I need a way to draw lines in WPF that have a rough, textured or distressed effect, as if they've been drawn by a real brush or pen stroke. I can go some way to doing what I want using graphic elements but this approach doesn't scale very well. Any suggestions?
I think that you can done it by processing pixels in bitmap
using a for-loop get pixels from brush-bitmap
and started another for-loop to set pixels on destinate bitmap
i've already done it once, but it's really a hard way
Related
It is possible to paint a pixel by using the FillRectangle method by setting the width and height to 1. However, it seems slow when painting 500*600 pixels in a loop by FillRectangle method. I searched for alternatives such as DrawLine method but this is slow also.
Can anyone offer me a solution?
Best Regards
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...
What i'm trying to do is making a "light projector" with visible ray(like with fog) also called volumetric light;
and which project a image (bitmap) ;
Because i would like to keep this project connected with a wpf application ( to get brush, position, rotation from data), i've choose to use WPF 3D
But it seem that WPF can't handle light projection or render ray.
So to do that, i have extruded each pixel of my source bitmap into a polygon colored by a solidColorBrush of the pixel color.
and keep the pixel order with (x,y) position.
For performance issue, i've set all the bitmaps to 32x32 px ( 1024 polygon for only one light !!)
But the result is too pixelated as you can see on the picture.
Moreover, it probably take much memory for nothing ...
my question is, how can i make it smooth or even rethink the extrusion system to optimize performance ...
Is any other tehnology that can be integrated into a wpf application and do that better or easier ?
Thanks, and sorry my English is pretty bad ...
alt text http://www.visualdmx.fr/pic_example.png
In Direct2D they recommend drawing similar things together, to avoid unnecessary GPU state changes. They also do some drawing operation reordering behind the scene just for that.
I have to draw a lot of rectangles which can have one of two colors. I'm thinking of doing the drawing in two passes, one for the rectangles with the first color and another for the ones with the other color.
Do you have any idea if this will improve the rendering speed? The speed I have right now is not that great. I draw into a DrawingContext obtained from a DrawingVisual.
I really don't know what effect grouping by brush will have, but there are some things you should check first:
Make sure all brushes, pens and other freezables are frozen.
Simplify your visual tree, try to reduce element count.
Try to reduce the number of elements that change every time you update your drawing.
Read: http://msdn.microsoft.com/en-us/magazine/dd483292.aspx
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.