Good evening residents =)
I'm drawing and then calling sleep in a cycle, but image control displays only the last instance of my painting and only when i exit the loop.
What should be done to fix it? A piece of code:
while (true)
{
...
if (TMax < T || TMin < T)
{
break;
}
UpdatePoints();
...
System.Threading.Thread.Sleep(500);
}
private void UpdatePoints()
{
DrawingVisual dv = new DrawingVisual();
using (DrawingContext dc = dv.RenderOpen())
{
...
dc.Close();
}
RenderTargetBitmap rtb = new RenderTargetBitmap(1000, 1000, 96, 96, PixelFormats.Pbgra32);
rtb.Render(dv);
critPoints.Source = rtb;
}
Create timer and use timer action to draw your picture, it doesn't work because your thread doesn't release when you use Sleep method, it is also interop your self and can't continue execution you program and repaint.
Related
I am trying to create sort of a radar. Radar is VisualCollection that consists of 360 DrawingVisual's (which represent radar beams). Radar is placed on Viewbox.
class Radar : FrameworkElement
{
private VisualCollection visuals;
private Beam[] beams = new Beam[BEAM_POSITIONS_AMOUNT]; // all geometry calculation goes here
public Radar()
{
visuals = new VisualCollection(this);
for (int beamIndex = 0; beamIndex < BEAM_POSITIONS_AMOUNT; beamIndex++)
{
DrawingVisual dv = new DrawingVisual();
visuals.Add(dv);
using (DrawingContext dc = dv.RenderOpen())
{
dc.DrawGeometry(Brushes.Black, null, beams[beamIndex].Geometry);
}
}
DrawingVisual line = new DrawingVisual();
visuals.Add(line);
// DISCRETES_AMOUNT is about 500
this.Width = DISCRETES_AMOUNT * 2;
this.Height = DISCRETES_AMOUNT * 2;
}
public void Draw(int beamIndex, Brush brush)
{
using (DrawingContext dc = ((DrawingVisual)visuals[beamIndex]).RenderOpen())
{
dc.DrawGeometry(brush, null, beams[beamIndex].Geometry);
}
}
protected override Visual GetVisualChild(int index)
{
return visuals[index];
}
protected override int VisualChildrenCount
{
get { return visuals.Count; }
}
}
Each DrawingVisual has precalculated geometry for DrawingContext.DrawGeometry(brush, pen, geometry). Pen is null and brush is a LinearGradientBrush with about 500 GradientStops. The brush gets updated every few milliseconds, lets say 16 ms for this example. And that is what gets laggy. Here goes the overall logic.
In MainWindow() constructor I create the radar and start a background thread:
private Radar radar;
public MainWindow()
{
InitializeComponent();
radar = new Radar();
viewbox.Child = radar;
Thread t = new Thread(new ThreadStart(Run));
t.Start();
}
In Run() method there is an infinite loop, where random brush is generated, Dispatcher.Invoke() is called and a delay for 16 ms is set:
private int beamIndex = 0;
private Random r = new Random();
private const int turnsPerMinute = 20;
private static long delay = 60 / turnsPerMinute * 1000 / (360 / 2);
private long deltaDelay = delay;
public void Run()
{
int beginTime = Environment.TickCount;
while (true)
{
GradientStopCollection gsc = new GradientStopCollection(DISCRETES_AMOUNT);
for (int i = 1; i < Settings.DISCRETES_AMOUNT + 1; i++)
{
byte color = (byte)r.Next(255);
gsc.Add(new GradientStop(Color.FromArgb(255, 0, color, 0), (double)i / (double)DISCRETES_AMOUNT));
}
LinearGradientBrush lgb = new LinearGradientBrush(gsc);
lgb.StartPoint = Beam.GradientStarts[beamIndex];
lgb.EndPoint = Beam.GradientStops[beamIndex];
lgb.Freeze();
viewbox.Dispatcher.Invoke(new Action( () =>
{
radar.Draw(beamIndex, lgb);
}));
beamIndex++;
if (beamIndex >= BEAM_POSITIONS_AMOUNT)
{
beamIndex = 0;
}
while (Environment.TickCount - beginTime < delay) { }
delay += deltaDelay;
}
}
Every Invoke() call it performs one simple thing: dc.DrawGeometry(), which redraws the beam under current beamIndex. However, sometimes it seems, like before UI updates, radar.Draw() is called few times and instead of drawing 1 beam per 16 ms, it draws 2-4 beams per 32-64 ms. And it is disturbing. I really want to achieve smooth movement. I need one beam to get drawn per exact period of time. Not this random stuff. This is the list of what I have tried so far (nothing helped):
placing radar in Canvas;
using Task, BackgroundWorker, Timer, custom Microtimer.dll and setting different Thread Priorities;
using different ways of implementing delay: Environment.TickCount, DateTime.Now.Ticks, Stopwatch.ElapsedMilliseconds;
changing LinearGradientBrush to predefined SolidColorBrush;
using BeginInvoke() instead of Invoke() and changing Dispatcher Priorities;
using InvalidateVisuals() and ugly DoEvents();
using BitmapCache, WriteableBitmap and RenderTargetBitmap (using DrawingContext.DrawImage(bitmap);
working with 360 Polygon objects instead of 360 DrawingVisuals. This way I could avoid using Invoke() method. Polygon.FillProperty of each polygon was bound to ObservableCollection, and INotifyPropertyChanged was implemented. So simple line of code {brushCollection[beamIndex] = (new created and frozen brush)} led to polygon FillProperty update and UI was getting redrawn. But still no smooth movement;
probably there were few more little workarounds I could forget about.
What I did not try:
use tools to draw 3D (Viewport) to draw 2D radar;
...
So, this is it. I am begging for help.
EDIT: These lags are not about PC resources - without delay radar can do about 5 full circles per second (moving pretty fast). Most likely it is something about multithread/UI/Dispatcher or something else that I am yet to understand.
EDIT2: Attaching an .exe file so you could see what is actually going on: https://dl.dropboxusercontent.com/u/8761356/Radar.exe
EDIT3: DispatcherTimer(DispatcherPriority.Render) did not help aswell.
For smooth WPF animations you should make use of the
CompositionTarget.Rendering event.
No need for a thread or messing with the dispatcher. The event will automatically be fired before each new frame, similar to HTML's requestAnimationFrame().
In the event update your WPF scene and you're done!
There is a complete example available on MSDN.
You can check some graphics bottleneck using the WPF Performance Suite:
http://msdn.microsoft.com/es-es/library/aa969767(v=vs.110).aspx
Perforator is the tool that will show you performance issues. Maybe you are using a low performance VGA card?
while (Environment.TickCount - beginTime < delay) { }
delay += deltaDelay;
The sequence above blocks the thread. Use instead "await Task.Delay(...)" which doesn't block the thread like its counterpart Thread.Sleep(...).
I'm a little baffled by a memory leak in my WPF code. I'm rendering some 3D geometry to several RenderTargetBitmaps, then rendering each of those to a large, master RenderTargetBitmap. But when I do this, I get a memory leak that crashes my app after just a minute or two.
I've reproduced the error in the following simplified piece of code.
private void timer1_Tick(object sender, EventArgs e) {
// if first time, create final stitch bitmap and set UI image source
if (stitch == null) {
stitch = new RenderTargetBitmap(1280, 480, 96, 96, PixelFormats.Pbgra32);
myImage.Source = stitch;
}
// create visual and render to img1
Rect rect = new Rect(new Point(160, 100), new Size(320, 80));
DrawingVisual dvis = new DrawingVisual();
using (DrawingContext dc = dvis.RenderOpen()) {
dc.DrawRectangle(System.Windows.Media.Brushes.LightBlue, (System.Windows.Media.Pen)null, rect);
}
RenderTargetBitmap img1 = new RenderTargetBitmap(640, 480, 96, 96, PixelFormats.Pbgra32);
img1.Render(dvis);
// create visual and render to final stitch
DrawingVisual vis = new DrawingVisual();
using (DrawingContext dc = vis.RenderOpen()) {
dc.DrawImage(img1, new Rect(0, 0, 640, 480));
}
stitch.Clear();
stitch.Render(vis);
}
Can anyone see anything obvious that is going wrong here? Why would this code have an egregious memory leak?
if you monitor behaviors of the RenderTargetBitmap class using Resource Monitor, you can see each time this class called, you lose 500KB of your memory. my Answer to your Question is: Dont use RenderTargetBitmap class so many times
You cant even release the Used Memory of RenderTargetBitmap.
If you really need using RenderTargetBitmap class, just add these lines at End of your code.
GC.Collect()
GC.WaitForPendingFinalizers()
GC.Collect()
This maybe solve your problem:
private void timer1_Tick(object sender, EventArgs e) {
// if first time, create final stitch bitmap and set UI image source
if (stitch == null) {
stitch = new RenderTargetBitmap(1280, 480, 96, 96, PixelFormats.Pbgra32);
myImage.Source = stitch;
}
// create visual and render to img1
Rect rect = new Rect(new Point(160, 100), new Size(320, 80));
DrawingVisual dvis = new DrawingVisual();
using (DrawingContext dc = dvis.RenderOpen()) {
dc.DrawRectangle(System.Windows.Media.Brushes.LightBlue, (System.Windows.Media.Pen)null, rect);
}
RenderTargetBitmap img1 = new RenderTargetBitmap(640, 480, 96, 96, PixelFormats.Pbgra32);
img1.Render(dvis);
// create visual and render to final stitch
DrawingVisual vis = new DrawingVisual();
using (DrawingContext dc = vis.RenderOpen()) {
dc.DrawImage(img1, new Rect(0, 0, 640, 480));
}
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
stitch.Clear();
stitch.Render(vis);
}
I was trying out different strategies for drawing a graph from the left edge of a control to the right edge. Until now we were using a Canvas with a polyline which performs OK, but could still use some improvement.
When I tried out DrawingContext.DrawLine I experienced incredibly bad performance, and I can't figure out why. This is the most condensed code I can come up with that demonstrates the problem:
public class TestControl : Control {
static Pen pen = new Pen(Brushes.Gray, 1.0);
static Random rnd = new Random();
protected override void OnRender(DrawingContext drawingContext) {
var previousPoint = new Point(0, 0);
for (int x = 4; x < this.ActualWidth; x += 4) {
var newPoint = new Point(x, rnd.Next((int)this.ActualHeight));
drawingContext.DrawLine(pen, previousPoint, newPoint);
previousPoint = newPoint;
}
}
}
And MainWindow.xaml just contains this:
<StackPanel>
<l:TestControl Height="16"/>
<!-- copy+paste the above line a few times -->
</StackPanel>
Now resize the window: depending on the number of TestControls in the StackPanel I experience a noticeable delay (10 controls) or a 30-second-total-standstill (100 controls) where I can't even hit the "Stop Debugger"-Button in VS...
I'm quite confused about this, obviously I am doing something wrong but since the code is so simple I don't see what that could be...
I am using .Net4 in case it matters.
You can gain performance by freezing the pen.
static TestControl()
{
pen.Freeze();
}
The most efficient way to draw a graph in WPF is to use DrawingVisual.
Charles Petzold wrote an excellent article explaining how to do it in MSDN Magazine:
Foundations: Writing More Efficient ItmesControls
The techniques work for displaying thousands of data points.
Ok, playing around with it a bit more, I found that freezing the pen had a huge impact. Now I create the pen in the constructor like this:
public TestControl() {
if (pen == null) {
pen = new Pen(Brushes.Gray, 1.0);
pen.Freeze();
}
}
The performance is now as I would expect it to be. I knew it had to be something simple...
Drawing in WPF becomes extremely slow if you use a pen with a dash style other than Solid (the default). This affects every draw method of DrawingContext that accepts a pen (DrawLine, DrawGeometry, etc.)
This question is really old but I found a way that improved the execution of my code which used DrawingContext.DrawLine aswell.
This was my code to draw a curve one hour ago:
DrawingVisual dv = new DrawingVisual();
DrawingContext dc = dv.RenderOpen();
foreach (SerieVM serieVm in _curve.Series) {
Pen seriePen = new Pen(serieVm.Stroke, 1.0);
Point lastDrawnPoint = new Point();
bool firstPoint = true;
foreach (CurveValuePointVM pointVm in serieVm.Points.Cast<CurveValuePointVM>()) {
if (pointVm.XValue < xMin || pointVm.XValue > xMax) continue;
double x = basePoint.X + (pointVm.XValue - xMin) * xSizePerValue;
double y = basePoint.Y - (pointVm.Value - yMin) * ySizePerValue;
Point coord = new Point(x, y);
if (firstPoint) {
firstPoint = false;
} else {
dc.DrawLine(seriePen, lastDrawnPoint, coord);
}
lastDrawnPoint = coord;
}
}
dc.Close();
Here is the code now:
DrawingVisual dv = new DrawingVisual();
DrawingContext dc = dv.RenderOpen();
foreach (SerieVM serieVm in _curve.Series) {
StreamGeometry g = new StreamGeometry();
StreamGeometryContext sgc = g.Open();
Pen seriePen = new Pen(serieVm.Stroke, 1.0);
bool firstPoint = true;
foreach (CurveValuePointVM pointVm in serieVm.Points.Cast<CurveValuePointVM>()) {
if (pointVm.XValue < xMin || pointVm.XValue > xMax) continue;
double x = basePoint.X + (pointVm.XValue - xMin) * xSizePerValue;
double y = basePoint.Y - (pointVm.Value - yMin) * ySizePerValue;
Point coord = new Point(x, y);
if (firstPoint) {
firstPoint = false;
sgc.BeginFigure(coord, false, false);
} else {
sgc.LineTo(coord, true, false);
}
}
sgc.Close();
dc.DrawGeometry(null, seriePen, g);
}
dc.Close();
The old code would take ~ 140 ms to plot two curves of 3000 points. The new one takes about 5 ms. Using StreamGeometry seems to be much more efficient than DrawingContext.Drawline.
Edit: I'm using the dotnet framework version 3.5
My guess is that the call to rnd.Next(...) is causing a lot of overhead each render. You can test it by providing a constant and then compare the speeds.
Do you really need to generate new coordinates each render?
I'm working on a personal project that creates an single image from a grid of images. It takes a while to generate the image and doesn't refresh everytime only once the code is done executing. How can the make the interface still functional (not locked up) when its generating the image.
So to start:
I have a N x N grid of identifiers, based on the identifier I draw a specific image at (x,y) with a given scaled height and width.
This image is regenerated each iteration and needs to be updated on the WPF. It is also bound to the ImageSource of the Image on the xaml side
My issue is 'How do I improve performance of generating this large image' and 'How do I refresh the image as many times as I need to (per generation).
for (int i = 0; i < numberOfIterations; i++)
{
// Do Some Work
UpdateImage();
}
...
BitmapImage imgFlower = new BitmapImage(new Uri(#"Images\Flower.bmp", UriKind.Relative));
BitmapImage imgPuppy = new BitmapImage(new Uri(#"Images\Puppy.bmp", UriKind.Relative));
ImageSource GeneratedImage{ get{ GenerateImage(); } set; }
...
void UpdateImage() { OnPropertyChanged("GeneratedImage"); }
...
ImageSource GenerateImage()
{
RenderTargetBitmap bmp = new RenderTargetBitmap(223, 223, 96, 96, PixelFormats.Pbgra32);
DrawingVisual drawingVisual = new DrawingVisual();
using (DrawingContext drawingContext = drawingVisual.RenderOpen())
{
double scaleRatio = CalculateScaleRatio();
DrawGridOfImages(drawingContext, scaleRatio);
}
bmp.Render(drawingVisual);
return bmp;
}
...
DrawGridOfImages(...)
{
double x,y;
for (int r = 0; r < NumberOfRows; r++)
{
x = r * scaleRatio;
for (int c = 0; c < NumberOfColumns; c++)
{
y = c * scaleRatio;
switch (imageOccupancy[r, c])
{
case Flower: drawingContext.DrawImage(imgFlower, new Rect(x,y,scaleRatio,scaleRation));
case Puppy: drawingContext.DrawImage(imgPuppy, new Rect(x,y,scaleRatio,scaleRatio));
}
}
}
}
There are two ways. To first and most beneficial would be to improve the perceived performance, do this by generating the image on a worker thread and use events to update the image on the UI thread at key points so your users can see the progress.
To improve actual performance, if you are targeting and using multicore systems you can try parallel functions if your iterations can actually be performed in parallel. This will require some work and a different mindset but will help if you put the effort in. I'd recommend studying PLINQ to get started.
I am try to add a flip animation to a user control I built. The user control is simple it has a 87x87 image front and back and some properties. It is suppose to represent a tile in a game I am working on for fun. I am trying to animate a flipping affect of the user picking the tile from the deck. I feel I need to do this through code instead of xaml for two reasons: 1. There is another transform after the tile is flip to rotate the tile (currently working) 2. After the tile is flipped I want to unhook the event.
The issue that I am getting is only the last animation runs after the method has exited.
I think I need a Storyboard but all the examples I looked at confused me in two ways:
How do I change the image mid story board, and what do I set the targetProperty to be
I have been working off these two blogs.
http://www.codeguru.com/csharp/csharp/cs_misc/userinterface/article.php/c12221
http://blogs.msdn.com/tess/archive/2009/03/16/silverlight-wpf-flipimage-animation.aspx
public void FlipFront()
{
DoubleAnimation flipfront = new DoubleAnimation(0, 90, new Duration(new TimeSpan(0, 0, 1)));
SkewTransform skew = new SkewTransform();
this.RenderTransform = skew;
skew.BeginAnimation(SkewTransform.AngleYProperty, flipfront);
}
public void FlipBack()
{
ImageSourceConverter source = new ImageSourceConverter();
this.ImageFace.Source = new BitmapImage(new Uri("Back.jpg", UriKind.Relative));
DoubleAnimation flipfront = new DoubleAnimation(90, 0, new Duration(new TimeSpan(0, 0, 1)));
SkewTransform skew = new SkewTransform();
this.RenderTransform = skew;
skew.BeginAnimation(SkewTransform.AngleYProperty, flipfront);
}
public void Flip()
{
FlipFront();
FlipBack();
}
I broke flip into two separate methods because I though it would help fix the issue I am experiencing.
Wow, this hasn't been updated in a loong time...just in case anybody's tracking this one:
The problem is you're not waiting for the "flip front" animation to complete before immediately starting the "flip back" - now since you're basically force-jumping the Y angle animation immediately to 90 degrees, that's why it looks like it's not firing properly.
There are a LOT of ways you can work around this - the first thing that jumps to mind is that the DoubleAnimations have a method on them called CreateClock, which will return you back an AnimationClock object. That object has a Completed event on it, which will tell you when that animation is "done". Attach a handler (remember you'll want to detach it lest you leak memory), and call your "start flipping to back" method there. I've thrown something very inefficient together, but it'll show the principle:
public AnimationClock StartFlipFrontAnimation()
{
this.ImageFace.Source = _frontFace;
DoubleAnimation flipfront = new DoubleAnimation(0, 90, new Duration(new TimeSpan(0, 0, 3)));
SkewTransform skew = new SkewTransform();
this.RenderTransform = skew;
skew.BeginAnimation(SkewTransform.AngleYProperty, flipfront);
return flipfront.CreateClock();
}
public AnimationClock StartFlipBackAnimation()
{
this.ImageFace.Source = _backFace;
DoubleAnimation flipfront = new DoubleAnimation(90, 0, new Duration(new TimeSpan(0, 0, 3)));
SkewTransform skew = new SkewTransform();
this.RenderTransform = skew;
skew.BeginAnimation(SkewTransform.AngleYProperty, flipfront);
return flipfront.CreateClock();
}
public void BeginFlip()
{
var frontClk = StartFlipFrontAnimation();
frontClk.Completed += FrontFlipDone;
}
private void FrontFlipDone(object sender, EventArgs args)
{
var clk = sender as AnimationClock;
if(clk != null)
{
clk.Completed -= FrontFlipDone;
}
var backClk = StartFlipBackAnimation();
}