Lazarus

Programming => Packages and Libraries => Topic started by: MoellerCLaus on July 15, 2021, 02:35:51 pm

Title: BGRA: Displaying BGRABitMap in Virtual screen
Post by: MoellerCLaus on July 15, 2021, 02:35:51 pm

In
procedure TForm1.VirtualScreenRedraw(Sender: TObject; Bitmap: TBGRABitmap);

How do I display a bitmap loaded from a file or drawn in another TBGRABitmap?

Bitmap.EllipseAntialias(Swimmer_Images[A].Left,
           TopOffset + A*LaneHeight + LaneHeight Div 2,
           10, 10, BGRABlack, 1, Swimmer_Images[A].SColor);
works fine - taken from the balls example from the virtualscreen demo.

I miss Bitmap.DrawBitmap(bitmap.BGRABitMap,x,y,true) ?

Title: Re: BGRA: Displaying BGRABitMap in Virtual screen
Post by: mosquito on July 15, 2021, 04:54:35 pm

this work for me... button1 load image and put in memory. button2 put image from memory to virtualscreen.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls,
9.   BGRAVirtualScreen, BGRABitmap, BCTypes, BGRABITMAPTYPES;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     BGRAVirtualScreen1: TBGRAVirtualScreen;
17.     Button1: TButton;
18.     Button2: TButton;
19.     Memo1: TMemo;
20.     procedure BGRAVirtualScreen1Exit(Sender: TObject);
21.     procedure BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap: TBGRABitmap);
22.     procedure Button1Click(Sender: TObject);
23.     procedure Button2Click(Sender: TObject);
24.   private
25.  
26.   public
27.   BMP1 : TBGRABITMAP ;
28.   end;
29.  
30. var
31.   Form1: TForm1;
32.  
33. implementation
34.  
35. {$R *.lfm}
36.  
37. { TForm1 }
38.  
39. procedure TForm1.Button1Click(Sender: TObject);
40. begin
41.   if FileExists('sample.png') then begin
42.     BMP1 := TBGRABITMAP.CREATE('sample.png');
43.     MEMO1.CLEAR;
44.     MEMO1.Lines.Add('sample.png loaded');
45.  
46.   end else begin
47.     showmessage('sample.png not in path');
48.   end;
49. end;
50.  
51. procedure TForm1.Button2Click(Sender: TObject);
52. begin
53.   BGRAVirtualScreen1.RedrawBitmap;
54. end;
55.  
56. procedure TForm1.BGRAVirtualScreen1Exit(Sender: TObject);
57. begin
58. BMP1.FREE;
59. end;
60.  
61. procedure TForm1.BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap: TBGRABitmap);
62. begin
63. BITMAP.PUTIMAGE(0,0,BMP1,dmset,255);
64.  
65. end;
66.  
67. end.
68.  
69.  

Title: Re: BGRA: Displaying BGRABitMap in Virtual screen
Post by: winni on July 15, 2021, 04:57:06 pm

Hi!

The VirtualScreen owns a BGRAbitmap.

For drawing from one BGRAbitmap to another you use:

Code: Pascal  [Select][+][-]

1. MainBGRAbitmap.putImage (x,y, SourceBGRAbitmap, TDrawMode);
2.  

where TDrawMode is defined in bgrapixel.inc as:

Code: Pascal  [Select][+][-]

1.  
2. TDrawMode = (
3.     {** The pixel is replaced }
4.     dmSet,
5.     {** The pixel is replaced if the pixel over has an alpha value of 255 }
6.     dmSetExceptTransparent,
7.     {** The pixel is blend over the other one according to alpha values,
8.         however no gamma correction is applied. In other words, the color
9.         space is assumed to be linear }
10.     dmLinearBlend,
11.     {** The pixel is blend over the other one according to alpha values,
12.         and a gamma correction is applied. In other word, the color
13.         space is assumed to be sRGB }
14.     dmDrawWithTransparency,
15.     {** Values of all channels are combined with Xor. This is useful to
16.         compute the binary difference, however it is not something that makes
17.         much sense to display on the screen }
18.     dmXor);
19.  

Winni

Title: Re: BGRA: Displaying BGRABitMap in Virtual screen
Post by: MoellerCLaus on July 15, 2021, 10:02:33 pm

 ;) Thank you both - just what I was looking for. It works perfectly :-[