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VIDPOINT.PAS
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Pascal/Delphi Source File
|
1990-06-14
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2KB
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93 lines
Unit VidPoint;
INTERFACE
USES DOS;
{ Returns a pointer to the current hardware cursor position: }
FUNCTION CursorPointer : Pointer;
{ Returns a pointer to screen buffer address corresponding to X,Y: }
FUNCTION XYPointer(X,Y : Integer) : Pointer;
{ Writes count attribute bytes at hardware cursor position:}
PROCEDURE WriteAttribute(Attribute : Byte; Count : Integer);
IMPLEMENTATION
{ Returns a pointer to the current hardware cursor position: }
FUNCTION CursorPointer : Pointer;
VAR
Regs : Registers;
Origin : Word;
BEGIN
WITH Regs DO
BEGIN
Intr($11,Regs); { Call Equipment Configuration Information }
IF AX AND $0030 = $0030 THEN Origin := $B000 ELSE
Origin := $B800;
{ Obtain the current cursor position from BIOS: }
AH := $03; BH := 0;
Intr($10,Regs);
{ Cursor row is now in DH; Column in DL; calculate offset of }
{ cursor into video refresh buffer & make a pointer: }
CursorPointer := Ptr(Origin,(DH * 160) + (DL * 2));
END;
END;
{ Returns a pointer to screen buffer address corresponding to X,Y: }
FUNCTION XYPointer(X,Y : Integer) : Pointer;
VAR
Regs : Registers;
Origin : Word;
BEGIN
WITH Regs DO
BEGIN
Intr($11,Regs); { Call Equipment Configuration Information }
IF AX AND $0030 = $0030 THEN Origin := $B000 ELSE
Origin := $B800;
Dec(X); Dec(Y); { Adjust X & Y to 0-origin }
XYPointer := Ptr(Origin,(Y * 160) + (X * 2));
END;
END;
{ Writes count attribute bytes at hardware cursor position:}
PROCEDURE WriteAttribute(Attribute : Byte; Count : Integer);
TYPE
VidArray = ARRAY[0..4096] OF Byte;
VidArrayPtr = ^VidArray;
VAR
I : Integer;
BEGIN
FOR I := 1 TO Count*2 DO
IF Odd(I) THEN VidArrayPtr(CursorPointer)^[I] := Attribute;
END;
{ No initialization section }
END.