Passing a bitmap to DLL using handle to it

do you write the dll yourself?

I modified the contents of the button click event to draw to the second bitmap and show that both update...

procedure TForm1.Button1Click(Sender: TObject);
begin
  Bitmap2.Handle := Bitmap1.Handle;
  with Bitmap2, Canvas do
    begin
      MoveTo(0, 0);
      LineTo(99, 99);
    end;
  PaintBox1.Invalidate;
  PaintBox2.Invalidate;
end;

Select allOpen in new window

I'm afraid that's not what you looking for but that's best solution I've come up with

library BMPDLL;

uses
  SysUtils,
  Classes,
  Windows,
  Graphics;

{$R *.res}

procedure MakeColorAnalysis3(var Bitmap: HBITMAP);stdcall;
var bmp: TBitmap;
begin
  bmp := TBitmap.Create;
  try
    bmp.Handle := Bitmap;
    with TBitmap.Create do begin
      Assign(bmp);
      Canvas.MoveTo(0, 0);
      Canvas.LineTo(256, 256);
      Bitmap := Handle;
    end;
  finally
    bmp.Free;
  end;  
end;

exports
  MakeColorAnalysis3;

begin
end.

EXE:
interface
procedure MakeColorAnalysis3(var Bitmap: HBITMAP);stdcall;
implementation
procedure MakeColorAnalysis3;external 'bmpdll.dll' name 'MakeColorAnalysis3';

procedure TForm1.Button6Click(Sender: TObject);
var h: HBITMAP;
begin
  h := Image1.Picture.Bitmap.Handle;
  MakeColorAnalysis3(h);
  Image1.Picture.Bitmap.Handle := h;
end;

ziolko.

I've also found some C++ code that supposedly lets you access raw bmp bits represented by HBITMAP (so there's no need to create additional bmp in DLL and re-assign Handle on EXE side) but can't make it work all I got is scrambled image.

ziolko.

 with TmpBMP do begin
      ReleaseHandle;    
      Assign(bmp);
      Canvas.MoveTo(0, 0);

ziolko.

any progress on this one?


ziolko.