I've been working on this new unit for a while, it will make it much easier for someone to create a dos-program with application like interface.

The Windows, shadows, dialog boxes and everything!

Now i have one problem: You can put a Character somewhere on the screen using GotoXY and Write, but is there a way to Grab a Character from the screen.

For example i want to get the character at the point 40x17!

Please Help!<br>

: I've been working on this new unit for a while, it will make it much easier for someone to create a dos-program with application like interface.
:
: The Windows, shadows, dialog boxes and everything!
:
: Now i have one problem: You can put a Character somewhere on the screen using GotoXY and Write, but is there a way to Grab a Character from the screen.
:
: For example i want to get the character at the point 40x17!
:
: Please Help!
:
Nothing like this is built into Pascal, but there are 2 basic ways of doing it. One way is to request the proper service from BIOS using assembly. Otherwise you could just take a peek at the memory.

The info on the screen is stored starting at memory address $B800:0. Each character on the screen from left to right, top to bottom - uses 2 bytes: 1 for the ASCII code and 1 for the attributes like colour and blinking. This basic formula reads a character at (x,y) from the screen into a variable MyVar.

MyVar := Mem[$B800:x*2 + y*160];

Here's a trick. You can map an array to thte screen.

Type
   TextScreenChar = record
       Character: char;
       Attributes: byte;
   end;

Var
   TextScreen: array[1..25,1..40] of TextChar absolute $B800:0;

You want to read 40x17? It will be in TextScreen[17,40].Character

This code here counts x and y from 1 to 80 and 1 to 25, just like GotoXY (i.e. the top-left pixel is 1x1). The method I gave in my last post counted from 0 to 79 and 0 to 24 (i.e. the top-left pixel is at 0x0), so if you take that route remember to deduct 1 from your x and y.

: Here's a trick. You can map an array to thte screen.
:
:

: Type
:    TextScreenChar = record
:        Character: char;
:        Attributes: byte;
:    end;
: 
: Var
:    TextScreen: array[1..25,1..40] of TextChar absolute $B800:0;
: 

:
: You want to read 40x17? It will be in TextScreen[17,40].Character
:
: This code here counts x and y from 1 to 80 and 1 to 25, just like GotoXY (i.e. the top-left pixel is 1x1). The method I gave in my last post counted from 0 to 79 and 0 to 24 (i.e. the top-left pixel is at 0x0), so if you take that route remember to deduct 1 from your x and y.
:

wow, cool

: Here's a trick. You can map an array to thte screen.
:
:

: Type
:    TextScreenChar = record
:        Character: char;
:        Attributes: byte;
:    end;
: 
: Var
:    TextScreen: array[1..25,1..40] of TextChar absolute $B800:0;
: 

:
: You want to read 40x17? It will be in TextScreen[17,40].Character
:
: This code here counts x and y from 1 to 80 and 1 to 25, just like GotoXY (i.e. the top-left pixel is 1x1). The method I gave in my last post counted from 0 to 79 and 0 to 24 (i.e. the top-left pixel is at 0x0), so if you take that route remember to deduct 1 from your x and y.
:
:
That's cool. But what about 50 lines EGA or less than 80*25 lines (CO40+Font8x8)? How to make it there?

NetGert
Thanx[/b] in advance