Tile image as background
lazarus / 39-Graphics

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BenJones · 2011-05-17 11:12

Hi i am new here, can someone point me in the right way to title a
background image on a form, I been makeing a little CDMenu frontend
and now I like to have the form background as a image.

Thanks

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BenJones · 2011-05-17 11:59

Ok I am trying some code to sort the problum here is what I have

Code: [Select]var
   b : TBrush;
   rc : TRect;
begin
  b := Tbrush.Create;
  b.Bitmap := ImgBrush.Picture.Bitmap;
  frmmain.Canvas.Brush := b;
  SetRect(rc,0,0,self.Width ,self.Height);
  frmmain.Canvas.FillRect(rc);
  b.Free;

But i get an error while running the code

unit1.pas(218,10) Error: Identifier not found "SetRect"
unit1.pas(219,29) Warning: Local variable "rc" does not seem to be
initialized
unit1.pas(255) Fatal: There were 1 errors compiling module, stopping

It seems like I am missing something but not sure this is what I got
in my uses

  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
StdCtrls,
  ExtCtrls, inifiles,ShellApi,Unit2,MMSystem;


Any ideas were I am going wrong thanks.

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Blaazen · 2011-05-17 12:19

For painting on canvas of form, you should move your code to OnPaint
event of form, otherwise it does not work (at least here - Linux+Qt).
Instead of SetRect use this:
Code: [Select]var rc: TRect;
begin
  rc:=Rect(0, 0, self.Width, self.Height);
You want tiles, i.e. fill background with one small image repeated
vertically and horizontally?

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BenJones · 2011-05-17 12:32

Hi thanks that works perfect also moved my code to on paint .
but I still like to know why setrect did not work did I have something
wrong in the uses.

Thanks agian.

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BenJones · 2011-05-17 13:12

Ok i found out what I was missing i was missing windows from the uses.

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garlar27 · 2011-05-17 13:20

You don't need to create a TBrush, it's already there, ready to be
used.

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Leledumbo · 2011-05-17 15:27

QuoteOk i found out what I was missing i was missing windows from the
uses.So don't use it if you want your app to stay cross platform.

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BenJones · 2011-05-17 16:57

I took the create brush out but it gave me an error

Project project1.exe raised exception class 'External: SIGSEGV'.
but when I put it back in it was ok

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Blaazen · 2011-05-17 17:39

Did you removed both "b:=TBrush.Create" and "b.Free;" ?

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BenJones · 2011-05-17 21:03

Hi yes removed borth still same errors here my code

code is called form OnPaint Event

Code: [Select]procedure TextureForm();
  var
   b : TBrush;
   rc : TRect;
begin
  b.Bitmap := frmmain.ImgBrush.Picture.Bitmap;
  //Set form brush
  frmmain.Canvas.Brush := b;
  //Set the size to draw, Thanks to Blaazen for helping with this Rect
Thing
  rc := Rect(0,0,frmmain.Width,frmmain.Height);
  //Fill form with brush
  frmmain.Canvas.FillRect(rc);
end;

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Blaazen · 2011-05-17 21:12

Quote from: garlar27 on May 17, 2011, 03:20:10 pmYou don't need to
create a TBrush, it's already there, ready to be used.
garlar27 probably meant do it directly without "b", then you don't
need to create and free it:
Code: [Select]procedure TextureForm();
  var  rc : TRect;
begin
  //Set form brush
  frmmain.Canvas.Brush.Bitmap := frmmain.ImgBrush.Picture.Bitmap;
Note I work with graphic only sometimes.

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BenJones · 2011-05-17 21:26

Thanks Blaazen that works fine now. Now I can finish thie project and
start on my new project idea, thanks agian for the help. It realy
helpfull.

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davesimplewear · 2011-05-18 03:22

I don't believe in reinventing the wheel, JanTilePanel does the job.

Regards
Dave

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Gintas · 2011-09-28 19:45

I wonder how to do the same with TBGRABitmap canvas. The example code
in "testbgrafunc" which draw tile background doesn't make much sense
to me.

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lainz · 2011-09-28 22:43

Quote from: Gintas on September 28, 2011, 09:45:00 pmI wonder how to
do the same with TBGRABitmap canvas. The example code in
"testbgrafunc" which draw tile background doesn't make much sense to
me.

First load the image. Then you need to use the GetPart procedure. And
finally draw to the form.

Code: [Select]procedure TForm1.FormCreate(Sender: TObject);
begin
  background := TBGRABitmap.Create('diamondback.png');
end;

procedure TForm1.BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);
var
  tile: TBGRABitmap;
begin
  tile := background.GetPart(rect(0,0,Width,Height)) as TBGRABitmap;
  Bitmap.PutImage(0,0,tile,dmSet);
  tile.Free;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  background.Free;
end;
In that case I was using a BGRAVirtualScreen, but you can draw OnPaint
event of the form.

Code: [Select]procedure TForm1.FormPaint(Sender: TObject);
var
  tile: TBGRABitmap;
begin
  tile := background.GetPart(rect(0,0,Width,Height)) as TBGRABitmap;
  tile.Draw(Canvas,0,0);
  tile.Free;
end;   
Edit: If you want to use the existing image just replace the creation
of the background:
Code: [Select] background :=
TBGRABitmap.Create(ImgBrush.Picture.Bitmap);

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lainz · 2011-09-28 23:17

BTW I've added a new property 'Tile' in BGRASpriteAnimation in the git
repository of BGRAControls.

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circular · 2011-09-28 23:39

That's right Lainz, you can use GetPart.

You can also use the Fill method. Instead of writing
Code: [Select]var
  tile: TBGRABitmap;
begin
  tile := background.GetPart(rect(0,0,Width,Height)) as TBGRABitmap;
  Bitmap.PutImage(0,0,tile,dmSet);
  tile.Free;
end;
You can write
Code: [Select]begin
  Bitmap.Fill(background);
end;

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lainz · 2011-11-13 14:55

I can fill transparent bitmap?

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circular · 2011-11-13 16:02

Of course, with FillTransparent method.

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lainz · 2011-11-13 16:12

My question is if I can fill a bitmap with transparent area with
Bitmap1.Fill(Bitmap2); (bitmap2 has alpha pixels);

You can add procedure TBGRADefaultBitmap.Fill(texture: IBGRAScanner); 
 with a new option transparent: boolean, or drawmode: TDrawMode;

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circular · 2011-11-13 16:22

Ah ok, you mean when there are alpha pixels, they are blended and you
would like to use dmSet mode instead ?

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lainz · 2011-11-13 18:08

Quote from: circular on November 13, 2011, 05:22:57 pmAh ok, you mean
when there are alpha pixels, they are blended and you would like to
use dmSet mode instead ?

They aren't blended with Fill(bitmap) because by default is dmSet in:

Code: [Select]procedure TBGRADefaultBitmap.Fill(texture:
IBGRAScanner);
begin
  FillRect(FClipRect.Left,FClipRect.Top,FClipRect.Right,FClipRect.Bott
om,texture,dmSet);
end;  
BTW I've solved the problem using FillRect.

Code: [Select]battleroom.FillRect(0, 0, battleroom.Width,
battleroom.Height, grid, dmDrawWithTransparency);

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circular · 2011-11-13 22:16

Ok. I've added Fill(IBGRAScanner, TDrawMode) on subversion

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lainz · 2011-11-14 00:53

Thx