From: "Paul Nicholls" <pauln@protel.com.au>
Subject: Re: Accessing a TBitmap with BASM
Date: 06 Aug 1999 00:00:00 GMT
Message-ID: <7od8oc$s3f12@forums.borland.com>
References: <7oagqi$pcp15@forums.borland.com>
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Reply-To: "Paul Nicholls" <pauln@protel.com.au>
Newsgroups: borland.public.delphi.basm

Thanks all for your help.  I did it in Pascal and then managed to access a
bitmap with assembly.  If anyone is interested in the code (probably not the
most efficient though) here it is...

unit frmBitmap;

interface

uses
 Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
 StdCtrls, ExtCtrls;

type
 TForm1 = class(TForm)
  procedure DrawFrame;
  procedure FormResize(Sender: TObject);
 private
  { Private declarations }
  Buffer : TBitmap;
 public
  { Public declarations }
 end;

var
 Form1  : TForm1;

implementation

{$R *.DFM}

procedure TForm1.DrawFrame;
var
 x,y   : integer;
 b_w,b_h : Integer;
 w,h   : Integer;
 P    : PWordArray;
 Delta  : LongInt;
 r,g,b  : LongInt;
begin
 Buffer := TBitmap.create;
 try
  Buffer.PixelFormat := pf16bit;
  Buffer.Width  := 320;
  Buffer.Height := 200;
  b_w := (Buffer.Width shr 1)-1;
  b_h := Buffer.Height-1;
  w  := ClientWidth-1;
  h  := ClientHeight-1;
  P := Buffer.ScanLine[0];
//    workout the next scanline offset and direction
  Delta := LongInt(Buffer.ScanLine[1])-LongInt(Buffer.ScanLine[0]);
  r := 31;
  g := 0;
  b := 0;
  Asm
   mov  eax,LongInt(P)
   xor  edx,edx
   xor  ecx,ecx
  @YLoop:
   push ecx
  @XLoop:
   shl  ecx,1
   push edx
   xor  edx,edx
   and  r,31
   and  g,63
   and  b,31
   or  edx,r
   shl  edx,5
   or  edx,g
   shl  edx,6
   or  edx,b

   shl  edx,16
   or  edx,r
   shl  edx,5
   or  edx,g
   shl  edx,6
   or  edx,b
//    fill in double word in bitmap
   mov  dword ptr[eax+ecx],edx
   pop  edx
   shr  ecx,1
   inc  ecx
   cmp  ecx,b_w
   jbe  @XLoop
   add  eax,Delta
   inc  edx
   cmp  edx,b_h
   pop  ecx
   jbe  @YLoop
  End;

StretchBlt(Canvas.Handle,0,0,w,h,Buffer.Canvas.Handle,0,0,b_w,b_h,SRCCOPY);
 finally
  Buffer.free;
 end;
end;
procedure TForm1.FormResize(Sender: TObject);
begin
 DrawFrame;
end;

end.

--
Paul Nicholls.
********************************************************
Live long and optimise
--------------------------------
Web Page : www.southcom.com.au/~phantom