Question

I have a variable number of points on a canvas.
Sometime its four other times 3 points, or 6.
Is there a function that can paint the area inside?

Thank you for your help.

Answer 1

Use the TCanvas.Polygon function. Declare an array of TPoint, set its length to the count of your points, specify each point’s coordinates (optionally modify canvas pen and/or brush) and pass this array to the TCanvas.Polygon function. Like in this boring example:

procedure TForm1.Button1Click(Sender: TObject);
var
  Points: array of TPoint;
begin
  SetLength(Points, 3);
  Points[0] := Point(5, 5);
  Points[1] := Point(55, 5);
  Points[2] := Point(30, 30);
  Canvas.Pen.Width := 2;
  Canvas.Pen.Color := clRed;
  Canvas.Brush.Color := clYellow;
  Canvas.Polygon(Points);
end;

Here’s how it looks like: