I would like to create animations where Duration is not set, but instead it is calculated based on an absolute speed setting. E.g. I want the animation to happen at 100 pixels/second and the duration is calculated automatically based on To and From values. If the path is 350 pixels, the animation will take 3.5 seconds to finish.
Duration.Automatic is NOT for this. Also Animation.SpeedRatio is a different thing.
I can of course calculate the duration from the path length, but I will have many objects moving on the screen, each created and removed procedural way and personally find it clumsy to bother with this.
What is a nice solution? Is there any built-in behaviour for this in Silverlight 4 or later?
Imaginary code:
DoubleAnimation ani = new DoubleAnimation();
ani.From = 0;
ani.To = 200;
ani.AbsoluteSpeed = "300 pixels / sec";
storyBoard1.Begin(); // now my animation will take 0.66 sec
Use code like:-
ani.Duration = new Duration(TimeSpan.FromSeconds(200 / myPixelsPerSecond))
This is not at all "clumsy".
If the use of such a fairly straight forward expression would merit the addition of new property what would happen if the same approach were applied to the rest of the available API? The set of these "helpful" properties would expand to unmanagable levels. The API would be crushed by the weight of zillions of similar properties all performing fairly simple expressions for setting the true fundemental properties.
Elegance (the opposite of clusmy) is having a small set of carefully chosen properties that can be combined in a zillions ways using simple expressions. Exactly as above.
Related
I'm using OxyPlot in my wpf application as line recorder. It's like the LiveDemo example.
On a larg visible data set, I get some UI performance issues and may the whole application could freez. It seems to be PlotModel.InvalidatePlot which is called with to many points to often, but I didn't found a better way.
In deep:
Using OxyPlot 2.0.0
I code all in the PlotModel. The Xaml PlotView is only binding to the PlotModel.
I cyclical collect data in a thread an put them in a DataSource (List of List which are ItemSoure for the LineSeries)
I have a class which calculates cyclical in a thread the presentation for x and y axis and a bit more. After all this stuff, it calls PlotModel.InvalidatePlot.
If I
have more than 100 k points on the display (no matter if in multiple LineSeries or not)
and add 1 DataPoint per LineSeries every 500 ms
and call PlotModel.InvalidatePlot every 200 ms
not only the PlotView has performance issues, also the window is very slow in reaction, even if I call PlotModel.InvalidatePlot (false).
My goal
My goal would be that the Windo / Application is working normally. It should not hang up because of a line recorder. The best would be if it has no performance issues, but I'm skeptical.
What I have found or tested
OxyPlot has Performance guidelines. I'm using ItemsSource with DataPoints. I have also tried adding them directly to the LineSeris.Points, but then the Plot doesn’t refresh anyway (even with an ObservableCollection), so I have to call PlotModel.InvalidatePlot, what results in the same effect. I cannot bind to a defined LineSeries in Xaml because I don’t know how much Lines will be there. Maybe I missed something on adding the points directly?
I have also found a Github issue 1286 which is describing a related problem, but this workaround is slower in my tests.
I have also checked the time which is elapsed on the call of PlotModel.InvalidatePlot, but the count of points does not affect it.
I have checked the UI thread and it seems it have trouble to handle this large set of points
If I zoom in to the plot and display under 20 k Points it looks so
Question:
Is there a way to handle this better, except to call PlotModel.InvalidatePlot much less?
Restrictions:
I also must Update Axis and Annotations. So, I think I will not come around to call PlotModel.InvalidatePlot.
I have found that using the OxyPlot Windows Forms implementation and then displaying it using Windows Form integration in WPF gives much better performance.
e.g.
var plotView = new OxyPlot.WindowsForms.PlotView();
plotView.Model = Plot;
var host = new System.Windows.Forms.Integration.WindowsFormsHost();
host.Child = plotView;
PlotContainer = host;
Where 'Plot' is the PlotModel you call InvalidatePlot() on.
And then in your XAML:
<ContentControl Content="{Binding PlotContainer}"/>
Or however else you want to use your WindowsFormsHost.
I have a similar problem and found that you can use a Decimator in LineSeries. It is documented in the examples: LineSeriesExamples.cs
The usage is like this:
public static PlotModel WithXDecimator()
{
var model = new PlotModel { Title = "LineSeries with X Decimator" };
var s1 = CreateSeriesSuitableForDecimation();
s1.Decimator = Decimator.Decimate;
model.Series.Add(s1);
return model;
}
This may solve the problem on my side, and I hope it helps others too. Unfortunately it is not documented in the documentation
For the moment I ended up with calculating the time for calling InvalidatePlot for the next time. I calculate it with the method given in this answer, wich returns the number of visible points. This rededuce the performance issue, but dosent fix the block on the UI Thread on calling InvalidatePlot.
I am using Appium's java-client 3.2.0 API; and would like to perform a "flick" gesture. I am guessing I need to use the swipe() method for this. My questions are
What value should I use as the duration so that the swipe is "fast" enough to be considered as a flick gesture?
Does the distance between start and end point matter?
if duration is fixed, longer distance means faster flick speed;
if distance is fixed, shorter duration means faster flick speed.
You can always set a breakpoint at the flicking point and change different values to see whether it's 'fast' enough.
I have trouble getting Map behave properly when calling ZoomToResolution and PanTo
I need to be able to Zoom into specific coordinate and center map.
The only way I got it working is by removing animations:
this.MapControl.ZoomDuration = new TimeSpan(0);
this.MapControl.PanDuration = new TimeSpan(0);
Otherwise if I make call like this:
control.MapControl.ZoomToResolution(ZoomLevel);
control.MapControl.PanTo(MapPoint());
It does one or another (i.e. pan or zoom, but not both). If (after animation) I call this code second time (map already zoomed or panned to needed position/level) - it does second part.
Tried this:
control.MapControl.ZoomToResolution(ZoomLevel, MapPoint());
Same issue, internally it calls above commands
So, my only workaround right now is to set Zoom/Pan duration to 0. And it makes for bad UX when using mouse.
I also tried something like this:
this.MapControl.ZoomDuration = new TimeSpan(0);
this.MapControl.PanDuration = new TimeSpan(0);
control.MapControl.ZoomToResolution(ZoomLevel);
control.MapControl.PanTo(MapPoint());
this.MapControl.ZoomDuration = new TimeSpan(750);
this.MapControl.PanDuration = new TimeSpan(750);
Which seems to be working, but then mouse interaction becomes "crazy". Mouse scroll will make map jump and zoom to random places.
Is there known solution?
The problem is the second operation replaces the previous one. You would have to wait for one to complete before starting the next one. But that probably doesn't give the effect you want.
Instead zoom to an extent, and you'll get the desired behavior. If you don't have the extent but only center and resolution, you can create one using the following:
var zoomToExtent = new Envelope(point.X - resolution * MapControl.ActualWidth/2, point.Y, point.X + resolution * MapControl.ActualWidth/2, point.Y);
Btw it's a little confusing in your code that you call your resolution "ZoomLevel". I assume this is a map resolution, and not a level number right? The esri map control doesn't deal with service-specific levels, but is agnostic to the data's levels and uses a more generic "units per pixels" resolution value.
I'm currently writing an eBook reader for Windows Phone Seven, and I'm trying to style it like the Kindle reader. In order to do so, I need to split my books up into pages, and this is going to get a lot more complex when variable font sizes are added.
To do this at the moment, I just add a word at a time into the textblock until it becomes higher than its container. As you can imagine though, with a document of over 120,000 words, this takes an unacceptable period of time.
Is there a way I can find out when the text would exceed the bounds (logically dividing it into pages), without having to actually render it? That way I'd be able to run it in a background thread so the user can keep reading in the meantime.
So far, the only idea that has occurred to me is to find out how the textblock decides its bounds (in the measure call?), but I have no idea how to find that code, because reflector didn't show anything.
Thanks in advance!
From what I can see the Kindle app appears to use a similar algorithm to the one you suggest. Note that:
it generally shows the % position through the book - it doesn't show total number of pages.
if you change the font size, then the first word on the page remains the same (so that's where the % comes from) - so the Kindle app just does one page worth of repagination assuming the first word of the page stays the same.
if you change the font size and then scroll back to the first page, then actually there is a discontinuity - they pull content forwards again in order to fill the first page.
Based on this, I would suggest you do not index the whole book. Instead just concentrate on the current page based on a "position" of some kind (e.g. character count - displayed as a percentage). If you have to do something on a background thread, then just look at the next page (and maybe the prev page) in order that scrolling can be more responsive.
Further to optimise your experience, there are a couple of changes you could make to your current algorithm that you could try:
try a different starting point and search increment for your algorithm - no need to start at one word and to then only add one word at a time.
assuming most of your books are ASCII, try caching the width of the common characters, and then work out the width of textblocks yourself.
Beyond that, I'd also quite like to try using <Run> blocks within your TextBlock - it may be possible to get the relative position of each Run within the TextBlock - although I've not managed to do this yet.
I do something similar to adjust font size for individual textboxes (to ensure they all fit). Basically, I create a TextBlock in code, set all my properties and check the ActualWidth and ActualHeight properties. Here is some pseudo code to help with your problem:
public static String PageText(TextBlock txtPage, String BookText)
{
TextBlock t = new TextBlock();
t.FontFamily = txtPage.FontFamily;
t.FontStyle = txtPage.FontStyle;
t.FontWeight = txtPage.FontWeight;
t.FontSize = txtPage.FontSize;
t.Text = BookText;
Size Actual = new Size();
Actual.Width = t.ActualWidth;
Actual.Height = t.ActualHeight;
if(Actual.Height <= txtPage.ActualHeight)
return BookText;
Double hRatio = txtPage.ActualHeight / Actual.Height;
return s.Substring((int)((s.Length - 1) * hRatio));
}
The above is untested code, but hopefully can get you started. Basically it sees if the text can fit in the box, if so you're good to go. If not, it finds out what percentage of the text can fit and returns it. This does not take word breaks into account, and may not be a perfect match, but should get you close.
You could alter this code to return the length rather than the actual substring and use that as your page size. Creating the textblock in code (with no display) actually performs pretty well (I do it in some table views with no noticeable lag). I wouldn't send all 120,000 words to this function, but a reasonable subset of some sort.
Once you have the ideal length you can use a RegEx to split the book into pages. There are examples on this site of RegEx that break on word boundaries after a specific length.
Another option, is to calculate page size ahead of time for each potential fontsize (and hardcode it with a switch statement). This could easily get crazy if you are allowing any font and any size combinations, and would be awful if you allowed mixed fonts/sizes, but would perform very well. Most likely you have a particular range of readable sizes, and just a few fonts. Creating a test app to calculate the text length of a page for each of these combinations wouldn't be that hard and would probably make your life easier - even if it doesn't "feel" right as a programmer :)
I didn't find any reference to this example from Microsoft called: "Principles of Pagination".
It has some interesting sample code running in Windows Phone.
http://msdn.microsoft.com/en-us/magazine/hh205757.aspx
You can also look this article about Page Transitions in Windows Phone and this other about the final touches in the E-Book project.
The code is downloadable: http://archive.msdn.microsoft.com/mag201111UIFrontiers/Release/ProjectReleases.aspx?ReleaseId=5776
You can query the FormattedText class that is used AFAIK inside textBlock. since this is the class being used to format text in preparation for Rendering, this is the most lower-level class available, and should be fast.
Is there some reason that identical math operations would take significantly longer in one Silverlight app than in another?
For example, I have some code that takes a list of points and transforms them (scales and translates them) and populates another list of points. It's important that I keep the original points intact, hence the second list.
Here's the relevant code (scale is a double and origin is a point):
public Point transformPoint(Point point) {
// scale, then translate the x
point.X = (point.X - origin.X) * scale;
// scale, then translate the y
point.Y = (point.Y - origin.Y) * scale;
// return the point
return point;
}
Here's how I'm doing the loop and timing, in case it's important:
DateTime startTime = DateTime.Now;
foreach (Point point in rawPoints) transformedPoints.Add(transformPoint(point));
Debug.Print("ASPX milliseconds: {0}", (DateTime.Now - startTime).Milliseconds);
On a run of 14356 points (don't ask, it's modeled off a real world number in the desktop app), the breakdown is as follows:
Silverlight app #1: 46 ms
Silverlight app #2: 859 ms
The first app is an otherwise empty app that is doing the loop in the MainPage constructor. The second is doing the loop in a method in another class, and the method is called during an event handler in the GUI thread, I think. But should any of that matter, considering that identical operations are happening within the loop itself?
There maybe something huge I'm missing in how threading works or something, but this discrepancy doesn't make sense to me at all.
In addition to the other comments and answers I'm going to read between the lines a little.
In the first app you have pretty much this code in isolation running in the MainPage constructor. IWO you've create a fresh Silverlight app and slapped this code in it and thats it.
In the second app you have more actual real world stuff. At the very least you have this code running as the result of a button click on a rudimentory UI. Therein lies the clue.
Take a blank app and drop a button on it. Run it and click the button, what does the button do? There are animations attached to visual states of the button. This animation (or other animations or loops) are likely running in parrallel with your code when you click the button. Timers (whether you do it properly with StopWatch or not) record elapsed time, not just the time your thread takes. Hence when other threads are doing other things (like animations) your timing will be off.
My first suspicion would be that Silverlight App #2 triggers a garbage collection. Scaling ~15,000 points should be taking a millisecond, not nearly a second.
Try to reduce memory allocations in your code. Can transformedPoints be an array, rather than a dynamically grown data structure?
You can also look at the GC performance counters, but simply reducing the memory allocation may turn out to be simpler.
Could it be possible your code is not being inlined in the CLR by the app that is running slower?
I'm not sure how the CLR in SL handles inlining, but here is a link to some of the prerequisites for inlining in 3.5 SP1.
http://udooz.net/blog/2009/04/clr-improvements-in-net-35-sp1/