I've got an array of points (X,Y) which constitute a convex hull (a simple, irregularly shaped contour). Rather than rendering a polygon with straight edges, I want to render them with an approximate "smoothly curved" contour that passes through all of these points.
In WinForms/GDI+, this could be accomplished with the Graphics.DrawClosedCurve or Graphics.FillClosedCurve methods. There does not appear to be an equivalent in WPF.
I've looked into drawing using things like Path and BezierSegment, but I'm not sure if (and how) these can be used to generate a continuous closed curve, given a set of points. It appears that to do this, I'd perhaps have to generate a set of control points based on my contour as an intermediate step?
I have tried using the GDI+ methods to render onto a System.Drawing.Bitmap and then displaying that in the WPF application. This works, but the performance (particularly the conversion from System.Drawing.Bitmap to BitmapSource) is poor and not sufficient for the application. This is why I'm looking for a pure WPF solution.
Has anyone been able to draw a closed curve based off a set of points in WPF?
Unfortunately, there is no single-method equivalent to DrawClosedCurve in WPF, even though it's been requested. So you are left with at least two options:
Host a native window within your WPF window and perform all your drawing on it.
Implement your own cardinal spline drawing. You are on the right track with Bezier segments. However, there are existing implementations of it you can look at out there.
Related
Is it possible to implement per-pixel-lighting in WPF 3d application (C#) by using their shader effects?
I have a basic 3d application running in WPF but it only shows Gouraud Shading, by interpolating shaded colour values between vertices to the inner of the polygons. I tried to implement a per-pixel lighting approach, like Phong, but I realize that I do not seem to have access to interpolated normals in the WPF pixel shader effects.
Is this the limitation of WPF, where one should better go with C++ and OpenGL/DirectX directly?
as far as I know, yes it is a WPF limitation...contrary to the OpenGL where you can do per-pixel shading, the WPF only allows you to work on a meshGeometry.
I think a way to go with it, would be to create textures that contains your shader effect, and then apply it per triangle.
This would take a longer amount of computation time, but should work.
Regards
I am developing my system using WPF with MVVM and I am having trouble to find out the best way to solve the following problem:
I have a screen in which many components (User Controls) are drawn at specific positions. All components in the screen are rotated, translated and scaled according to binded variables calculated by the screen's VM.
However, each of this components could have a different center for the rotation, a different origin for the translation and a different scale, dependent of internal variables and the screen scale.
How is it possible to make this transformations calculated internally in the User Control? I think the easier approach is using the Converter, however since I have many different User Controls with different behaviours, I would have to create multiple converters very similar to each other, which would not be the ideal solution.
Thank you very much for the help!
A UIElement has only one RenderTransformOrigin.
Some transformations allow you to set the origin for that transformation but in coordinates relative to the control bounds (e.g.: 125, 34) not in proportional coordinates like the RenderOrigin (e.g.: 0.5, 0.75)
So if you can use the coordinates you're good to go.
If not, you could compose the transformations by creating Transformation groups that first translate the control, then perform the transformation, and then translate the control back.
If you need more help, please post an example of what you are trying to achieve.
I'm trying to write an CAD-like application in WPF(.NET 4.0) that needs to be able to display a lot of 2D points/lines. It will be used to display CAD-plans of entire cities with zoom, pan, rotate and point snapping on mouseover.
Right now I purely use WPF. I read the objects from the CAD file draw them into a StreamGeometry, use it as stroke of a new Path and add it to a Canvas, with several transforms.
My problem is that this solution doesn't scale well enough. It works fine with small CAD-files, but when I want to display like half a city(with houses and land boundaries) it is very very delayed.
I also tried to convert my CAD-file to an image, but
- a resolution a 32000x32000 is sometimes not enough
- when zooming out the lines are too thin.
In the end I need to be able to place this on a Canvas(2D/3D) as background.
What are my best options here?
Thanks,
Niklas
wpf is not good for a large 3d models. im afraid it is too slow. Your best bet is direct 3d or openGL
However, even with the speed of direct3d,openGL you will still need to work out how to cull as many polygons/vertices as possible before the rendering of the scene if you are trying to show an entire city.
there is a large amount of information on this (generally under game development)
there are a few techniques including frustrum culling, near and far plane culling.
also, since you probably have a static scene you may be able to use binary spacial partitioning.
As I understand the subject is 2D CAD system within WPF.
Great! I use it...
OpenGL and DirectX are in infinite loop OnDraw always. The CPU works all the time.
WPF/Silverlight 2D is smart model.
Yes, total amount of elements (for example, primitives inherited from Shape) must be not so much. But how many?
I tested own app (Silverlight). WPF will be a bit faster I hope...
Here my 2D CAD results. Performance is still great. Each beam consists of multiple primitives.
Use a VirtualCanvas like this one from Chris Lovett.
Now that <BevelBitmapEffect> (amongst other effects) has been depreciated, I'm looking to see how I could re-create the exact same thing in a Shader Effect (including it's properties of BevelWidth, EdgeProfile, LightAngle, Relief and Smoothness).
I'm somewhat familar with pixel shading, mostly just colors manipulation of the whole image/element in Shazzam, but how to create a bevel elludes me. Is this a vertex shader and if so, how would I get started? I have searched high and low on this but can't seem to find an inkling of information that would allow me to get started in reproducing <BevelBitmapEffect> in a custom Effect.
Or, based on a comment below, is this 3D in WPF and if so, are there code libraries out there for recreating a <BevelBitmapEffect> that mimics the one that came with previous versions of WPF?
To create the bevel you need to know the distance from the edge for each pixel (search in all directions until alpha=0). From this you can calculate the normal then shade it (see silverlight example). As you mentioned there isn't much content about bevels but there are some good resources if you search for bump mapping/normal mapping to which the shading is similar. In particular this thread has a Silverlight example using a pre-calculated normal map.
To do everything in hardware ideally you would use a multipass shader, WPF's built-in effects are multipass but it doesn't allow you to write your own.
To workaround this limitation:
You could create multiple shaders and nest your element in multiple controls applying a different effect to each one.
Target WPF 4.0 and use Pixel Shader 3.0, for the increased instruction count. Although this may be a too high a hardware requirement and there is no software fallback for PS 3.0
Do some or all of the steps in software.
Without doing one of these you'd be lucky to do a 3 or 4 pixel bevel before you reach the instruction limit as the loops needed to find the distance increase the instruction count quickly.
New Sample
Download. Here is an example that uses PixelShader 3.0. It uses one shader to find the distance (aka height) to the edge, another (based on the nvidia phong shaders) is used to shade it. Bevel profiles are created by adjusting input height either with code or a custom profile can be used by supplying a special texture. There are some other features to add but it seems easily performant enough to animate the properties. Its lacking in comments but I can explain parts if needed.
There's a great article by Rod Stephens on DevX that shows how to use System.Drawing to create the WPF effects (the ones that used to exist, such as Bevel) and more. You've gotta register to view the article though, it's at http://www.devx.com/DevXNet/Article/45039. Downloadable source code too.
I need to write a simple WPF program to draw a Bezier curve, but I have to draw it programmatically since I need to allow user to modify the shape interactively.
Any code sample to do this task is highly appreciated!
Thanks,
Mike
Have a look at the Path Markup Syntax to get a feel for the raw drawing primitives available to you in WPF.
You could use either cubic or quadratic Bezier curves (each has a smoothed version too) depending on how you want to define the control points.
As for rendering the control points on screen and allowing the user to drag them about you might like to look into adorners and possibly the Thumb class.