[SOLVED] FloodFill on Canvas
lazarus / 39-Graphics

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gafe · 2015-01-04 11:14

Hi:

In my way to learn, i'm trying to implement a penrose tiling program
(from one in python http://preshing.com/20110831/penrose-tiling-
explained/). I'm almost there as you can see in attached image, but
i'm drawing in a canvas and want to fill the triangles, but floodfill
doesn't work (here it's linux with gtk).

I have read http://bugs.freepascal.org/view.php?id=2001 and understand
that maybe it's not implemented for gtk. I followed FloodFill until i
get to intfbasewinapi.inc which have:

Code: [Select]function TWidgetSet.FloodFill(DC: HDC; X, Y: Integer;
  Color: TGraphicsColor;
  FillStyle: TGraphicsFillStyle;
  Brush: HBRUSH): Boolean;
begin
  Result := false;
end;   

My question is: if it's not implemented, there's another easy way to
do it? I have found a implementation on a german forum that works with
a bitmap (http://www.lazarusforum.de/viewtopic.php?f=25&t=3891

As always..thank you.

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Blaazen · 2015-01-04 12:52

Probably it is not implemented (I did a quick test and GTK2 and Qt
cannot do floodfill) but the code you linked is not proof.
TWidgetSet is abstract class, you should look elsewhere - depend on
your widgetset.

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gafe · 2015-01-04 15:29

I tried on windows:

Code: [Select] with Form1.Canvas do
  begin
  Pen.Color:=clWhite;
  Moveto(50,50);
  LineTo(100,50);
  Lineto(100,100);
  Lineto(50,100);
  LineTo(50,50);
  Brush.Color:=clgreen;
  FloodFill(60,60,Form1.canvas.Pixels[60,60],fssurface);
  end;
and works well, surely it's not implemented.I'll try to adapt the code
from the german forum to a canvas, or paint in a bitmap instead of a
paintbox.

Thanks.

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Carver413 · 2015-01-04 22:17

http://en.wikipedia.org/wiki/Flood_fill
A simple 4 point recursive flood is pretty easy to implement. Thanks
for the link, I'm always interested it stuff like this as I am working
on a procedural engine for designing textures for games an such.

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gafe · 2015-01-18 13:48

If someone comes here with this problem, I solved it using Canvas2D
from BGRABitmap, it is the same canvas as in javascript. Works well in
all platforms.