BGRABitmap tutorial

[WILL]

I was wondering about a water or ocean type effect on the background of the form or something like that. I think I know what the answer might be though.

[circular]

I'd like to play with this, but the FPC wiki seems to be down.

Yes, unfortunately. You can still have a look at the bgrafunctest folder in LazPaint archive. You can find it here :
http://sourceforge.net/projects/lazpaint/files/src/

I was wondering about a water or ocean type effect on the background of the form or something like that. I think I know what the answer might be though.

Well, it depends. You can precalculate an ocean texture. Then, just showing it is ok. But if you want to animate it, well, it would be too slow, except maybe with a very small texture.

[chronozphere]

Thanks. How can I install that lpk package? Can I move my source files after I have installed the package? (Really annoying that I have to ask this, because all the documentation for lazarus is inaccessible. )

Update: It seems like they have fixed the problem.

[circular]

Once the package is installed, you need to specify package dependency in the project inspector. Then you can move your project whereever you want.

[chronozphere]

I have a little problem. I want to draw a closed polygon, but it doesn't work:

var
  image: TBGRABitmap;
  storedSpline: array of TPointF;
  c: TBGRAPixel;
begin
  image := TBGRABitmap.Create(ClientWidth,ClientHeight,ColorToBGRA(ColorToRGB(clBtnFace)));
  c := ColorToBGRA(ColorToRGB(clWindowText));

  setLength(storedSpline, 3);
  storedSpline[0].x := 50;
  storedSpline[0].y := 50;
  storedSpline[1].x := 100;
  storedSpline[1].y := 100;
  storedSpline[2].x := 0;
  storedSpline[2].y := 100;

  image.DrawPolylineAntialias(storedSpline,c,1, true); //This call should draw a closed spline

  image.Draw(Canvas,0,0,True);
  image.free;
end;

The last parameter is called Closed, so I presume that when I pass true, I will get a closed spline, but It's still open.
Anybody?

[circular]

It's normal. A polyline is not a closed figure. The closed parameter means that the end of the segment is closed. See here :
http://wiki.lazarus.freepascal.org/B...map_tutorial_6

If you want to draw a closed path, then use DrawPolygonAntialias.

By the way, naming a variable storedSpline does not automatically create a spline. You need to call ComputeClosedSpline. See here :
http://wiki.lazarus.freepascal.org/B...map_tutorial_7

If you feel the tutorial is ambiguous somewhere, please tell me what you suggest to add or change.

[chronozphere]

Thanks! It works great now.

By the way, naming a variable storedSpline does not automatically create a spline. You need to call ComputeClosedSpline. See here :

Don't pay attention to that name. I was reusing that name from another piece of code that did use a spline.