[SOLVED] BGRAGraphic Control - Redraw - Disappearing Bitmap on Scrollbox

[pixelink]

Now, I decided to put the BGRAGraphicControl inside a Scrollbox.

Now that disappears too.

Tried this code on Scrollbox Paint and Resize events... nothing works.
The same code below works on FormResize if I don't use scrollbox though

Now what?

Code: Pascal  [Select][+][-]

1. if StartUp = False Then
2.     if (nb.PageIndex = 1) Or (nb.PageIndex = 2) Then
3.        begin
4.           BGRAGraphicControl1.Bitmap.Assign(theBMP.Bitmap);
5.           BGRAGraphicControl2.Bitmap.Assign(newBMP.Bitmap);
6.           BGRAGraphicControl2Redraw(Sender,newBMP);
7.  
8.        end  

[circular]

Hi.

It does not make sense to assign to the Bitmap property or to call the Redraw event yourself. The Redraw event is called automatically by the component itself. If you consider that the Bitmap is to be redrawn you can call DiscardBitmap. This will trigger the Redraw event and invalidate the component so that it will be repainted.

The logic about what is on the component is expected to be in the Redraw event. There the program can decide what you would like to display.

For example, this draws a red ellipse in the middle of a BGRAGraphicControl that is inside a scrollbox:

Code: Delphi  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, BGRAGraphicControl, BGRABitmap;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     BGRAGraphicControl1: TBGRAGraphicControl;
16.     ScrollBox1: TScrollBox;
17.     procedure BGRAGraphicControl1Redraw(Sender: TObject; Bitmap: TBGRABitmap);
18.   private
19.  
20.   public
21.  
22.   end;
23.  
24. var
25.   Form1: TForm1;
26.  
27. implementation
28.  
29. uses BGRABitmapTypes;
30.  
31. {$R *.lfm}
32.  
33. { TForm1 }
34.  
35. procedure TForm1.BGRAGraphicControl1Redraw(Sender: TObject; Bitmap: TBGRABitmap);
36. begin
37.   Bitmap.FillEllipseAntialias(Bitmap.Width/2-0.5,Bitmap.Height/2-0.5, Bitmap.Width/3,Bitmap.Height/3, CSSRed);
38. end;
39.  
40. end.  

[pixelink]

I have tried discard and it didn't work for me
Also, I am not loading images at startup so doing everything on ReDraw doesn't work.
The reason I don'y have everything drawing on the Redraw event is because when I load the test images, it is a onetime thing

Here is how I load/redraw my bitmaps (only pertinent code)

1) Declare my var's

Code: Pascal  [Select][+][-]

1.  
2. var
3.   Form1: TForm1;
4.   TheImage1: TBGRABitmap;
5.   TheImage2: TBGRABitmap;
6.   theBMP: TBGRABitmap;
7.   newBMP: TBGRABitmap;
8.   startUp: Boolean = True;
9.  
10.  

2) I use Notebook for multiple pages.
When form loads a it displays "loading" button. (this will be where a user creates or loads a project)
When the "Load" button is clicked it loads three images (transparent PNG, and two character PNG's)

FYI... the transparent PNG is to eliminate the Black screen I get if I don't assign a bitmap when the control displays.
This also will be needed once I remove the two other test character PNGs.
i simulate the checkered background (and use the transparent PNG because I will be resizing the actual controls and if I turn off AutoSize, then the checkered look will remain correct.

Eventually a person will be loading more images as pseudo layers

Code: Pascal  [Select][+][-]

1.  
2. procedure TForm1.Button1Click(Sender: TObject);
3. begin
4.     nb.PageIndex:=1;
5.  
6.     theBMP:= TBGRABitmap.Create('transpatentmask.png');
7.     BGRAGraphicControl1.Bitmap.Assign(theBMP);
8.     newBMP:= TBGRABitmap.Create('transpatentmask.png');
9.     BGRAGraphicControl2.Bitmap.Assign(newBMP);
10.  
11.     btnDesign.Enabled:=True;
12.     mnuDesign.Enabled:=True;
13.  
14.     TheImage1:= TBGRABitmap.Create('style_01.png');
15.     TheImage2:= TBGRABitmap.Create('style_02.png');
16.  
17.     theBMP.PutImage(0, 0, TheImage1, dmDrawWithTransparency );
18.     theBMP.PutImage(0, 0, TheImage2, dmDrawWithTransparency );  //dmLinearBlend or dmDrawWithTransparency
19.  
20.     BGRAGraphicControl1.Bitmap.Assign(theBMP);
21.     BGRAGraphicControl1.Refresh;
22.  
23. end;
24.  
25.  

3) Here is my redraw prod

Code: Pascal  [Select][+][-]

1.  
2. procedure TForm1.BGRAGraphicControl1Redraw(Sender: TObject; Bitmap: TBGRABitmap);
3. begin
4.   BGRAGraphicControl1.Bitmap.Assign(theBMP.Bitmap);
5.  
6.   if assigned(TheImage1) then
7.   begin
8.     TheImage1.Draw(Canvas,0,0,false); //true makes it opaque - false makes transparent
9.  
10.   end;
11.  
12.   if assigned(TheImage2) then
13.   begin
14.     TheImage2.Draw(Canvas,0,0,false); //true makes it opaque - false makes transparent
15.  
16.   end;
17.  
18.   if assigned(theBMP) then
19.   begin
20.     theBMP.Draw(Canvas,0,0,false); //true makes it opaque - false makes transparent
21.  
22.   end;
23. end;
24.  
25. procedure TForm1.BGRAGraphicControl2Redraw(Sender: TObject; Bitmap: TBGRABitmap
26.   );
27. begin
28.   BGRAGraphicControl2.Refresh;
29.   //BGRAGraphicControl2Paint(Sender);
30.  
31.   if assigned(newBMP) then
32.   begin
33.     newBMP.Draw(Canvas,0,0,false); //true makes it opaque - false makes transparen
34.   end;
35.  
36. end;
37.  
38.  

4) Here is all my resize code

Code: Pascal  [Select][+][-]

1.  
2. procedure TForm1.FormResize(Sender: TObject);
3. begin
4.   if StartUp = False Then
5.     if (nb.PageIndex = 1) Or (nb.PageIndex = 2) Then
6.        begin
7.           BGRAGraphicControl1.Bitmap.Assign(theBMP.Bitmap);
8.           BGRAGraphicControl2.Bitmap.Assign(newBMP.Bitmap);
9.           BGRAGraphicControl2Redraw(Sender,newBMP);
10.           //BGRAGraphicControl2.DiscardBitmap;
11.        end
12. end;
13.  
14. procedure TForm1.FormDestroy(Sender: TObject);
15. begin
16.   TheImage1.Free;
17.   TheImage2.Free;
18.   theBMP.Free;
19.   newBMP.Free;
20. end;
21.  
22. procedure TForm1.ScrollBox3Resize(Sender: TObject);
23. begin
24.     if StartUp = False Then
25.     if (nb.PageIndex = 1) Or (nb.PageIndex = 2) Then
26.        begin
27.           //BGRAGraphicControl1.Bitmap.Assign(theBMP.Bitmap);
28.           //BGRAGraphicControl2.Bitmap.Assign(newBMP.Bitmap);
29.           BGRAGraphicControl2Redraw(Sender,newBMP);
30.  
31.        end
32. end;
33.  
34. procedure TForm1.ScrollBox3Paint(Sender: TObject);
35. begin
36.     if StartUp = False Then
37.     if (nb.PageIndex = 1) Or (nb.PageIndex = 2) Then
38.        begin
39.           BGRAGraphicControl1.Bitmap.Assign(theBMP.Bitmap);
40.           BGRAGraphicControl2.Bitmap.Assign(newBMP.Bitmap);
41.           BGRAGraphicControl2Redraw(Sender,newBMP);
42.  
43.        end
44. end;
45. end.
46.  
47.  

[pixelink]

Here is the actual project

On this project... only the "Design" page uses a scrollbox that has a BGRAGraphicControl on it

[lainz]

I think we need to remove the Bitmap property and OnPaint event, so is not misused, what do you think @circular?

[pixelink]

Solved it.

I put "BGRAGraphicControl1.Bitmap.Assign(theBMP);" on the redraw event.
I had it in the show event of the form

[circular]

Well, yes you need to define the content within the Redraw event.

But you are supposed to use the Bitmap parameter. Also not calling Draw event in this event.

I am confused about what you are trying to do. Simply display an image in the control?

Then it is much simpler than that. For example you can do this:

Code: Delphi  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, BGRAGraphicControl, BGRABitmap, BCTypes;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     BGRAGraphicControl1: TBGRAGraphicControl;
16.     procedure BGRAGraphicControl1Redraw(Sender: TObject; Bitmap: TBGRABitmap);
17.     procedure FormCreate(Sender: TObject);
18.   private
19.  
20.   public
21.     myImage: TBGRAbitmap;
22.   end;
23.  
24. var
25.   Form1: TForm1;
26.  
27. implementation
28.  
29. {$R *.lfm}
30.  
31. uses BGRABitmapTypes;
32.  
33. { TForm1 }
34.  
35. procedure TForm1.FormCreate(Sender: TObject);
36. begin
37.   myImage := TBGRABitmap.Create('style_01.png');
38. end;
39.  
40. procedure TForm1.BGRAGraphicControl1Redraw(Sender: TObject; Bitmap: TBGRABitmap);
41. begin
42.   //Bitmap.FillTransparent;
43.   Bitmap.PutImage(0,0,myImage, dmDrawWithTransparency);
44. end;
45.  
46. end.

To have the component fully transparent by default, set the property ColorOpacity to zero, BevelInner and BevelOuter to bvNone and Caption to an empty string. Alternatively you can call Bitmap.FillTransparent at the beginning of the Redraw event.