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Dynamical rectangle plot c# wpf

I want to create a plot that dynamically displays active elements as rectangles. I have achieved a first version that is actually ok using OxyPlot.Annotations.RectangleAnnotation which I add to myPlotModel.Annotations, you can see it in the image hereafter:
Example of wanted display
The thing is that after a while, the amount of drawn rectangles make the update not smooth as I update the shown timewindow (which is set to 15 seconds). I have already set a maximum of drawn elements that suffice to cover the displayed window (i.e. the rectangles get removed as they are too far in the past), but the rendering is still jerky. I draw the rectangles by allocating them to an equal fraction of the Y-axis, that is the third one from the top gets:
rowNumber= 3.0
minimumY = maximalY - maximalY / totalElements * rowNumber
maximumY = maximalY - maximalY / totalElements * (rowNumber + 1.0)
And the Y-axis is hidden.
My question:
Is there a smarter way of creating such a display that would be less computationally heavy, and therefore allow a smoother update? I do not have to stick to OxyPlot, it is simply the easiest way that I found to obtain what I wanted.
Thanks for your answers!

Technically, the answer to your question is "Yes".
There are a number of ways to do this.
You could have a vertical itemscontrol that had an itemscontrol in it's template. That could have a canvas as it's itemspresenter and you could bind canvas.top and canvas.left to properties in it's content. Template each into a rectangle and bind height and width.
And of course do something about the scale on the bottom and the column of activity labels or whatever you want to call them there.
Unless you're using an absolutely ancient machine, that'd just fly.
It's quite a lot of work but it would probably be quicker to write that than to search through a load of alternative packages and decide which was optimal.

Draw a graph using arrays of pictureboxes

I am currently writing a program where I need to draw some graph's. I need to have a little bit specific layout in these graphs. For example I have three stages of a length in days defined by the user. a start stage of for example 30 days, a mid stage of 40 and an end stage of 20 days. These stages I want to have all a different backgroundcolor in the graph. I do that by drawing pictureboxes and adapting their widths to the stage lengths. Also for every day in the total length I want to draw a vertical line and for the amount of horizontal lines in the graph I take the maximum of y = f(x).
y = f(x) needs to be plotted on the graph. For I use many pictureboxes on the background I cannot use the graphics.DrawLine for it will be drawn behind the pictureboxes. So I decided to make the line with an array of pictureboxes ;) It works fine, but obviously it takes a lot of time to load the program now.
Is there another way to draw this graph using arrays of controls that require less effort from the computer? Or should I completely stop with the arrays?
(I wanted to post my picture here, but I don't have ten reputation yet because I'm a noobie :( )
Later on I will add more lines to this graph, but since I figured that my program is already slowing down I ceased programming those other lines and went to the all-knowing forum!
Any help will be much appreciated!
Greetz,
Arrie

The common form controls aren't really suitable for this purpose. I'd suggest taking a look at using libraries that give you more power and control over visuals and graphics.

#Kári is right:
If you want to stay with .NET only (no 3rd library dependence) you can use GDI. In .NET you can use by including System.Drawing.dll as an reference.
One simple yet correct approach would be:
create a target control (picturebox for example)
implement the OnPaintDraw Event which gives you an Graphics object
that contains many drawing methods. See MSDN for more information:
MSDN -> Graphics
The methods of Graphics will always draw above the control, so make sure your target control is visible an not behind any other control.
If GDI is not enough you can check out other libraries. (See .NET graph library around?)

More than 2 millions rectangles in a WPF canvas

I am creating a custom control for semiconductor wafermap
Each of those small rectangle need to satisfy following requirements;
1) Tooltip to show the index
2) clickable to include or exclude from the wafermap definition.
no of dies in the wafermap may cross 2 millions in the case of 1400 x 1450 dies.
at certain point i need to show all the dies in a window (most of the clicking will happen in zoomed view).
Currently I am adding each die separately using Rectangle shape and store the coordinate information (index like (10,10)) for the tooltip as an attached property.
I use different style to each die; depending on certain calculation and position of the die.
DieStyle1 = new Style { TargetType = typeof(Rectangle) };
DieStyle1.Setters.Add(new Setter(Shape.FillProperty, Brushes.MediumSlateBlue));
DieStyle1.Setters.Add(new Setter(Shape.StrokeProperty, Brushes.White));
DieStyle1.Setters.Add(new EventSetter(MouseDownEvent, new MouseButtonEventHandler(DieStyle1_MouseDown)));
this approach is slow and use high memory too. so suggest a better way to achieve this in WPF?

In creating a designer for christmas tree lights, I ran into the same problem. Using UIElement or Shapes is way too slow when you get to 100+ items. The best approach to handle a very large number of items entails using double-buffering with your own managed buffer of the image and a structure to handle the clicks. I have posted my project which should give you a good start. It can be obtained at:
http://sourceforge.net/projects/xlightsdesigner/
You are interested in the Controls\ChannelitemsCanvas.cs. It can be modified to suit your needs and uses a quad-tree to store the rectangles so that click events can be quickly determined.

equivalent CreateGraphics in wpf

So, I've used winForms .CreateGraphics to draw a variety of different things, from lines to boxes to images. It was very snappy and responsive.
I am trying to learn WPF in C#
I found that WPF allows me to "add" rectangle objects to a canvas which will display them properly. HOWEVER, I am drawing hundreds of thousands of rectangles at times, and the draw rate can become exceedingly slow, and the UI becomes less snappy when I move even 1 of the rectangles.
Painting directly onto an element in winForms was not very fast, but it was consistent regardless of how much I painted.
Is there a similar solution to doing this in WPF?
I tried adding a linq to System.Drawing, which gave me a Graphics object, but none of the wpf elements i tried have the .CreateGraphics() method.

WPF uses a different model for graphics manipulation than WinForms.
With WinForms, you are able to directly edit the pixels on the screen. The concept of your rectangle is lost after the pixels are drawn. Drawing pixels is a very fast operation.
With WPF, you are not controlling the pixels on the screen. DirectDraw is. DirectDraw is a vector-based compositing engine. You do not draw pixels. You define vector shapes (or visuals). The concept of a shape, or a rectangle, is RETAINED, even after the image is rendered to the screen. When you add a new rectangle which overlaps the others, ALL OTHER RECTANGLES NEED TO BE REDRAWN. This is likely where your performance is slowing down. This does not happen when using WinForms.
You can improve the performance of WPF a bit by overriding OnRender. You can cut out the overhead of the Rectangle object and directly provide the visuals. However, you are still not drawing pixels to the screen. You are defining shapes that DirectDraw uses to render the image. In this regard, the OnRender name may be a bit misleading.
I am sure you can find plenty of tricks to improve performance of your application in WPF. There are ways to still paint pixels - but that is kinda defeating the point of WPF.
What are you doing that requires thousands of rectangles?

You would need to create a control that overrides OnRender and do your drawing in there. There isn't a way for you to draw onto another control, but a control can draw itself.
Also, keep in mind that WPF uses retained graphics, so if you change something you need to invalidate the visual as needed.
EDIT:
Something like:
public class MyControl : Control {
public MyControl() {
this.Rects = new ObservableCollection<Rect>();
// TODO: attach to CollectionChanged to know when to invalidate visual
}
public ObservableCollection<Rect> Rects { get; private set; }
protected override void OnRender(DrawingContext dc) {
SolidColorBrush mySolidColorBrush = new SolidColorBrush();
mySolidColorBrush.Color = Colors.LimeGreen;
Pen myPen = new Pen(Brushes.Blue, 10);
foreach (Rect rect in this.Rects)
dc.DrawRectangle(mySolidColorBrush, myPen, rect);
}
}

As was said, WPF uses a retained graphics methodology so your actually creating 100,000 Rectangle objects in memory and then drawing all of them. The slowdowns are probably due to garbage collection and general memory issues.
Aside from override the OnRender method, here's a couple of things you could look into though.
Drawing the rectangles to an image in a background thread using the GDI methods your familiar and then write the result to a WPF WriteableBitmap
Use the D3DImage and take advantage of hardware acceleration. This requires you to know the DirectX (or Direct2D) libraries. If your interested in this approach, I'd suggest looking into SlimDx.

The problem is most likeley not that WPF can't render 1000s of graphic objects, but that your creating and adding items too far up the WPF object hierachy. It does after all use the GPU for all the graphical grunt work.
You should add objects as close to the "Visual" class as possible, as soon as you start adding objects based on the latter "UIElement" you are asking WPF to track user clicks, hovers and so on for each object, not just draw it.

Custom InkCanvas (MSDN Code Sample not working properly)

I want to use custom brushes with the InkCanvas.
Their is a code snippet from MSDN. (http://msdn.microsoft.com/en-us/library/ms747347.aspx)
If i use that code and move my mouse VERY fast i get space between the brushes(ellipses):
And my question is of course how to fix this but I'm also curious why this is happening (I want to learn from it) I thought maybe i did something wrong but even if i cut/paste the example it's happening.
One little thing i noticed when reading the code was this comment in the CustomStroke class
// Draw linear gradient ellipses between
// all the StylusPoints in the Stroke
Seems to me like it should draw ellipses between the points not only at the points.
I'm using C#.NET.
Again in short:
Why is this happening
Help me fix it :)

Why this is happening
The custom InkCanvas in the example draws an ellipse at every collected StrokePoint but makes no attempt to draw lines between them. The standard InkCanvas control is implemented by drawing lines between the points it is given. This is why the custom InkCanvas implementation from the example leaves gaps and the built-in one doesn't.
How to "fix" it
The custom code could easily be extended to not leave gaps: In addition to drawing ellipses at each point, it could draw lines between each pair of points.
Code to draw connecting lines might be added before the code to draw the ellipses, like this:
// Draw connecting lines
var geo = new StreamGeometry();
using(geoContext = geo.Open())
{
geoContext.StartFigure(stylusPoints[0], false, false);
geoContext.PolyLineTo(stylusPoints.Skip(1).Cast<Point>(), true, false);
}
drawingContext.DrawGeometry(null, connectingLinePen, geo);
// Draw ellipses
for(int i = 1; i < stylusPoints.Count; i++)
{
... etc ...
This code works by constructing a polyline StreamGeometry and then drawing it to the context. Using a StreamGeometry in this context is generally more efficient than creating a PathGeometry with a Polyline or doing a bunch of DrawLine calls directly on the drawingCanvas.
Note: Using a better digitizer won't solve the underlying problem, which is that the custom InkCanvas is actually designed to only show data at the sampled points and not in between.

ReDAeR
Look this
http://msdn.microsoft.com/en-us/library/bb531278.aspx

Why this is happening: The WPF InkCanvas control has a limited number of inputs per second when using a mouse; meaning that your stylus inputs will have greater and greater distances between them as you move the mouse faster and faster. The sample itself appears to draw elipses at every stylus input point, not in-between the points.
How to solve this: use a Tablet PC - a digitizer such as on a Tablet PC has a much higher number of inputs per second so it is more difficult to encounter, or fill in the blanks - essentially estimate based on previous points, perhaps a bezier curve.