[SOLVED] Setting Transparency from Image Created by bgraThumbs

[zxandris]

Hi there, I've got the following code.

Code: Pascal  [Select][+][-]

1.       Thumb := TBgraBitmap.create(0,0);
2.       try
3.          thumb.SetSize(pnlImageContainer.width, pnlImageContainer.height);
4.          try
5.             GetFileThumbnail(AnsiToUTF8(fname), pnlImageContainer.width, pnlImageContainer.height, $001E1E1E, false, thumb);
6.             if assigned(thumb) then
7.             begin
8.                 rst.x := thumb.width;
9.                 rst.y := thumb.Height;
10.                 propSize.x := thumb.width;
11.                 propSize.y := thumb.height;
12.             end;
13.          except
14.                Thumb.setSize(0,0);
15.                rst.x := 0;
16.                rst.y := 0;
17.          end;
18.          try
19.             Bgra.SetSize(Thumb.Width, thumb.height);
20.             Bgra.Assign(thumb);
21.          except
22.                bgra.setSize(0,0);
23.                rst.x := 0;
24.                rst.y := 0;
25.          end;
26.       except
27.             Bgra.setSize(0,0);
28.       end;
29.  

Now as you can see that load's a bgra bitmap, it returns a massive blotch of color where I was hoping it would be nothing, and if I use clNone, it still does.  I was wondering if there was anyway to set that color to say clFuschia and then turn that into transparent pixels for the display?

Any help would be most appreciated.

CJ

[Josh]

what happens if you set the size and fill on creation, note donot use the setsize after.

Code: Pascal  [Select][+][-]

1. Thumb := TBgraBitmap.Create(pnlImageContainer.width, pnlImageContainer.height,ColorToBGRA(clWhite,0));
2.  

[zxandris]

what happens if you set the size and fill on creation, note donot use the setsize after.

Code: Pascal  [Select][+][-]

1. Thumb := TBgraBitmap.Create(pnlImageContainer.width, pnlImageContainer.height,ColorToBGRA(clWhite,0));
2.  

Essentially it just writes white.  No Transparency

Code: Pascal  [Select][+][-]

1.      try
2.          try
3.             GetFileThumbnail(AnsiToUTF8(fname), pnlImageContainer.width-5, pnlImageContainer.height-5, ColorToBGRA($001E1E1E), false, BGRA); //
4.             if assigned(BGRA) then
5.             begin
6.                 rst.x := Bgra.width;
7.                 rst.y := Bgra.Height;
8.                 propSize.x := Bgra.width;
9.                 propSize.y := bgra.height;
10.             end;
11.          except
12.                bgra.setSize(0,0);
13.                rst.x := 0;
14.                rst.y := 0;
15.          end;
16.      except
17.             Bgra.setSize(0,0);
18.             rst.x := 0;
19.             rst.y := 0;
20.      end;
21.  

Is what I've got now, seems faster all told.  Also BGRA is a global BgraBitmap that get's painted to a panel.

[Josh]

just done a quick example.
not sure if its what u afer though.

edit: updated tpanel and tshape

[zxandris]

just done a quick example.
not sure if its what u afer though.

edit: updated tpanel and tshape

For some reason, doing what you do with the color doesn't seem to work for me.  I now have, (due to dealing with special file formats), the following, and as you can see I set the transparency.

Code: Pascal  [Select][+][-]

1.      ext := lowercase(ExtractFileExt(fname));
2.      try
3.          if pos(ext, cntSpecialLoad)>0 then
4.          begin
5.               try
6.                  LoadToBgra(fname, bgra);
7.                  rst.x := bgra.Width;
8.                  rst.y := bgra.Height;
9.                  PropSize.x := rst.x;
10.                  PropSize.Y := rst.y;
11.               except
12.                     rst.x := 0;
13.                     rst.y := 0;
14.                     BGRA.SetSize(0,0);
15.               end;
16.          end else if ext = '.png' then
17.          begin
18.              try
19.                 LoadToBgra(fname, bgra);
20.                 rst.x := bgra.Width;
21.                 rst.y := bgra.Height;
22.                 PropSize.x := rst.x;
23.                 PropSize.Y := rst.y;
24.              except
25.                    rst.x := 0;
26.                    rst.y := 0;
27.                    BGRA.SetSize(0,0);
28.              end;
29.          end else
30.          begin
31.              try
32.                 GetFileThumbnail(AnsiToUTF8(fname), pnlImageContainer.width, pnlImageContainer.height, ColorToBGRA($001E1E1E, 255), false, BGRA);
33.                 if assigned(BGRA) then
34.                 begin
35.                     rst.x := Bgra.width;
36.                     rst.y := Bgra.Height;
37.                     propSize.x := Bgra.width;
38.                     propSize.y := bgra.height;
39.                 end;
40.              except
41.                    bgra.setSize(0,0);
42.                    rst.x := 0;
43.                    rst.y := 0;
44.              end;
45.          end;
46.      except
47.             Bgra.setSize(0,0);
48.             rst.x := 0;
49.             rst.y := 0;
50.      end;
51.      pnlImagePaint(self);
52.  

I honestly don't know what I'm doing wrong, I tried replacing 255 with 0 in case I had that the wrong way around and that didn't work.  My bg is automatically checkered, so I should be able to see it if that was nil right/?

[circular]

Hello zxandris,

I understand you're having difficulty in having a transparent background.

Have you tried giving BGRAPixelTransparent as background color? That is the simplest way to specify a transparent color.

Also note that when you paint it on the panel, the parameter Opaque is to be set to False in order to render with transparency.

Regards

[zxandris]

Hello zxandris,

I understand you're having difficulty in having a transparent background.

Have you tried giving BGRAPixelTransparent as background color? That is the simplest way to specify a transparent color.

Also note that when you paint it on the panel, the parameter Opaque is to be set to False in order to render with transparency.

Regards

Okay that for some reason didn't work so, just in case I'm missin something

Code: Pascal  [Select][+][-]

1. procedure TframeImageBrowser.pnlImagePaint(Sender: TObject);
2. begin
3.     if assigned(bgra) then
4.     begin
5.         CalculateSizePos;
6.         if (Bgra.width<>0) and (bgra.height<>0) then
7.         begin
8.             if rst.x<>BGRA.width then
9.             begin
10.                  BGRA.Draw(pnlImage.canvas, RECT(0,0, rst.x, rst.y), false);
11.             end else
12.             begin
13.                  BGRA.Draw(pnlImage.canvas, RECT(0,0, PropSize.x, PropSize.y), false);
14.             end;
15.         end;
16.     end;
17.     try
18.        if assigned(BGRA) then pnlImage.Visible := true
19.        else pnlImage.Visible := false;
20.     except
21.            //
22.     end;
23. end;    
24.  

That's what I use to paint a global var of Bgrabitmap

and this is where I'm loading (JPG for testing)

Code: Pascal  [Select][+][-]

1.              try
2.                 GetFileThumbnail(AnsiToUTF8(fname), pnlImageContainer.width, pnlImageContainer.height, BGRAPixelTransparent, false, BGRA);
3.                 if assigned(BGRA) then
4.                 begin
5.                     rst.x := Bgra.width;
6.                     rst.y := Bgra.Height;
7.                     propSize.x := Bgra.width;
8.                     propSize.y := bgra.height;
9.                 end else
10.                 begin
11.                   bgra.setSize(0,0);
12.                   rst.x := 0;
13.                   rst.y := 0;
14.                   PropSize := rst;
15.                 end;
16.              except
17.                    bgra.setSize(0,0);
18.                    rst.x := 0;
19.                    rst.y := 0;
20.              end;
21.  

So far nothing is working and I'm a little confused why not to be honest.

[zxandris]

NVM, I know what I was doing wrong there!  Idiot that I am, the pnl was painting a hard color, not a grid, and sized to the full size of the area it's painting, but I've fixed that now and it seems to be working.

Thanks Guys,


CJ.

[circular]

Ok, I am not sure I understand but I am glad it is solved. 

[zxandris]

Ok, I am not sure I understand but I am glad it is solved. 

Your tip for the transparency worked like a charm, but I was still drawing to a panel which had a fixed color.  I've made that a checkered grid, and now the image sits pretty

CJ

[circular]

Ok got it. Thanks for clarifying.