I have some 3D Geometry that resembles a wheel. I want to be able to rotate it but in a controllable way. I have a slider and I want to change the speed of the wheel's rotation according to the slider value without having to stop it. What is the best way to achieve that.
I know how to rotate it to a certain degree and I also know how to have some continuous Storyboard that rotates the wheel. But I don't know how to change that according to the slider's value.
After playing a lot with it, I did it. This is how:
Created a Storyboard with a "Forever" RepeatBehavior
In my code, as I receive info from USB -not from a slider anymore- I change the Storyboard's SpeedRatio accordingly (You can also bind it to a slider progress or whatever else)
Related
So I realize that I am venturing outside of the intended use of a Canvas here and will likely have to come up with a more manual solution. However, not being overly experienced in WPF I was hoping that there may be some solution which would allow me to continue using a Canvas control and the features it gives you for free.
The issue revolves around a Canvas which is used to zoom in and out of an image and some number of child controls that belong to the Canvas. These child controls are to be placed at various positions on the image and, as such, the Canvas works nicely in that it handles all of the layout/positioning for me as I zoom in or out.
However, one drawback is that the Canvas scales these child controls up as I zoom into the image, causing them to become too large to be usable in practice. What I am looking for is a solution that allows me to zoom into an image that belongs to a canvas without also zooming up the size of the child controls, preferably handling the layout for me.
I have tried modifying the width and height of these child controls as the zoom factor increases or decreases, but there is a slight lag time and it all looks a bit 'jerky'.
If it comes down to it I will simply do all of the zooming/panning/layout myself, but I thought I would ask first just to make sure that I am not missing anything that would allow me to tell the Canvas to not scale the size of certain controls. Thanks in advance.
You can bind the children's RenderTransform to the inverse of the Canvas' transform, see my answer to this similar question on rotation.
This is more of a thought than an answer, but what if you set a transform on the element that you did not want scaled that was the opposite of the canvas itself. So for example, if the canvas had a scale transform of 2.0, set the element to have a scale transform of 0.5. You could probably accomplish this by binding the transform values together using a value converter.
You'll probably want to make sure the element has a render transform origin of 0.5,0.5 so that it scales from the center.
The System.Drawing.Graphics class has a property CompositionMode with two options: SourceOver (which, based on the alpha component, blends whatever is drawn with the background already existing) or SourceCopy which simply overwrites the background with whatever is being drawn.
Does something similar exist in WPF?
In WPF when i draw a PolyLine for example on top of another the new PolyLine always alphablends with the background. I think that is independent of the container being used. I am using a Canvas but could not find a blend mode property anywhere. What I want to do is what the SourceCopy compositionmode mentioned above does. I.e. the new PolyLine should simply overwrite whatever is already on the Canvas.
Is there a simple way to do that, short of using pixel shaders (which - as far as I understand - wouldn't work anyways because I don't have access to the Canvas backbuffer).
I am not stuck with a Canvas and would be happy to use any container that supports overwrite mode.
I currently have a solution based on a WriteableBitmap for which I obtain a System.Drawing.Graphics context and then manipulate the CompositionMode. It works but since my window is fullscreen that solution has serious performance impacts.
Clarification and example:
The WPF window is fully transparent and so is the Canvas (back ground color(0,0,0,0)). Now I draw a PolyLine with a Color.FromArgb(128,128,0,0). I now have a semi-transparent red polyline. Next I draw the same PolyLine with Color.FromArgb(0,0,0,0). The result is the same as before because of the alpha blending taking place. What I want, however, is that the red polyline is erased with the second polyline (which is exactly what the SourceCopy mode in the Graphics class does.
I think all you need to do is make sure that the brushes used to fill/stroke the PolyLine have fully opaque alpha values (i.e. 255). Then the background shouldn't be blended into it.
You could apply a Clipping Mask, this way you can provide the path to clip over the elements that are below it, but it might be tough to maintain after a lot elements are required to be clipped...
I have a few 3d rectangles on my screen that I want to pivot around the Y axis.
I want to press down with the mouse, and rotate the 3d object to a max rotation, but when the user moves their mouse, I want to slightly rotate it so that it looks like a see-saw (rotating from a range of -13 to 13 degrees on the Y-Axis).
At the moment, I can do this, but my frame rate really really suffers when I move the mouse quickly. So for example, when I click the left side of the rectangle, I generate a storyboard and animation objects, then rotate the 3d object to -13 degrees. Then when I slightly move the mouse to the right, I want to rotate it to -12.5, and so on...
Again, I can do all of this, its just that the performance suffers greatly! It goes down to 5-FPS in some cases... which is not acceptable.
My question is am I doing this the best way? How else could you animate a rotation base on the users position on the screen?
Thanks for any help you can provide!
Mark
I assume you are doing the following:
Using a separate Model3D for the object you are rotating & including it in a Model3DGroup
Giving it a RotateTransform3D containing an AxisAngleRotation3D
Animating the AxisAngle3D's Axis property in the Storyboard
If my assumptions are correct I think we can conclude the problem is efficiency in rendering, since the CPU required to update a single Axis value, recompute the Transform, and update MILCore is negligible.
I can think of several ways that could improve the rendering performance:
If your Model3D being rotated is a GeometryModel3D backed by a MeshGeometry3D, do as much as you can to simplify the mesh and the materials used. It can also help to substitute a different mesh for closeups.
If the Model3D being rotated is a GeometryModel3D that uses VisualBrush brushes, during animation temporarily replace the VisualBrush with an ImageBrush containing a BitmapImage that is a snapshot of the Visual underlying the VisualBrush as of the instant the animation starts. When the animation ends, put backthe VisualBrush. The user probably won't notice that the contents of the object freeze temporarily when it rotates. (Note that this same technique can be used if your Visual3D is a Viewport2DVisual3D.)
If the Model3D being rotated is combined into a Model3DGroup with other objects but lies entirely in front of or behind the other groups, separate the model into its own separate Viewport3DVisual, appropriately layered to get the effect you want.
Simplify lighting or Material types
Monitor the actual frame rate and if it is going too low when using the storyboard, rotate the object immediately to where the mouse indicates without using an animation.
MSDN presents some tips on what impacts in WPF 3D performance. If you didn't stumble on it yet, check the items on "Performance Impact: High" list.
Edit: In march 2009, Josh Smith published an article on CodeProject that involves rotating 3D objetcs. Maybe you want to check his solution.
When I set the ViewportWidth of a Deepzoom image in Silverlight the zoom level changes very quickly. Is there a way I can set the time this zooming animation should take?
Thanks
The only way to do that would be to set UseSprings to false and animate the value of ViewportWidth yourself. This will also force you to animate the the ViewportOrigin as well when performing panning operations if you want to maintain the "spring" animation of panning.
You would need to test the performance of this. It could well be that MultiscaleImage may optimise its own animations differently than when these properties are being animated externally.
Try using the MultiScaleImage.UseSprings = true and the ZoomAboutLogicalPoint() method.
Although you cannot set the timing directly, each "Spring" takes exactly 1.5 seconds. So, if you wanted to, you could leave springs on, and then calculate the difference between the current viewportwidth, the viewport width you want to go to, and try and massage the timing this way. That being said, it may look awkward, so you'd have to test it first.
In processing a group of items, I wanted to display a unified image of the status of the group, so I essentially made a Grid of a number of progressbars with transparent backgrounds and various colored foregrounds all at the same cell.
I'm running into some transparency artifacts (purple bar is actually purple under the green, and sometimes it draws over the top, etc) and it just seems a bit wasteful. So, I decided to make my own, but now I've got a bit of paralysis on how to do it. Do I use the DrawingContext in FrameworkElement's OnRender, or is there something simpler? Is there a set of general rules when it comes to making your own control?
I pondered switching to a pie chart since those are easy to come by, but its high time I did something not off-the-shelf.
Thanks!
I'm not quite sure how you intend the progressbar to combine different progresses, but if say the furthest along progress is at the bottom of the z-index and the least along progress is at the top, then I'd do something on the lines of this:
1) I would probably create a user control for this new progresbar.
2) It would have a property called NumberOfProgresses, that is tied with an array containing status of said progresses.
3) Each progress would be represented by a Border item (or perhaps something more suitable up the visual tree), because it's a simple wpf control with a background property. The background property would be set to nice a looking progress style and the progress color can be bound in the style to say the border's borderbrush property. Making it easy to set the color of the progress.
4) The user control would have a method UpdateProgress which takes the percentage value and the index of the progress in the array as parameters.
5) As progresses are updated you can either, just calculate the appropriate width (user control actual width * percentage) for the border and play around with the Z index to get it displayed at the top/bottom, or stack the borders horizontaly, set the least along progress as first, then for the rest of the progresses you'd have to substract previous progresses lengths to get the same effect.
This way there would be no transparency induced artifacts and no OnRender()...
Mind you, in WPF there should be no reason to mess with OnRender this and OnRender that, like it was required in WinForms with OnPaint.
Just set up the elements via code to get the look you want, and let WPF do it's rendering ;)
I can imagine one problem with this user control though. You'd have to provide feedback to the user as to which color belongs to which progress. But that would probably take you back to square one, meaning it's better/simpler to just display multiple progressbars.