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How can I draw an arc in C# WPF with parameters?

I would like to know how can I draw an arc in C# , I'm trying using DrawEllipse but it doesn't work and it give wrong drawing.
However, I have searched for a method to draw an arc in the Class DrawingContext but I didn't find it.
DrawingVisual d = new DrawingVisual();
System.Windows.Media.Pen pen = new System.Windows.Media.Pen();
DrawingContext drawingContext = d.RenderOpen();
pen.Brush = System.Windows.Media.Brushes.Black;
System.Windows.Point center = new System.Windows.Point();
center.X = 0.4;
center.Y = 0.5;
drawingContext.DrawEllipse(System.Windows.Media.Brushes.White, pen, center, 4,4);
drawingContext.Close();
canvas.Children.Add(new VisualHost { Visual = d });

You would have to draw a PathGeometry or a StreamGeometry that contains an arc segment, like the following circular arc of radius 100 from (100,100) to (200,200):
var visual = new DrawingVisual();
var pen = new Pen(Brushes.Black, 1);
using (var dc = visual.RenderOpen())
{
var figure = new PathFigure
{
StartPoint = new Point(100, 100) // start point
};
figure.Segments.Add(new ArcSegment
{
Point = new Point(200, 200), // end point
Size = new Size(100, 100), // radii
SweepDirection = SweepDirection.Clockwise
});
var geometry = new PathGeometry();
geometry.Figures.Add(figure);
dc.DrawGeometry(null, pen, geometry);
}

Is there any way to draw 2D shapes in Viewport3D like arc, line, point and plane?

Right now I am using Viewport3D in which I am drawing all 3D shapes but I also want to draw arc, point and lines in Viewport3D. Can anyone help me with this?
private Viewport2DVisual3D ArcModel;
private Model3DGroup group;
MeshGeometry3D testGeometry = new MeshGeometry3D();
PathFigure pthFigure = new PathFigure();
pthFigure.StartPoint = new Point(1, 1);
ArcSegment arcSeg = new ArcSegment();
arcSeg.Point = new Point(30, 30);
arcSeg.Size = new Size(20, 20);
arcSeg.IsLargeArc = true;
arcSeg.SweepDirection = SweepDirection.Counterclockwise;
//arcSeg.RotationAngle = 30;
PathSegmentCollection myPathSegmentCollection = new PathSegmentCollection();
myPathSegmentCollection.Add(arcSeg);
pthFigure.Segments = myPathSegmentCollection;
PathFigureCollection pthFigureCollection = new PathFigureCollection();
pthFigureCollection.Add(pthFigure);
PathGeometry pthGeometry = new PathGeometry();
pthGeometry.Figures = pthFigureCollection;
Path arcPath = new Path();
arcPath.Stroke = new SolidColorBrush(Colors.Violet);
arcPath.StrokeThickness = 1;
arcPath.Data = pthGeometry;
//arcPath.Fill = new SolidColorBrush(Colors.Yellow);
//Children.Add(arcPath);
Point3DCollection myPoint3DCollection = new Point3DCollection();
myPoint3DCollection.Add(new Point3D(0, 0, 0));
myPoint3DCollection.Add(new Point3D(0, 0, 2));
myPoint3DCollection.Add(new Point3D(0, 2, 0));
myPoint3DCollection.Add(new Point3D(0, 2, 2));
testGeometry.Positions = myPoint3DCollection;
PointCollection myPointCollection = new PointCollection();
myPointCollection.Add(new Point(0, 1));
myPointCollection.Add(new Point(1, 1));
myPointCollection.Add(new Point(0, 0));
myPointCollection.Add(new Point(1, 0));
testGeometry.TextureCoordinates = myPointCollection;
Int32Collection triangleIndicesCollection = new Int32Collection();
triangleIndicesCollection.Add(0);
triangleIndicesCollection.Add(1);
triangleIndicesCollection.Add(2);
triangleIndicesCollection.Add(2);
triangleIndicesCollection.Add(1);
triangleIndicesCollection.Add(3);
testGeometry.TriangleIndices = triangleIndicesCollection;
DiffuseMaterial myDiffuseMaterial = new DiffuseMaterial(Brushes.White);
Viewport2DVisual3D.SetIsVisualHostMaterial(myDiffuseMaterial, true);
ArcModel = new Viewport2DVisual3D();
ArcModel.Material = myDiffuseMaterial;
ArcModel.Geometry = testGeometry;
//group.Children.Add(ArcModel.Geometry);
ArcModel.Visual = arcPath;
ArcGeomodel = new GeometryModel3D(ArcModel.Geometry, myDiffuseMaterial);
ArcGeomodel.Transform = new Transform3DGroup();
group.Children.Add(ArcGeomodel);
viewport.Children.Add(ArcModel);
I am drawing this arc using path geometry and adding it into Viewport2DVisual3D but its not getting displayed...
what I am missing here ...please suggest any solution

Finally got what I was missing.I was missing to add transformation and rotation to it
following is the code
Transform3DGroup myTransform3DGroup = new Transform3DGroup();
RotateTransform3D rotateTransform = new RotateTransform3D()
{
Rotation = new AxisAngleRotation3D
{
Angle = 40,
Axis = new Vector3D(0, 1, 0)
}
};
myTransform3DGroup.Children.Add(rotateTransform);
ArcModel.Transform = myTransform3DGroup;
ArcModel.Material = myDiffuseMaterial;
ArcModel.Geometry = testGeometry;
ArcModel.Visual = arcPath;
viewport.Children.Add(ArcModel);
Hope this will help someone!

Using RenderedGeometry as Data of Path does not work

I want to draw a simple Path which uses RenderedGeometry of a Polygon as Data.
Polygon polygon = new Polygon();
polygon.Points = new PointCollection { new Point(0, 0), new Point(0, 100), new Point(150, 150) };
var path = new Path
{
Data = polygon.RenderedGeometry,
Stroke = Brushes.LightBlue,
StrokeThickness = 2,
Fill = Brushes.Green,
Opacity = 0.5
};
Panel.SetZIndex(path, 2);
canvas.Children.Add(path);
However my Canvas does not display anything.

You should force the geometry to be rendered before you it to the Canvas. You can do this by calling the Arrange and Measure methods of the Polygon:
Polygon polygon = new Polygon();
polygon.Points = new PointCollection { new Point(0, 0), new Point(0, 100), new Point(150, 150) };
polygon.Arrange(new Rect(canvas.RenderSize));
polygon.Measure(canvas.RenderSize);
var path = new Path
{
Data = polygon.RenderedGeometry,
Stroke = Brushes.LightBlue,
StrokeThickness = 2,
Fill = Brushes.Green,
Opacity = 0.5
};
Panel.SetZIndex(path, 2);
canvas.Children.Add(path);

You shouldn't be using a Polygon element to define the Geometry of a Path.
Instead directly create a PathGeometry like this:
var figure = new PathFigure
{
StartPoint = new Point(0, 0),
IsClosed = true
};
figure.Segments.Add(new PolyLineSegment
{
Points = new PointCollection { new Point(0, 100), new Point(150, 150) },
IsStroked = true
});
var geometry = new PathGeometry();
geometry.Figures.Add(figure);
var path = new Path
{
Data = geometry,
Stroke = Brushes.LightBlue,
StrokeThickness = 2,
Fill = Brushes.Green,
Opacity = 0.5
};
Or directly create a Geometry from a string using Path Markup Syntax:
var path = new Path
{
Data = Geometry.Parse("M0,0 L0,100 150,150Z"),
Stroke = Brushes.LightBlue,
StrokeThickness = 2,
Fill = Brushes.Green,
Opacity = 0.5
};

Connect two UIElement with Arc

I have two UIElements(i.e. rectangles) in Canvas and their coordinates. How can I connect them with arc in code behind?

No need to get an exact hit on the rectangles (or other objects): make sure the Z ordering is correct. arc.SetValue(Canvas.ZIndex, -1) will push it to the background. If you want a perpendicular hit, you'll need to break out the algebra :/
For the arc: (see http://msdn.microsoft.com/en-us/library/ms751808.aspx), it needs to be contained in a PathFigure.
Edit: this shows two connected rectangles. The line simple runs between the two centers. The arc starts on one center (the pathFigure startpoint), first argument is the center of the second object.
r1 = new Rectangle();
r1.Margin = new Thickness(50, 50, 0, 0);
r1.VerticalAlignment = System.Windows.VerticalAlignment.Top;
r1.HorizontalAlignment = System.Windows.HorizontalAlignment.Left;
r1.Height = 50;
r1.Width= 50;
r1.Fill = new SolidColorBrush(Colors.Red);
r2 = new Rectangle();
r2.Width = 50;
r2.Height = 50;
r2.Fill = new SolidColorBrush(Colors.Blue);
r2.Margin = new Thickness(350, 450, 0, 0);
r2.VerticalAlignment = System.Windows.VerticalAlignment.Top;
r2.HorizontalAlignment = System.Windows.HorizontalAlignment.Left;
l = new Line();
l.X1 = 75;
l.Y1 = 75;
l.X2 = 375;
l.Y2 = 475;
l.Fill = new SolidColorBrush(Colors.Purple);
l.Stroke = new SolidColorBrush(Colors.Purple);
l.StrokeThickness = 2;
l.SetValue(Canvas.ZIndexProperty, -1);
PathGeometry myPathGeometry = new PathGeometry();
// Create a figure.
PathFigure pathFigure1 = new PathFigure();
pathFigure1.StartPoint = new Point(75, 75);
pathFigure1.Segments.Add(
new ArcSegment(
new Point(375, 475),
new Size(50, 50),
45,
true, /* IsLargeArc */
SweepDirection.Clockwise,
true /* IsStroked */ ));
myPathGeometry.Figures.Add(pathFigure1);
// Display the PathGeometry.
Path myPath = new Path();
myPath.Stroke = Brushes.Black;
myPath.StrokeThickness = 1;
myPath.Data = myPathGeometry;
myPath.SetValue(Canvas.ZIndexProperty, -1);
LayoutRoot.Children.Add(r1);
LayoutRoot.Children.Add(r2);
LayoutRoot.Children.Add(l);
LayoutRoot.Children.Add(myPath);

create polygon filled up with dots

Am using the below code to create polygon. i just want to fill this polygon surface with black dots, how i can do that, then i want to convert this polygon to bitmap or in memory stream, how to do this??
// Create a blue and a black Brush
SolidColorBrush yellowBrush = new SolidColorBrush();
yellowBrush.Color = Colors.Transparent;
SolidColorBrush blackBrush = new SolidColorBrush();
blackBrush.Color = Colors.Black;
// Create a Polygon
Polygon yellowPolygon = new Polygon();
yellowPolygon.Stroke = blackBrush;
yellowPolygon.Fill = yellowBrush;
yellowPolygon.StrokeThickness = 4;
// Create a collection of points for a polygon
System.Windows.Point Point1 = new System.Windows.Point(50, 100);
System.Windows.Point Point2 = new System.Windows.Point(200, 100);
System.Windows.Point Point3 = new System.Windows.Point(200, 200);
System.Windows.Point Point4 = new System.Windows.Point(300, 30);
PointCollection polygonPoints = new PointCollection();
polygonPoints.Add(Point1);
polygonPoints.Add(Point2);
polygonPoints.Add(Point3);
polygonPoints.Add(Point4);
// Set Polygon.Points properties
yellowPolygon.Points = polygonPoints;
// Add Polygon to the page
mygrid.Children.Add(yellowPolygon);

Do the dots have to be positioned in a particular order or do you just want to have a dotted pattern in your polygon without specific order?
If you don't need a special order you could use a Brush, a DrawingBrush for instance. Check out this link: http://msdn.microsoft.com/en-us/library/aa970904.aspx
You can then set this Brush as the Fill-Property of your Polygon instead of the SolidColorBrush.
This is the DrawingBrush example from the msdn link, but modified to display dots:
// Create a DrawingBrush and use it to
// paint the rectangle.
DrawingBrush myBrush = new DrawingBrush();
GeometryDrawing backgroundSquare =
new GeometryDrawing(
Brushes.Yellow,
null,
new RectangleGeometry(new Rect(0, 0, 100, 100)));
GeometryGroup aGeometryGroup = new GeometryGroup();
aGeometryGroup.Children.Add(new EllipseGeometry(new Rect(0, 0, 20, 20)));
SolidColorBrush checkerBrush = new SolidColorBrush(Colors.Black);
GeometryDrawing checkers = new GeometryDrawing(checkerBrush, null, aGeometryGroup);
DrawingGroup checkersDrawingGroup = new DrawingGroup();
checkersDrawingGroup.Children.Add(backgroundSquare);
checkersDrawingGroup.Children.Add(checkers);
myBrush.Drawing = checkersDrawingGroup;
myBrush.Viewport = new Rect(0, 0, 0.05, 0.05);
myBrush.TileMode = TileMode.Tile;
yellowPolygon.Fill = myBrush;