I just did a simple application to get a screenshot periodically.
The main issue I have got is that application freezes when I move it.
So the main goal is to take out this influence of the screenshot, threads and etc.
I put here all code and it works so u can reproduce it.
Here is some .NET Profiling info of this code.
Any clue how do I can fix it?
XAML
<Window x:Class="Screenshot.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded" >
<Grid Height="Auto">
<Image Name="Image1"/>
</Grid>
</Window>
C#
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
ScreenGrabber grabber;
private void Window_Loaded(object sender, RoutedEventArgs e)
{
grabber = new ScreenGrabber(5);
grabber.Changed += new ChangedEventHandler(grabber_Changed);
}
void grabber_Changed(object sender, EventArgs e)
{
Image1.Dispatcher.Invoke(new Action(() => {
BitmapSource bs = ((ScreenGrabber)sender).GetImage();
Image1.Width = bs.Width;
Image1.Height = bs.Height;
Image1.Source = bs;
} ));
}
}
C# DLL
namespace MyScreenGrabber
{
public delegate void ChangedEventHandler(object sender, EventArgs e);
public class ScreenGrabber : Window
{
public event ChangedEventHandler Changed;
protected virtual void OnChanged(EventArgs e)
{
if (Changed != null)
Changed(this, e);
}
byte[] BitmapData { set; get; }
int Interval { set; get; }
DispatcherTimer Timer { set; get; }
public ScreenGrabber(int interval)
{
Interval = interval;
Timer = new DispatcherTimer();
Timer.Interval = new TimeSpan(0, 0, Interval);
Timer.Tick += new EventHandler(Timer_Tick);
Timer.Start();
}
void Timer_Tick(object sender, EventArgs e)
{
WindowInteropHelper windowInteropHelper = windowInteropHelper = new WindowInteropHelper(this);
Screen screen = Screen.FromHandle(windowInteropHelper.Handle);
using (MemoryStream ms = new MemoryStream())
{
if (screen != null)
{
using (Bitmap bitmap = new Bitmap(screen.Bounds.Size.Width, screen.Bounds.Size.Height))
{
using (Graphics g = Graphics.FromImage(bitmap))
{
g.CopyFromScreen(screen.Bounds.X, screen.Bounds.Y, 0, 0, screen.Bounds.Size, CopyPixelOperation.SourceCopy);
}
ImageCodecInfo myImageCodecInfo;
myImageCodecInfo = GetEncoderInfo("image/jpeg");
System.Drawing.Imaging.Encoder myEncoder;
myEncoder = System.Drawing.Imaging.Encoder.Quality;
EncoderParameters encoderParameters = new EncoderParameters();
EncoderParameter encoderParameter = new EncoderParameter(myEncoder, 25L);
encoderParameters.Param[0] = encoderParameter;
bitmap.Save(ms, myImageCodecInfo, encoderParameters);
BitmapData = ms.ToArray();
OnChanged(EventArgs.Empty);
}
}
}
}
static ImageCodecInfo GetEncoderInfo(String mimeType)
{
int j;
ImageCodecInfo[] encoders;
encoders = ImageCodecInfo.GetImageEncoders();
for (j = 0; j < encoders.Length; ++j)
{
if (encoders[j].MimeType == mimeType)
return encoders[j];
}
return null;
}
public BitmapSource GetImage()
{
using (MemoryStream ms = new MemoryStream(this.BitmapData))
{
var decoder = BitmapDecoder.Create(ms, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
return decoder.Frames[0];
}
}
}
}
Optimized code:
namespace MyScreenGrabber
{
public delegate void ChangedEventHandler(object sender, EventArgs e);
public class ScreenGrabber : Window
{
public event ChangedEventHandler Changed;
protected virtual void OnChanged(EventArgs e)
{
if (Changed != null)
Changed(this, e);
}
byte[] BitmapData { set; get; }
int Interval { set; get; }
WindowInteropHelper windowInteropHelper;
Screen screen;
DispatcherTimer Timer { set; get; }
BackgroundWorker worker = new BackgroundWorker();
public ScreenGrabber(int interval)
{
Interval = interval;
windowInteropHelper = windowInteropHelper = new WindowInteropHelper(this);
screen = Screen.FromHandle(windowInteropHelper.Handle);
isDone = true;
Timer = new DispatcherTimer();
Timer.Interval = new TimeSpan(0, 0, Interval);
Timer.Tick += new EventHandler(Timer_Tick);
Timer.Start();
worker.DoWork += new DoWorkEventHandler(worker_DoWork);
worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
}
void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
OnChanged(EventArgs.Empty);
isDone = true;
}
bool isDone;
void worker_DoWork(object sender, DoWorkEventArgs e)
{
GetScreenshot();
}
void Timer_Tick(object sender, EventArgs e)
{
if (isDone)
{
isDone = false;
worker.RunWorkerAsync();
}
}
void GetScreenshot()
{
using (MemoryStream ms = new MemoryStream())
{
if (screen != null)
{
using (Bitmap bitmap = new Bitmap(screen.Bounds.Size.Width, screen.Bounds.Size.Height))
{
using (Graphics g = Graphics.FromImage(bitmap))
{
g.CopyFromScreen(screen.Bounds.X, screen.Bounds.Y, 0, 0, screen.Bounds.Size, CopyPixelOperation.SourceCopy);
}
ImageCodecInfo myImageCodecInfo;
myImageCodecInfo = GetEncoderInfo("image/jpeg");
System.Drawing.Imaging.Encoder myEncoder;
myEncoder = System.Drawing.Imaging.Encoder.Quality;
EncoderParameters encoderParameters = new EncoderParameters();
EncoderParameter encoderParameter = new EncoderParameter(myEncoder, 25L);
encoderParameters.Param[0] = encoderParameter;
bitmap.Save(ms, myImageCodecInfo, encoderParameters);
BitmapData = ms.ToArray();
}
}
}
}
static ImageCodecInfo GetEncoderInfo(String mimeType)
{
int j;
ImageCodecInfo[] encoders;
encoders = ImageCodecInfo.GetImageEncoders();
for (j = 0; j < encoders.Length; ++j)
{
if (encoders[j].MimeType == mimeType)
return encoders[j];
}
return null;
}
public BitmapSource GetImage()
{
using (MemoryStream ms = new MemoryStream(this.BitmapData))
{
var decoder = BitmapDecoder.Create(ms, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
return decoder.Frames[0];
}
}
}
}
I believe you can avoid this by using a background worker process to execute the function that takes the screenshot.
As the background worker uses another thread and the main thread continues to render the UI , it should not get stuck.
EDIT :// I found this question on SO that might clarify things on Background Workers VS Delegates
Good luck!