troubles painting a simple bitmat pf32bit in linux lazarus version
lazarus / 39-Graphics

----------------------------------------------------------------------
dcelso · 2012-09-20 22:07

hello to all, I have created a simple example that runs well in
windows but in linux does not show anyting.
my form have only a timage in "alclient" and a tlavel to show if it is
in 32 bit mode.
Code: [Select]object Form1: TForm1
  Left = 461
  Height = 240
  Top = 195
  Width = 320
  Caption = 'Form1'
  ClientHeight = 240
  ClientWidth = 320
  OnShow = FormShow
  LCLVersion = '0.9.30.4'
  object Image1: TImage
    Left = 0
    Height = 240
    Top = 0
    Width = 320
    Align = alClient
    Center = True
  end
  object Label1: TLabel
    Left = 61
    Height = 1
    Top = 191
    Width = 1
    ParentColor = False
  end
end

And the pascal code only create on the event onshow a pf32bit with a
red square in the center.
Code: [Select]unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
ExtCtrls,
  StdCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)
    Image1: TImage;
    ImageList1: TImageList;
    Label1: TLabel;
    procedure FormShow(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.FormShow(Sender: TObject);
var
  img: TPicture;
  bmp: TBitmap;

begin
  img := TPicture.Create;
  img.Bitmap.PixelFormat := pf32bit;
  img.Bitmap.SetSize(150, 150);
  img.Bitmap.Canvas.Brush.Color := clRed;
  img.Bitmap.Canvas.FillRect(50, 50, 100, 100);
  image1.Picture.Assign(img);
  if img.Bitmap.PixelFormat = pf32bit then
  begin
    Label1.Caption := '32';
  end
  else
  begin
    Label1.Caption := '0';
  end;
  img.free;

end;

end.


I repeat that in windows it works well and in linux not.
¿What is the problem? ¿linux does not support  Bitmap with pixelformat
in pf32bits? or i have a problem.

If i change pf32bit for pf24bit or pf16bit or pf15bit it works
perfectly.

----------------------------------------------------------------------
Blaazen · 2012-09-20 23:12

Hi,

I tested and it works on both GTK2 and Qt4.
But I can see in the *.lfm file that you have LCLVersion 0.9.30.4
which a little old and I am sure there were many changes.
I tested with Lazarus 1.1 SVN.

You can also try to put there:
Code: [Select]  img.Bitmap.Canvas.Brush.Color := clBlack;
  img.Bitmap.Canvas.FillRect(0, 0, img.Bitmap.Width,
img.Bitmap.Height);   
after the SetSize method because 32bit mode has transparency.

So upgrade Lazarus and try your code again.

----------------------------------------------------------------------
dcelso · 2012-09-21 12:20

Thanks, in lazarus 1.0 runs well.
Now the alpha channel is not read or alwais is 255.
In this example I tried put the form in red color, and now i tried to
put a green square with a little scuare transparent inside to show the
red form color. But it not works.
the form is this:
Code: [Select]object Form1: TForm1
  Left = 514
  Height = 488
  Top = 303
  Width = 603
  Caption = 'Form1'
  ClientHeight = 488
  ClientWidth = 603
  Color = clRed
  OnShow = FormShow
  LCLVersion = '1.1'
  object Image1: TImage
    Left = 0
    Height = 488
    Top = 0
    Width = 603
    Align = alClient
    Transparent = True
  end
  object Label1: TLabel
    Left = 117
    Height = 21
    Top = 395
    Width = 9
    Caption = '0'
    ParentColor = False
  end
end
Using TBitmat my example is the next:
Code: [Select]unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
ExtCtrls,
  StdCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)
    Image1: TImage;
    Label1: TLabel;
    procedure FormShow(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.FormShow(Sender: TObject);
var
  bmp : TBitmap;
begin
  bmp:= TBitmap.Create;
  bmp.PixelFormat:=pf32bit;
  bmp.SetSize(150,150);
  bmp.Canvas.Brush.Color:= clGreen;
  bmp.Canvas.FillRect(20,20,130,130);
  bmp.Canvas.Brush.Color:= clNone;
  //bmp.Canvas.Brush.Style:=bsClear;
  //bmp.Canvas.Pen.Style:=psClear;
  bmp.Canvas.FillRect(50,50,100,100);
  Image1.Picture.assign(bmp);
  if Image1.Picture.Bitmap.PixelFormat = pf32bit then
  begin
       Label1.Caption:='32';
  end;
  bmp.Free;
end;

end.


I see a green windows but instead of color red I see white color. ;(

I tried change brush style and pen  but the result is not the correct,
too.


Using TPFImageBItmat my example is the next:
Code: [Select]unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
ExtCtrls,
  StdCtrls, FPImage,FPCanvas;

type

  { TForm1 }

  TForm1 = class(TForm)
    Image1: TImage;
    Label1: TLabel;
    procedure FormShow(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.FormShow(Sender: TObject);
var
  bmp : TFPImageBitmap;
begin
  bmp:= TBitmap.Create;
  bmp.SetSize(150,150);
  bmp.PixelFormat:=pf32bit;
  bmp.canvas.Brush.FPColor:= FPColor(255,0,0,255);
  bmp.canvas.FillRect(20,20,130,130);
  bmp.canvas.Brush.FPColor:= FPColor(0,0,0,0);
  bmp.canvas.FillRect(50,50,100,100);
  Image1.Picture.assign(bmp);
  if Image1.Picture.Bitmap.PixelFormat = pf32bit then
  begin
       Label1.Caption:='32';
  end;
  bmp.Free;
end;

end.
I see a black box instead of a green windows that shows the red color
inside it.

¿What is my error using TBitmat an TFPImageBitmap? I Think that im
doing the correct.