Develop Reference

Creating a Vewport3D camera in XAML is not working

I was trying to create a new Perspective Camera using C# and apply that to my XAML code, but for some reason, when I do it directly in XAML it works fine, but when I do it in C#, it does not work.
Here is the code I got from Microsoft's demonstration: (https://learn.microsoft.com/en-us/dotnet/desktop/wpf/graphics-multimedia/how-to-create-a-3-d-scene?view=netframeworkdesktop-4.8)
<Viewport3D
Name="SceneViewViewport"
Width="954"
Height="659">
<!-- Defines the camera used to view the 3D object. -->
<Viewport3D.Camera>
<PerspectiveCamera Position="0,0,2" LookDirection="0,0,-1" FieldOfView="60" />
</Viewport3D.Camera>
<!-- The ModelVisual3D children contain the 3D models -->
<Viewport3D.Children>
<!-- This ModelVisual3D defines the light cast in the scene. Without light, the 3D
object cannot be seen. Also, the direction of the lights affect shadowing. If desired,
you can create multiple lights with different colors that shine from different directions. -->
<ModelVisual3D>
<ModelVisual3D.Content>
<DirectionalLight Color="#FFFFFF" Direction="-0.612372,-0.5,-0.612372" />
</ModelVisual3D.Content>
</ModelVisual3D>
<ModelVisual3D>
<ModelVisual3D.Content>
<GeometryModel3D>
<!-- The geometry specifies the shape of the 3D plane. In this sample, a flat sheet is created. -->
<GeometryModel3D.Geometry>
<MeshGeometry3D
TriangleIndices="0,1,2 3,4,5 "
Normals="0,0,1 0,0,1 0,0,1 0,0,1 0,0,1 0,0,1 "
TextureCoordinates="0,0 1,0 1,1 1,1 0,1 0,0 "
Positions="-0.5,-0.5,0.5 0.5,-0.5,0.5 0.5,0.5,0.5 0.5,0.5,0.5 -0.5,0.5,0.5 -0.5,-0.5,0.5 " />
</GeometryModel3D.Geometry>
<!-- The material specifies the material applied to the 3D object. In this sample a linear gradient
covers the surface of the 3D object.-->
<GeometryModel3D.Material>
<MaterialGroup>
<DiffuseMaterial>
<DiffuseMaterial.Brush>
<LinearGradientBrush StartPoint="0,0.5" EndPoint="1,0.5">
<LinearGradientBrush.GradientStops>
<GradientStop Color="Yellow" Offset="0" />
<GradientStop Color="Red" Offset="0.25" />
<GradientStop Color="Blue" Offset="0.75" />
<GradientStop Color="LimeGreen" Offset="1" />
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
</DiffuseMaterial.Brush>
</DiffuseMaterial>
</MaterialGroup>
</GeometryModel3D.Material>
<!-- Apply a transform to the object. In this sample, a rotation transform is applied, rendering the
3D object rotated. -->
<GeometryModel3D.Transform>
<RotateTransform3D>
<RotateTransform3D.Rotation>
<AxisAngleRotation3D Axis="0,3,0" Angle="40" />
</RotateTransform3D.Rotation>
</RotateTransform3D>
</GeometryModel3D.Transform>
</GeometryModel3D>
</ModelVisual3D.Content>
</ModelVisual3D>
</Viewport3D.Children>
</Viewport3D>
Works fine.
Now I put the same code (C#) version, also from Microsoft's demo, and it does not work.
viewport = (Viewport3D)FindName("SceneViewViewport");
SceneViewWidth = (float)viewport.Width;
SceneViewHeight = (float)viewport.Height;
Setup();
void Setup()
{
// Declare scene objects.
Viewport3D myViewport3D = viewport;
Model3DGroup myModel3DGroup = new Model3DGroup();
GeometryModel3D myGeometryModel = new GeometryModel3D();
ModelVisual3D myModelVisual3D = new ModelVisual3D();
// Defines the camera used to view the 3D object. In order to view the 3D object,
// the camera must be positioned and pointed such that the object is within view
// of the camera.
PerspectiveCamera myPCamera = new PerspectiveCamera();
// Specify where in the 3D scene the camera is.
myPCamera.Position = new Point3D(0, 0, 2);
// Specify the direction that the camera is pointing.
myPCamera.LookDirection = new Vector3D(0, 0, -1);
// Define camera's horizontal field of view in degrees.
myPCamera.FieldOfView = 70;
// Asign the camera to the viewport
viewport.Camera = myPCamera;
// Define the lights cast in the scene. Without light, the 3D object cannot
// be seen. Note: to illuminate an object from additional directions, create
// additional lights.
DirectionalLight myDirectionalLight = new DirectionalLight();
myDirectionalLight.Color = Colors.White;
myDirectionalLight.Direction = new Vector3D(-0.61, -0.5, -0.61);
myModel3DGroup.Children.Add(myDirectionalLight);
// The geometry specifes the shape of the 3D plane. In this sample, a flat sheet
// is created.
MeshGeometry3D myMeshGeometry3D = new MeshGeometry3D();
// Create a collection of normal vectors for the MeshGeometry3D.
Vector3DCollection myNormalCollection = new Vector3DCollection();
myNormalCollection.Add(new Vector3D(0, 0, 1));
myNormalCollection.Add(new Vector3D(0, 0, 1));
myNormalCollection.Add(new Vector3D(0, 0, 1));
myNormalCollection.Add(new Vector3D(0, 0, 1));
myNormalCollection.Add(new Vector3D(0, 0, 1));
myNormalCollection.Add(new Vector3D(0, 0, 1));
myMeshGeometry3D.Normals = myNormalCollection;
// Create a collection of vertex positions for the MeshGeometry3D.
Point3DCollection myPositionCollection = new Point3DCollection();
myPositionCollection.Add(new Point3D(-0.5, -0.5, 0.5));
myPositionCollection.Add(new Point3D(0.5, -0.5, 0.5));
myPositionCollection.Add(new Point3D(0.5, 0.5, 0.5));
myPositionCollection.Add(new Point3D(0.5, 0.5, 0.5));
myPositionCollection.Add(new Point3D(-0.5, 0.5, 0.5));
myPositionCollection.Add(new Point3D(-0.5, -0.5, 0.5));
myMeshGeometry3D.Positions = myPositionCollection;
// Create a collection of texture coordinates for the MeshGeometry3D.
PointCollection myTextureCoordinatesCollection = new PointCollection();
myTextureCoordinatesCollection.Add(new Point(0, 0));
myTextureCoordinatesCollection.Add(new Point(1, 0));
myTextureCoordinatesCollection.Add(new Point(1, 1));
myTextureCoordinatesCollection.Add(new Point(1, 1));
myTextureCoordinatesCollection.Add(new Point(0, 1));
myTextureCoordinatesCollection.Add(new Point(0, 0));
myMeshGeometry3D.TextureCoordinates = myTextureCoordinatesCollection;
// Create a collection of triangle indices for the MeshGeometry3D.
Int32Collection myTriangleIndicesCollection = new Int32Collection();
myTriangleIndicesCollection.Add(0);
myTriangleIndicesCollection.Add(1);
myTriangleIndicesCollection.Add(2);
myTriangleIndicesCollection.Add(3);
myTriangleIndicesCollection.Add(4);
myTriangleIndicesCollection.Add(5);
myMeshGeometry3D.TriangleIndices = myTriangleIndicesCollection;
// Apply the mesh to the geometry model.
myGeometryModel.Geometry = myMeshGeometry3D;
// The material specifies the material applied to the 3D object. In this sample a
// linear gradient covers the surface of the 3D object.
// Create a horizontal linear gradient with four stops.
LinearGradientBrush myHorizontalGradient = new LinearGradientBrush();
myHorizontalGradient.StartPoint = new Point(0, 0.5);
myHorizontalGradient.EndPoint = new Point(1, 0.5);
myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.Yellow, 0.0));
myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.Red, 0.25));
myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.Blue, 0.75));
myHorizontalGradient.GradientStops.Add(new GradientStop(Colors.LimeGreen, 1.0));
// Define material and apply to the mesh geometries.
DiffuseMaterial myMaterial = new DiffuseMaterial(myHorizontalGradient);
myGeometryModel.Material = myMaterial;
// Apply a transform to the object. In this sample, a rotation transform is applied,
// rendering the 3D object rotated.
RotateTransform3D myRotateTransform3D = new RotateTransform3D();
AxisAngleRotation3D myAxisAngleRotation3d = new AxisAngleRotation3D();
myAxisAngleRotation3d.Axis = new Vector3D(0, 3, 0);
myAxisAngleRotation3d.Angle = 40;
myRotateTransform3D.Rotation = myAxisAngleRotation3d;
myGeometryModel.Transform = myRotateTransform3D;
// Add the geometry model to the model group.
myModel3DGroup.Children.Add(myGeometryModel);
// Add the group of models to the ModelVisual3d.
myModelVisual3D.Content = myModel3DGroup;
//
myViewport3D.Children.Add(myModelVisual3D);
// Apply the viewport to the page so it will be rendered.
this.Content = myViewport3D;
}
I tried using Microsoft's example, found here: "https://learn.microsoft.com/en-us/dotnet/desktop/wpf/graphics-multimedia/how-to-create-a-3-d-scene?view=netframeworkdesktop-4.8", but nothing changed. The XAML version works as expected, but the C# version only displays an empty screen.

How to create brick pattern in WPF in code? [duplicate]

This question already has answers here:
Creating Diagonal Pattern in WPF
(3 answers)
Create a hatch pattern in WPF
(2 answers)
Shape with slanted lines as background
(2 answers)
Create stripe brush in WPF
(2 answers)
Closed 3 years ago.
This question is similar to others, but my research has not uncovered the answer I seek. I am trying to fill a rectangle with a brick pattern. I understand there is not a HatchBrush in WPF and if there was perhaps I would do this: HatchBrush brush = new HatchBrush(HatchStyle.DiagonalBrick,System.Drawing.Color.Black); But since there is not I am using a DrawingBrush as follows, which fills the rectangle with a darkblue solid color. Where do I specify the DiagonalBrick?
Rectangle fillRect = new Rectangle();
//Try to fill fillRect with a pattern
Rect aRect = new Rect();
aRect.Width = fillRect.Width;
aRect.Height = fillRect.Height;
GeometryGroup rectangle = new GeometryGroup();
GeometryDrawing geomDrawing = new GeometryDrawing(Brushes.DarkBlue,null, rectangle);
DrawingBrush drawingBrush = new DrawingBrush();
rectangle.Children.Add(new RectangleGeometry(aRect, 0, 0));
geomDrawing.Geometry = rectangle;
drawingBrush.Drawing = geomDrawing;
fillRect.Fill = drawingBrush;

There's actually quite a few different ways to do this, but based on the code you've posted I'll assume you want to create your own geometry, using pixels as your coordinate system, and use that to paint a rectangle. This is one of those cases where WPF's flexibility means you have to be a lot more verbose than you would in previous platforms, but let's work through it...
The brick pattern can be achieved by creating a DrawingBrush containing a GeometryDrawing. The trick is to create two bricks of size <60,40> that are offset:
The problem now is the black background poking through. We can solve that by placing a third brick to the left of the one on the bottom, and then setting the DrawBrush's Viewport and Viewbox to the rectangle <0,0,60,80>, and then setting TileMode to "Tile". The code to do this is as follows:
var brickBrush = new DrawingBrush
{
Viewport = new Rect(0, 0, 60, 80),
ViewportUnits = BrushMappingMode.Absolute,
Viewbox = new Rect(0, 0, 60, 80),
ViewboxUnits = BrushMappingMode.Absolute,
TileMode = TileMode.Tile,
Drawing = new GeometryDrawing
{
Brush = new SolidColorBrush(Color.FromRgb(0xB1, 0x78, 0x33)),
Geometry = new GeometryGroup
{
Children = new GeometryCollection(new Geometry[] {
new RectangleGeometry(new Rect( 0, 0, 60, 40)),
new RectangleGeometry(new Rect( 30, 40, 60, 40)),
new RectangleGeometry(new Rect(-30, 40, 60, 40))
}),
},
Pen = new Pen(new SolidColorBrush(Color.FromRgb(0xE1, 0xD7, 0xBD)), 5)
}
};
theRectangle.Fill = brickBrush;
Which will generate the following pattern:
As your WPF skill improves you'll eventually want to start doing stuff like this in XAML. For the purpose of comparison, here is the code needed to achieve the same fill:
<Window.Resources>
<DrawingBrush x:Key="BrickBrush" Viewport="0,0,60,80" ViewportUnits="Absolute" Viewbox="0,0,60,80" ViewboxUnits="Absolute" TileMode="Tile">
<DrawingBrush.Drawing>
<GeometryDrawing Brush="#B17833">
<GeometryDrawing.Geometry>
<GeometryGroup>
<RectangleGeometry Rect="0,0,60,40" />
<RectangleGeometry Rect="30,40,60,40" />
<RectangleGeometry Rect="-30,40,60,40" />
</GeometryGroup>
</GeometryDrawing.Geometry>
<GeometryDrawing.Pen>
<Pen Thickness="5" Brush="#E1D7BD" />
</GeometryDrawing.Pen>
</GeometryDrawing>
</DrawingBrush.Drawing>
</DrawingBrush>
</Window.Resources>
<Rectangle Fill="{StaticResource BrickBrush}" />
You've also alluded to wanting diagonal bricks, to do that you simply add a rotation transform to the DrawingBrush:
var brickBrush = new DrawingBrush
{
Transform = new RotateTransform(45),
... etc ...

How can you outline an ellipse without using stroke property?

What I really want is a way to have a negative stroke Thickness value on a WPF shape such as an ellipse, so that the stoke outline paints outwards towards LEFT and TOP of Shape, rather than inside of the shape, over writing my text when I make the thinkness of the stroke too thick... I want the radius of my ellipse to stay constant, but the stroke to grow outwards with increased thinkness, and the LEFT, TOP placement of the shape to remain contant with the inner fill staying the same size and not getting covered up by stroke as it is increased in size.
I tried DropShadowEffect, but its kind of too blurry and not well defined enough...and looks kind of messy... really I just want a solid line going around the outside of the shape...
As you can see from attached picture above, I tried to put shadow around two the ellipses using this code below. the problem is that I want it to be a solid color around the outside like a scaletransform of another ellipse of a different color.
var e = new Ellipse();
DropShadowEffect effect = new DropShadowEffect();
effect.Color =Colors.Orange;
effect.Direction = 0;
effect.BlurRadius = 30;
effect.ShadowDepth = 4;
effect.Opacity=0;
e.Effect = effect;
t.Text = string.Format("abc");
t.Measure(new Size(gwin.XStep, gwin.YStep));
t.Arrange(new Rect(t.DesiredSize));
e.StrokeThickness = 2;
e.Stroke = Brushes.Black;
canvas.Children.Add(e);
canvas.Children.Add(t);
Another possible direction towards solving the problem:
<Ellipse RenderTransformOrigin="0.5,0.5">
<Ellipse.RenderTransform>
<TransformGroup>
<ScaleTransform/>
</TransformGroup>
</Ellipse.RenderTransform>
</Ellipse>
Convert to c# code and place one scaletransform ellipse centered inside another scaled transform ellipse of different colors... not sure how to set it up though.
Solution:
Based on suggestion below. I tried creating a grid, setting the width and height of the grid to the size of my ellipse, then adding two ellipses to the grid with different colors and one with a margin set to -10. and it works perfectly ... just need to place the larger ellipse with margin -10 behind the other ellipse when adding it to the grid...here's what it looks like now..
Solution is in here somewhere:
g = new Grid();
e = new Ellipse();
h = new Ellipse();
t = new TextBlock();
t.HorizontalAlignment = HorizontalAlignment.Center;
t.VerticalAlignment = VerticalAlignment.Center;
t.FontWeight = FontWeights.ExtraBold;
g.Children.Add(h);
g.Children.Add(e);
g.Children.Add(t);
gwin.canvas.Children.Add(g);
t.Text = String.Format("{0}.{1}", x, y);
g.Width = gwin.XStep;
g.Height = gwin.YStep;
Canvas.SetLeft (g, gwin.X1 + gwin.XStep*x*2);
Canvas.SetTop (g, gwin.Y1 + gwin.YStep*y*2);
e.StrokeThickness = 2;
e.Stroke = Brushes.Black;
h.Margin = new Thickness(-10);

You can use double ellipses inside a grid overlaying each other like this:
<Grid Width="100" Height="100">
<Ellipse Fill="Black" Margin="-10"/>
<Ellipse Fill="Red" />
</Grid>
The size of this compound is still 100x100 even though the first ellipse is bigger and rendered out of its boundaries.
You may also use a Path and then do this

I think there is something like border. Or you can draw one elipse and then a second one in smaller that has the background color.

How to draw gridline on WPF Canvas?

I need to build a function drawing gridline on the canvas in WPF:
void DrawGridLine(double startX, double startY, double stepX, double stepY,
double slop, double width, double height)
{
// How to implement draw gridline here?
}
How would I go about this?

You don't really have to "draw" anything with WPF. If you want to draw lines, use the appropriate geometries to draw them.
In your case it could be simple really. You're just drawing a grid so you could just create a DrawingBrush to draw a single grid square and tile it to fill in the rest. To draw your tile, you could think of it as drawing X's. So to have a 20x10 tile (which corresponds to stepX and stepY):
(p.s., the slope slop is redundant since you already have the horizontal and vertical step sizes)
<DrawingBrush x:Key="GridTile" Stretch="None" TileMode="Tile"
Viewport="0,0 20,10" ViewportUnits="Absolute">
<!-- ^^^^^^^^^^^ set the size of the tile-->
<DrawingBrush.Drawing>
<GeometryDrawing>
<GeometryDrawing.Geometry>
<!-- draw a single X -->
<GeometryGroup>
<!-- top-left to bottom-right -->
<LineGeometry StartPoint="0,0" EndPoint="20,10" />
<!-- bottom-left to top-right -->
<LineGeometry StartPoint="0,10" EndPoint="20,0" />
</GeometryGroup>
</GeometryDrawing.Geometry>
<GeometryDrawing.Pen>
<!-- set color and thickness of lines -->
<Pen Thickness="1" Brush="Black" />
</GeometryDrawing.Pen>
</GeometryDrawing>
</DrawingBrush.Drawing>
</DrawingBrush>
That takes care of drawing the lines. Now to be able to draw them offset in your grid from the edges, you need to have another brush where you draw a rectangle with the desired dimensions, filled with your tiles. So to have a starting position of (30, 45) (corresponding to startX and startY) with the width and height, 130x120:
<DrawingBrush x:Key="OffsetGrid" Stretch="None" AlignmentX="Left" AlignmentY="Top">
<DrawingBrush.Transform>
<!-- set the left and top offsets -->
<TranslateTransform X="30" Y="45" />
</DrawingBrush.Transform>
<DrawingBrush.Drawing>
<GeometryDrawing Brush="{StaticResource GridTile}" >
<GeometryDrawing.Geometry>
<!-- set the width and height filled with the tile from the origin -->
<RectangleGeometry Rect="0,0 130,120" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingBrush.Drawing>
</DrawingBrush>
Then finally to use it, just set it as the background of your grid (or other panel):
<Grid Background="{StaticResource OffsetGrid}">
<!-- ... -->
</Grid>
Here's how it ends up looking like:
If you want to generate the brush dynamically, here's an equivalent function based on the above XAML:
static Brush CreateGridBrush(Rect bounds, Size tileSize)
{
var gridColor = Brushes.Black;
var gridThickness = 1.0;
var tileRect = new Rect(tileSize);
var gridTile = new DrawingBrush
{
Stretch = Stretch.None,
TileMode = TileMode.Tile,
Viewport = tileRect,
ViewportUnits = BrushMappingMode.Absolute,
Drawing = new GeometryDrawing
{
Pen = new Pen(gridColor, gridThickness),
Geometry = new GeometryGroup
{
Children = new GeometryCollection
{
new LineGeometry(tileRect.TopLeft, tileRect.BottomRight),
new LineGeometry(tileRect.BottomLeft, tileRect.TopRight)
}
}
}
};
var offsetGrid = new DrawingBrush
{
Stretch = Stretch.None,
AlignmentX = AlignmentX.Left,
AlignmentY = AlignmentY.Top,
Transform = new TranslateTransform(bounds.Left, bounds.Top),
Drawing = new GeometryDrawing
{
Geometry = new RectangleGeometry(new Rect(bounds.Size)),
Brush = gridTile
}
};
return offsetGrid;
}

WPF: the right way to scale a path?

I have a path (looks like an oval):
<Path Data="Bla Bla"/>
Now I want to scale the path's width and height to whatever I like. I found a way:
<Grid Width="400" Height="50">
<Viewbox Stretch="Fill">
<Path Data="Bla Bla"/>
</Viewbox>
</Grid>
And this works, but I'm wondering if this is the most efficient way to do this? (I had to introduce a grid and viewbox to do this)

Another way to Scale a Path is to use RenderTransform or LayoutTransform
<Path Data="Bla Bla"
RenderTransformOrigin="0.5, 0.5">
<Path.RenderTransform>
<ScaleTransform ScaleX="1.5" ScaleY="1.5"/>
</Path.RenderTransform>
</Path>

just FYI, since ViewBox uses ScaleTransform inside it it's basically just as good performance-wise.

You basically have 3 ways to scale a Path:
Wrap it into a ViewBox
Apply a ScaleTransform
Explicitly set a Width and a Height
Method 1. and 2. will yield the same result, while 3. is slightly different because the shape will change size, but the stroke will keep the original Thickness (so it's not really a zoom).
Method 1. would be appropriate when you have an area of a given size that you want to fill. On the other hand method 2. will be useful to enlarge (or reduce) the path by a given amount, for ex. two times the original size.

You could do it programmaticaly, like
http://social.msdn.microsoft.com/Forums/vstudio/en-US/a0d473fe-3235-4725-aa24-1ea9307752d3/how-to-rendertransform-in-code-behind-c?forum=wpf
kUIWEB:kArrow mArrow = new kUIWEB:kArrow();
mArrow.Width=30;
mArrow.Height=30;
mArrow.RenderTransformOrigin=new Point(0.5, 0.5);
ScaleTransform myScaleTransform = new ScaleTransform();
myScaleTransform.ScaleY = 1;
myScaleTransform.ScaleX = 1;
RotateTransform myRotateTransform = new RotateTransform();
myRotateTransform.Angle = 0;
TranslateTransform myTranslate = new TranslateTransform ();
myTranslate.X = 12;
myTranslate.X = 15;
SkewTransform mySkew = new SkewTransform ();
mySkew.AngleX=0;
mySkew.AngleY=0;
// Create a TransformGroup to contain the transforms
// and add the transforms to it.
TransformGroup myTransformGroup = new TransformGroup();
myTransformGroup.Children.Add(myScaleTransform);
myTransformGroup.Children.Add(myRotateTransform);
myTransformGroup.Children.Add(myTranslate);
myTransformGroup.Children.Add(mySkew);
// Associate the transforms to the object
mArrow.RenderTransform = myTransformGroup;