =@( Can any one help me please?


~*Gwar3k1*~
&quot;To the pressure, everything's just like: an illusion. I'll be losing you before long...&quot;

 

[Bertv100]

You replace the writeln procedure with your own version, you shouldn't do that! Besides, your version is rather complicated; a procedure writexy containing gotoxy and write should do the job perfectly.

You replace the clrscr procedure with your own version, again: you shouldn't do that! Clrscr clears the active screen window, if you want to wipe a rectangular part of the screen, you can use the window procedure to define a new window, perform a clrscr and reset the window to the full screen size.

The reason why your keys don't seem to work is that you don't react on a keypress; you adjust the y value in menu2, you stay in the main repeat-until loop and you call menu2 again. No displaying in between?!

One other remark: pressing 'P' will have the same result as pressing ArrDn and pressing 'H' will have the same effect as pressing ArrUp. Use the following:

repeat
  ch:=readkey;
  if ch=#0 then ch2:=readkey;
until (ch in [#13]) or ((ch=#0) and (ch2 in [#72,#80]));

Regards,
Bert Vingerhoets
vingerhoetsbert@hotmail.com

http://student.vub.ac.be/~bvingerh/

Don't worry what people think about you. They're too busy wondering what you think about them.

 

[gwar2k1]

lmao i cant believe i just did that! ive been a lil distracted to day so um sorry for wasting your time but thanks for the readkey stuff, I was pondering woulding H and P have the same effect.
Ive used window thrice before. ... yeah I get confused with it, it was never something i particularly needed. Any who, back to the code I go =D

Thanks again

~*Gwar3k1*~
&quot;To the pressure, everything's just like: an illusion. I'll be losing you before long...&quot;