Why can't I get "Simple example" for BGRABitmap to work?

[stab]

Hi,

Lazarus: ver 1.1
OS:         Windows 7/64bit
FPC:        ver. 2.7.1
SVN:        rev. 39352MP

Have tried to copy the code in "Simple example" for BGRABitmap like:

unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, BGRABitmap,
  BGRABitmapTypes, BGRATransform, BGRAGraphicControl;

type

  { TForm1 }

  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormPaint(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;
  bmp: TBGRABitmap;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.FormCreate(Sender: TObject);
begin
  bmp := TBGRABitmap.Create(100,100,BGRABlack); //creates a 100x100 pixels image with black background

   bmp.FillRect(20,20,60,60,BGRAWhite, dmSet); //draws a white square without transparency
   bmp.FillRect(40,40,80,80,BGRA(0,0,255,128), dmDrawWithTransparency); //draws a transparent blue square
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  bmp.Free;
end;

procedure TForm1.FormPaint(Sender: TObject);
begin
  bmp.Draw(Canvas, 0, 0, True); // draw the bitmap in opaque mode (faster)
end;

end.

But nothing is displayed.

What am i doing wrong?

Regards
stab

[Jurassic Pork]

hello Stab,

i have no problem to display the bitmap with your code with Lazarus windows 7 svn 1.1 Bgrabitmappack 7.2 .
The last version of bgrabitmap is here : http://sourceforge.net/p/lazpaint/code/HEAD/tree/bgrabitmap/

Friendly, J.P

[stab]

Thanks for answering,

Followed your suggestion and got Bgrabitmappack 7.2, but same result as before.
As a test I added:
  bmp.SaveToFile(ExtractFilepath(Application.Exename) + 'bml.png'); right after

  bmp.FillRect(40,40,80,80,BGRA(0,0,255,128), dmDrawWithTransparency); //draws a transparent blue square

and could verify that the calls to BGRABitmap had worked OK.

Of some peculiar drawing to a canvas doesn't work

/stab

[exdatis]

Try to find answer:
http://wiki.freepascal.org/BGRABitmap_tutorial
Regards

[User137]

Did you just straight copy-paste the code like that, or did you also link the FormCreate and so on to the TForm1 object in the IDE?

[circular]

It should work. Put a breakpoint on the bmp.Draw instruction: does it go through that instruction?

[marcov]

Invalidate the form, so the system knows it should generate paint events for it?

Just add invalidate after the call.