I am looking for ideas to create a WPF Brush with a brushed steel look, similar to the MacOSX Panther style, preferably without resorting to an ImageBrush.
Is there a funky way to use a GradientBrush to create this effect?
Thanks in advance!
I don't know how to do this easily with programmatic brushes, but when I have used Photoshop to create a brushed steel effect, I essentially created noise, then smeared (blurred) it in the direction of the brushing:
http://www.adamdorman.com/tutorials/brushed_steel_tutorial.php
As someone mentioned in comments, you may want to do this, and create some sort of (repeating?) image brush. If you want your brushed steel effect to be programmatically generated, you could write a mean filter to do the blur for you. Generating noise is simple enough :)
An example of implementing a mean filter:
http://homepages.inf.ed.ac.uk/rbf/HIPR2/mean.htm
Modify this to have a Nx1 matrix, or have small (zero) for weights not on the current line, and you will have a horizontal blur.
You could use a rotated LinearGradientBrush with many GradientStops in different grey tones. Well, it's at least an approach. For it to be scalable you would somehow need to make the GradientStops just one pixel wide which probably requires giving the size of the filled object to the brush, I guess. Might become a difficult task, but that's the fate of a real hacker, isn't it?
Related
I am writing a geoscience visualization application that uses wpf 3d. The user needs to be able to zoom deep into detail and out quick with minimum resources taken. I've decided to divide my slice (ModelVisual3D) into subrectangles (GeometryModel3D), so that each has it's own texture that changes when the camera zooms in (similar to Google maps).
The problem is that "cracks" are appearing between subrectangles, even though they actually have no empty space between them.
How to hide these? or is there any other way to assign multiple materials with different sizes to one ModelVisual3D?
PS I've tried making the background gray, light-gray, silver and white-smoke. It helps a little, but it's not acceptable. I've also tried overlapping the subrectangles, with no result.
Instead of your current setup you might want to make several textures at different resolutions and switch between these depending on the zoom level. (Mipmaps)
When getting really close you might replace the entire object and switch it for a much smaller one) and use a highly detailed texture.
It will require a bit more pre-processing but you will be able to use a single geometry.
Seems like changing ImageBrush's stretch to Stretch.None and using textures larger than the subsquare helps. Although now I need more precise control over texture coordinates for the surface.
I want to paint an WPF-Element like a colorwheel, you know from the HSV color space.
i dont know how to do this, i havnt found a possibility based on the standard brushes (SolidColorBrush, GradientBrush, etc)
How is a (mathematical) painting possible on wpf-shapes?
when you talk about Brushes and Pens you are talking about GDI+ and in GDI+ you have full control on anything since you are basically deciding which pixel to turn on, not so low of course but using lines, polygons and paths.
for a comparison between GDI+ and WPF or simply for some info regarding how to move from the first to the second, check this one: C# Transition between GDI+ and WPF there are some answers with lots of details
Where can I get started drawing animated geometry in C#? I would like to draw a sort of countdown timer by drawing a partially shaded circle. At start the circle would be fully shaded, at 75% 3/4 of the circle would be shaded and at 0 completely unshaded. I really don't know where to begin with something like this.
If you still don't understand what I need, a lot of games use this sort of animation to represent a "cooldown" on an item or skill. Like a second hand going around a clock, revealing what is beneath it.
WPF is my target application but I imagine I will need to use some sort of GDI api.
You could start out with the drawing examples here, for how to make your pie-like graphic:
http://www.codeproject.com/KB/WPF/PieChartDataBinding.aspx
It looks like they use StreamGeometryContext, along with LineTo and ArcTo.
You could then work on applying an animation to the properties on that graphic, so the "slice" gets bigger over time, by changing the arc length:
http://msdn.microsoft.com/en-us/library/ms752312.aspx#applyanimationstoproperty
You could then wrap this all up nicely in a UserControl, with custom dependency properties, so you can reuse this throughout your app.
Edit: I was thinking you meant the shaded pie like in World of Warcraft. What you want is actually simpler. See can poyrazoğlu's answer for the graphical approach to take (although you really only need the top black circle, if you're going with an opacity approach).
Yes, it's really easy with WPF.
Just create another circle on top of the circle, make that one black, and let a timer update the opacity of the top circle from 1 to 0 by time (or whatever you want).
This is the "easy" way. A more "convenient", or "WPF-style" approach would include Bindings and possibly value conversions, you'll be binding the opacity of the circle to a custom value with a value converter (or decrementing that value, anyway there are lots of ways).
Choose whatever you want. They'll both work.
I have an image that is a depth heatmap that I've filtered out anything further away than the first 25% of the image.
It looks something like this:
There are two blobs of color in the image, one is my hand (with part of my face behind it), and the other is the desk in the lower left corner. How can I search the image to find these blobs? I would like to be able to draw a rectangle around them if possible.
I can also do this (ignore shades, and filter to black or white):
Pick a random pixel as a seed pixel. This becomes area A. Repeatedly expand A until A doesn't get any bigger. That's your area.
The way to expand A is by looking for neighbor pixels to A, such that they have similar color to at least one neighboring pixel in A.
What "similar color" means to you is somewhat variable. If you can make exactly two colors, as you say in another answer, then "similar" is "equal". Otherwise, "similar" would mean colors that have RGB values or whatnot where each component of the two colors is within a small amount of each other (i.e. 255, 128, 128 is similar to 252, 125, 130).
You can also limit the selected pixels so they must be similar to the seed pixel, but that works better when a human is picking the seed. (I believe this is what is done in Photoshop, for example.)
This can be better than edge detection because you can deal with gradients without filtering them out of existence, and you don't need to process the resulting detected edges into a coherent area. It has the disadvantage that a gradient can go all the way from black to white and it'll register as the same area, but that may be what you want. Also, you have to be careful with the implementation or else it will be too slow.
It might be overkill for what you need, but there's a great wrapper for C# for the OpenCV libraries.
I have successfully used OpenCV in C++ for blob detection, so you might find it useful for what you're trying to do.
http://www.emgu.com/wiki/index.php/Main_Page
and the wiki page on OpenCV:
http://en.wikipedia.org/wiki/OpenCV
Edited to add: Here is a blobs detection library for Emgu in C#. There is even some nice features of ordering the blobs by descending area (useful for filtering out noise).
http://www.emgu.com/forum/viewtopic.php?f=3&t=205
Edit Again:
If Emgu is too heavyweight, Aforge.NET also includes some blob detection methods
http://www.aforgenet.com/framework/
If the image really is only two or more distinct colours (very little blur between colours), it is an easy case for an edge detection algorithm.
You can use something like the code sample from this question : find a color in an image in c#
It will help you find the x/y of specific colors in your image. Then you could use the min x/max x and the min y/max y to draw your rectangles.
Detect object from image based on object color by C#.
To detect a object based on its color, there is an easy algorithm for that. you have to choose a filtering method. Steps normally are:
Take the image
Apply ur filtering
Apply greyscalling
Subtract background and get your objects
Find position of all objects
Mark the objects
First you have to choose a filtering method, there are many filtering method provided for C#. Mainly I prefer AForge filters, for this purpose they have few filter:
ColorFiltering
ChannelFiltering
HSLFiltering
YCbCrFiltering
EuclideanColorFiltering
My favorite is EuclideanColorFiltering. It is easy and simple. For information about other filters you can visit link below. You have to download AForge dll for apply these in your code.
More information about the exact steps can be found here: Link
I have bitmaps of lines and text that have anti-alias applied to them. I want to develop a filter that removes tha anti-alias affect. I'm looking for ideas on how to go about doing that, so to start I need to understand how anti-alias algorithms work. Are there any good links, or even code out there?
I need to understand how anti-alias algorithms work
Anti-aliasing works by rendering the image at a higher resolution before it is down-sampled to the output resolution. In the down-sampling process the higher resolution pixels are averaged to create lower resolution pixels. This will create smoother color changes in the rendered image.
Consider this very simple example where a block outline is rendered on a white background.
It is then down-sampled to half the resolution in the process creating pixels having shades of gray:
Here is a more realistic demonstration of anti-aliasing used to render the letter S:
I am not familiar at all with C# programming, but I do have experience with graphics. The closest thing to an anti-anti-alias filter would be a sharpening filter (at least in practice, using Photoshop), usually applied multiple times, depending on the desired effect. The sharpening filter work best when there is great contrast already between the anti-aliased elements and the background, and even better if the background is one flat color, rather than a complex graphic.
If you have access to any advanced graphics editor, you could try a few tests, and if you're happy with the results you could start looking into sharpening filters.
Also, if you are working with grayscale bitmaps, an even better solution is to convert it to a B/W image - that will remove any anti-aliasing on it.
Hope this helps at least a bit :)