I have to buy this full-price since I can't order book from the company anymore. Actually I ordered it from my admin 2 months ago and nothing came (テクスチャの位). Maybe they know I'm already leaving :-). That could save me $25 and now I'm $25 poorer.

Thank you.

public IInputElement InputHitTest (
Point point
)

 Passing in the coordinate, and this function will look at the element subtree and get the element (IInputElement because it's a common interface between ContentElement and UIElement) that is at that location.

double len = 0d;
Point pt, ptTan;
EllipseGeometry geo = new EllipseGeometry(new Point(50, 50), 50, 50);
PathGeometry pathGeo = geo.GetFlattenedPathGeometry();

for (int c = 0; c < 12; ++c)
{
    len += (double)(1 / 12d);
    pathGeo.GetPointAtFractionLength(len, out pt, out ptTan);
    Rectangle rect = new Rectangle();
    rect.Height = rect.Width = 2;
    rect.Fill = Brushes.Red;
    this.mainCanvas.Children.Add(rect);

    Canvas.SetTop(rect, pt.Y);
    Canvas.SetLeft(rect, pt.X);
}

PresentationSource is such a useful class after digging deeper into it. I’ve use it from time to time and looking at its members, I can see more use of it in the future.

The purpose of PresentationSource is to handle interop scenarios. To begin using this, anytime you want to call into User32.dll, you need a HWND.

Then you need this to get hwnd:
IntPtr hwnd = ((HwndSource)PresentationSource.FromVisual(uielement)).Handle; 

You can do a ton of work from a hwnd itself like calling SetWindowLong, SetParent, SetWindowRegion and hundreds more etc..

Next cool function of PresentationSource is to get HwndSource so that you can call AddHook which allows you to subclass by providing your own WndProc.

HwndSource hwndSource = PresentationSource.FromVisual(window) as HwndSource;

            hwndSource.AddHook(…);

Then you can use PresentationSource to determined, if an element is rendered. If so it must be connected to PresentationSource.

PresentationSource.FromVisual(uielement); will return a PresentationSource object if connected, null otherwise.

PresentationSource.FromVisual(uielement).RootVisual is an alternate way to get to your Root UI like a Window without walking up the visual tree.

You can use PresentationSource.AddSourceChangedHandler to determined when the element are disconnected from it’s Parent.

Finally, you can also get CompositionTarget which is another cool class by presentationSource.CompositionTarget. By using CompositionTarget, you can do stuffs like this but don’t over-do it cause it’s expensive in performance. CompositionTarget.Rendering is an alternate way to get high fidelity (animation class) rendering. Here a summary of CompositionTarget.Rendering.

The CompositionTarget.Rendering event is fired when the animation system finishes applying animation related changes.  The updated display information is then handed off to the rendering engine, which evaluates how many times per-second it can redisplay based on scene complexity and other factors.  Depending on that, it may decide to skip a particular frame produced by the animation system.  Putting it another way, the draw rate can easily be different from the rate of the CompositionTarget.Rendering events. 

More information about this feature can be found at:
https://www.microsoft.com/technet/network/p2p/pnm.mspx

In addition, it comes with a set of APIs - p2p.lib, p2p.dll and header file in p2p.h.

The answer is DependencyPropertyDescriptor. This is similar to PropertyDescriptor from WinForm.

https://msdn2.microsoft.com/en-us/library/system.componentmodel.dependencypropertydescriptor_members.aspx

For example, if you want to get notification whenever a property change but you don't own the code and you don't derive from the class and it does not expose SomethingChanged event. How can you get notification.

DependencyPropertyDescriptor dpDes = DependencyPropertyDescriptor.FromProperty(Control.BackgroundProperty);
dpDes.AddValueChanged(myElement, myEventHandler);

So whenever someone do a SetValue/ResetValue/ClearValue on myElement.Background, myEventHandler will be raised. When you are done listening to change notification, you can do RemoveValueChanged(..) to unsubscribe.

BenCon was talking about this as well :-)

What the C or C++ Programmer Needs to Know About C# and the .NET Framework

Available in XPS and PDF. https://www.charlespetzold.com/dotnet/index.html

Using the tool, I'm dragging in a Torus model and copy to XAML. Grab those Meshes and I play with brushes, textures, transforms, rotation, cameras etc.. and you got a nice looking 3D XAML :-) Finally, I got it to look like a rotating Jade ring. 

The XAML is posted at Channel9 and it looks like:

https://www.charlespetzold.com/blog/2006/12/140114.html
https://www.charlespetzold.com/blog/2006/12/160115.html
https://www.charlespetzold.com/blog/2006/12/171020.html
https://www.charlespetzold.com/blog/2006/12/220812.html
https://www.charlespetzold.com/blog/2007/01/190146.html

and finally it's coming WPF 3d book by Petzold.
https://www.charlespetzold.com/blog/2006/12/270206.html 

5-6 years ago, there's a trend to have app written in irregular window, layered window, pixel opacity or different chrome. Then came a wave of products doing just that. I think what's coming next (in my own opinion) is the application have multiple layers and 1..n layer that display 3d visuals. For example, a TV app with tv controls in another layer in a Viewport3d floating in 3d or even animating a bit :-)

can't wait for his 3d book ...