CODEWITHSUNDEEP
wpf
Newton Zou
Newton Zou

Reputation: 588

Geometry.Combine doesn't work for curves

I want to combine 2 curves like this: enter image description here Then here is my code:

// Create a path to draw a geometry with.
Path myPath = new Path();
myPath.Stroke = Brushes.Black;
myPath.StrokeThickness = 1;
var gmy1 = (StreamGeometry)StreamGeometry.Parse("M100,100C110,118.333333333333 138.333333333333,206.666666666667 160,210 181.666666666667,213.333333333333 205,123.333333333333 230,120 255,116.666666666667 280,186.666666666667 310,190 340,193.333333333333 396.666666666667,156.666666666667 410,140 423.333333333333,123.333333333333 393.333333333333,98.3333333333333 390,90");
var gmy2 = (StreamGeometry)StreamGeometry.Parse("M180,241.25L180,241.25 230,290 300,246.66667175293 330,160");
var gmy = Geometry.Combine(gmy1, gmy2, GeometryCombineMode.Union, null);
myPath.Data = gmy;
// Add path shape to the UI.
this.panel1.Children.Add(myPath);

But the result is this:

enter image description here

How to combine the curves in WPF? And because of the project limitation, we have to implement this without layout and xaml. That means we need the result type is Geometry.

Upvotes: 1

Views: 231

Answers (3)

15ee8f99-57ff-4f92-890c-b56153
15ee8f99-57ff-4f92-890c-b56153

Reputation: 37060

Easy:

Path myPath = new Path();
myPath.Stroke = Brushes.Black;
myPath.StrokeThickness = 1;
var gmy1 = (StreamGeometry)StreamGeometry.Parse("M100,100C110,118.333333333333 138.333333333333,206.666666666667 160,210 181.666666666667,213.333333333333 205,123.333333333333 230,120 255,116.666666666667 280,186.666666666667 310,190 340,193.333333333333 396.666666666667,156.666666666667 410,140 423.333333333333,123.333333333333 393.333333333333,98.3333333333333 390,90");
var gmy2 = (StreamGeometry)StreamGeometry.Parse("M180,241.25L180,241.25 230,290 300,246.66667175293 330,160");

var gmy = (StreamGeometry)StreamGeometry.Parse(gmy1.ToString() + gmy2.ToString());

myPath.Data = gmy;
// Add path shape to the UI.
this.panel1.Children.Add(myPath);

The path definition language is a language. Use it as one. StreamGeometry.ToString() unparses a Geometry back to its Path Definition Language representation, which you can then merge with another one.

Note that this works because each starts with a M for Move command: It starts a new line. I don't think there's any realistic case where you'd run into any trouble with that (and it won't let you start with L for Line), but theory's not exactly my strongest subject.

Upvotes: 1

Clemens
Clemens

Reputation: 128013

More general than concatenating path strings:

If you have a set of arbitrary Geometries and want to group them, use a GeometryGroup:

Geometry gmy1 = ...;
Geometry gmy2 = ...;
var gmy = new GeometryGroup();
gmy.Children.Add(gmy1);
gmy.Children.Add(gmy2);
myPath.Data = gmy;

Upvotes: 3

brunnerh
brunnerh

Reputation: 184306

Just add both of them to a Grid or Canvas, Combine does a intersecting combination, you just seem to want to overlay them. Alternatively add both of them to a GeometryGroup and add that to your panel.

Upvotes: 0

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