WPF PathGeometry Fill

Question

I'm running into a problem with WPF and PathGeometry. I have the following Path object which is a combination of lines and arcs.

<Path Data="M100,180L220,180 M220,180L220,152 M220,152L217,150
M217,150L182,150 M180,147L180,132 M182,130L217,130 M217,130L220,127
M220,127L220,80 M220,80L100,80 M100,80L100,180 M182,150L180,147
M180,132L182,130">

Here's a simple code snippet that should draw the entire shape.

private void DrawIt()
{
    Canvas canv = new Canvas();
    this.Content = canv;
    canv.Margin = new Thickness(0, 0, 0, 0);
    canv.Background = new SolidColorBrush(Colors.White);

    Path testPath = GetPath("blue");
    testPath.Data = Geometry.Parse("M100,180L220,180 M220,180L220,152 M220,152L217,150 M217,150L182,150 M180,147L180,132 M182,130L217,130 M217,130L220,127 M220,127L220,80 M220,80L100,80 M100,80L100,180 M182,150L180,147 M180,132L182,130 ");
    var area = testPath.Data.GetArea();

    canv.Children.Add(testPath);
    this.Content = canv;
}

private Path GetPath(string aColor)
{
    Path imagePath = new Path();
    SolidColorBrush colorBrush = (SolidColorBrush)new BrushConverter().ConvertFromString(aColor);
    imagePath.Stroke = colorBrush;
    imagePath.StrokeThickness = 2;
    imagePath.Fill = colorBrush;

    return imagePath;
}

The code above results in the following image:

Resulting image

My problem is that I'm trying to get the area of this image, but Path.Data.GetArea() only ever returns 0.0.

Any help would be appreciated.

You should include the code, otherwise it's hard to provide the answer based on pure guessing. Rgds, — Alexander Bell, Jul 01 '14 at 13:43
Sorry, first time actually posting on here. I usually just read the questions. — MADC0D3R, Jul 01 '14 at 13:53
Your "path" data doesn't seem to contain any arcs, and also appears to describe several disjoint lines because it keeps `M`oving the current point even though, generally, it's `M`oving to the same point it was already at (although there are two exceptions). — Damien_The_Unbeliever, Jul 01 '14 at 13:56
Is there a way to close those points? In other words make them one contiguous line? — MADC0D3R, Jul 01 '14 at 14:00

score 0 · Answer 1 · answered Jul 01 '14 at 14:01

0

You're describing multiple figures, all of them just single straight lines, because you keep issuing Move commands. If your path data was like this:

M100,180L220,180 220,152 217,150 182,150 180,147 180,132 182,130 217,130 220,127
         220,80 100,80 Z

It instead describes a single figure that should draw the same shape you've shown but should also be fillable.

See Path Markup Syntax

answered Jul 01 '14 at 14:01

Damien_The_Unbeliever

234,701
27
340
448

Damien, thanks for the advice. Unfortunately the problem is that this is not something I generated myself. I'm taking in coordinates from a CSV file and essentially drawing the lines and arcs based on that. I guess what I'd really like to know is if there is a way to generate your path data from mine and close those holes. – MADC0D3R Jul 01 '14 at 14:07
@MADC0D3R - depends on how "clean"/"safe" the input is - if there's no maliciousness behind the input and they're aiming for a single closed shape then you parse each line as pairs of "start x,y", "end x,y" in some kind of dictionary. Then you take one item from the dictionary, emit `M` and "start x,y" and then `L` and "end x,y" - then you loop around and find the next line whose "start x,y" matches the previous "end x,y" and just emit that line's "end x,y". Continue until you've gotten back to the original "start x,y" point. – Damien_The_Unbeliever Jul 01 '14 at 14:15

WPF PathGeometry Fill

1 Answers1