Develop Reference

.NET 4.0 Graphics library - How can I capture the "whole" screen?

I'm coding a small app to take a screenshot every X seconds and I've ran into a small but annoying roadblock. Take this image, for example:
Screen captured using the default 'Print Screen' function on Windows 7
If I try to take the same screenshot by using the default .NET 4 Graphics library, the circled area doesn't show up. Same happens with Visual Studio tabbed menus and some other apps I can't remember. The rest of the image comes out fine, tho.
This is the code I'm using. I might be screwing something up but I can't figure it for the life of me. Any help would be appreciated:
memoryImage = new Bitmap(resolution.Width, resolution.Height);
Size s = new Size(memoryImage.Width, memoryImage.Height);
// Create graphics
Console.WriteLine("Creating Graphics...");
Console.WriteLine();
Graphics memoryGraphics = Graphics.FromImage(memoryImage);
// Copy data from screen
Console.WriteLine("Copying data from screen...");
Console.WriteLine();
memoryGraphics.CopyFromScreen(0, 0, 0, 0, s);

This test saves correctly the whole screen on my configuration (Windows 10, VS 2015) =>
Rectangle screenBounds = Screen.GetBounds(System.Drawing.Point.Empty);
using (Bitmap bitmap = new Bitmap(screenBounds.Width, screenBounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb))
{
using (Graphics g = Graphics.FromImage(bitmap))
{
g.CopyFromScreen(0, 0, 0, 0, bitmap.Size, CopyPixelOperation.SourceCopy);
}
bitmap.Save("e:\\ScreenCopy.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
}

Grayscale 8BPP bitmap for SharpDX.Direct2D1.Bitmap

I am currently making a 2D application using SharpDX.Direct2D1.
Here is my setup for my 2D deviceContext that works correctly.
m_swapchaindesc = New SwapChainDescription()
With m_swapchaindesc
.BufferCount = 2
.ModeDescription =
New ModeDescription(control.Width, control.Height,
New Rational(60, 1), Format.R8G8B8A8_UNorm)
.IsWindowed = True
.OutputHandle = control.Handle
.SampleDescription = New SampleDescription(1, 0)
.SwapEffect = SwapEffect.Discard
.Usage = Usage.RenderTargetOutput
End With
SharpDX.Direct3D11.Device.CreateWithSwapChain(DriverType.Hardware, DeviceCreationFlags.BgraSupport Or DeviceCreationFlags.Debug, m_swapchaindesc, m_device, m_swapChain)
Dim dxgiDevice As SharpDX.DXGI.Device = m_device.QueryInterface(Of SharpDX.DXGI.Device)()
m_2dDevice = New SharpDX.Direct2D1.Device(dxgiDevice)
m_d2dContext = New SharpDX.Direct2D1.DeviceContext(m_2dDevice, SharpDX.Direct2D1.DeviceContextOptions.None)
m_properties = New BitmapProperties(New SharpDX.Direct2D1.PixelFormat(SharpDX.DXGI.Format.R8G8B8A8_UNorm, SharpDX.Direct2D1.AlphaMode.Premultiplied), 96, 96)
m_backBuffer = m_swapChain.GetBackBuffer(Of Surface)(0)
m_2dTarget = New SharpDX.Direct2D1.Bitmap(m_d2dContext, m_backBuffer, m_properties)
m_d2dContext.Target = m_2dTarget
My question : I want to draw 8bpp bitmap on a grayscale to my deviceContext, which means I don't need it to be 32bits per pixel which takes a loooot of memory. I would like for it to be only 8 bits for memory purpose. The problem when I do so, which means setting up my BitmapProperties, there is only a Format.R8_Unorm Or Format.A8_Unorm that seems interesting since I guess they only have 8bpp. However, when I put this format and I am trying to instantiate my SharpDX.Direct2D1.Bitmap, it returns an error message that says WRONGPIXELFORMAT.
I realised that only Format.R8G8B8A8_Unorm seems to work when creating bitmap, which I don't need.
Have any of you worked with 8bpp grayscale bitmap on SharpDX ?

You cannot use 8BPP bitmaps with SharpDX (DirectX). This is not a supported format by DirectX. To be able to display a grayscale image, You have to set all values of yours rgb to the same one, or apply a shaders to your image that converts all colors to gray.

Taking a screenshot using Graphics.CopyFromScreen with 150% scaling

I'm trying to create a screenshot/bitmap of my screen. I wrote this function:
public static Bitmap CreateScreenshot(Rectangle bounds)
{
var bmpScreenshot = new Bitmap(bounds.Width, bounds.Height,
PixelFormat.Format32bppArgb);
var gfxScreenshot = Graphics.FromImage(bmpScreenshot);
gfxScreenshot.CopyFromScreen(bounds.X, bounds.Y,
0, 0,
new Size(bounds.Size.Width, bounds.Size.Height),
CopyPixelOperation.SourceCopy);
return bmpScreenshot;
}
This function is being called in my overlay form that should draw the bitmap onto itself. I'm currently using GDI+ for the whole process.
private void ScreenshotOverlay_Load(object sender, EventArgs e)
{
foreach (Screen screen in Screen.AllScreens)
Size += screen.Bounds.Size;
Location = Screen.PrimaryScreen.Bounds.Location;
_screenshot = BitmapHelper.CreateScreenshot(new Rectangle(new Point(0, 0), Size));
Invalidate(); // The screenshot/bitmap is drawn here
}
Yep, I dispose the bitmap later, so don't worry. ;)
On my laptop and desktop computer this works fine. I've tested this with different resolutions and the calculations are correct. I can see an image of the screen on the form.
The problem starts with the Surface 3. All elements are being scaled by a factor of 1.5 (150%). This consequently means that the DPI changes. If I try to take a screenshot there, it does only capture like the upper-left part of the screen but not the whole one.
I've made my way through Google and StackOverflow and tried out different things:
Get the DPI, divide it by 96 and multiply the size components (X and Y) of the screen with this factor.
Add an entry to application.manifest to make the application DPI-aware.
The first way did not bring the desired result. The second one did, but the whole application would have to be adjusted then and this is quite complicated in Windows Forms.
Now my question would be: Is there any way to capture a screenshot of the whole screen, even if it is has a scalation factor higher than 1 (higher DPI)?
There must be a way to do this in order to make it working everywhere.
But at this point I had no real search results that could help me.
Thanks in advance.

Try this, which is found within SharpAVI's library. It works well on devices regardless of resolution scale. And I have tested it on Surface 3 at 150%.
System.Windows.Media.Matrix toDevice;
using (var source = new HwndSource(new HwndSourceParameters()))
{
toDevice = source.CompositionTarget.TransformToDevice;
}
screenWidth = (int)Math.Round(SystemParameters.PrimaryScreenWidth * toDevice.M11);
screenHeight = (int)Math.Round(SystemParameters.PrimaryScreenHeight * toDevice.M22);
SharpAVI can be found here: https://github.com/baSSiLL/SharpAvi It is for videos but uses a similar copyFromScreen method when getting each frame:
graphics.CopyFromScreen(0, 0, 0, 0, new System.Drawing.Size(screenWidth, screenHeight));

Before taking your screen shot, you can make the process DPI aware:
[System.Runtime.InteropServices.DllImport("user32.dll")]
public static extern bool SetProcessDPIAware();
private static Bitmap Screenshot()
{
SetProcessDPIAware();
var screen = System.Windows.Forms.Screen.PrimaryScreen;
var rect = screen.Bounds;
var size = rect.Size;
Bitmap bmpScreenshot = new Bitmap(size.Width, size.Height);
Graphics g = Graphics.FromImage(bmpScreenshot);
g.CopyFromScreen(0, 0, 0, 0, size);
return bmpScreenshot;
}

Emgucv Convert<Hsv, Byte>() image

I am having a problem with EmguCV. I used a demo application, and edited it to my needs.
It involves the following function:
public override Image<Gray, byte> DetectSkin(Image<Bgr, byte> Img, IColor min, IColor max)
{
Image<Hsv, Byte> currentHsvFrame = Img.Convert<Hsv, Byte>();
Image<Gray, byte> skin = new Image<Gray, byte>(Img.Width, Img.Height);
skin = currentHsvFrame.InRange((Hsv)min,(Hsv)max);
return skin;
}
In the demo application, the Image comes from a video. The frame is capured from the video like this:
Image<Bgr, Byte> currentFrame;
grabber = new Emgu.CV.Capture(#".\..\..\..\M2U00253.MPG");
grabber.QueryFrame();
currentFrame = grabber.QueryFrame();
In my application, the Image comes from a microsoft kinect stream.
I use the following function:
private void SensorColorFrameReady(object sender, ColorImageFrameReadyEventArgs e)
{
using (ColorImageFrame colorFrame = e.OpenColorImageFrame())
{
if (colorFrame != null)
{
// Copy the pixel data from the image to a temporary array
colorFrame.CopyPixelDataTo(this.colorPixels);
// Write the pixel data into our bitmap
this.colorBitmap.WritePixels(
new Int32Rect(0, 0, this.colorBitmap.PixelWidth, this.colorBitmap.PixelHeight),
this.colorPixels,
this.colorBitmap.PixelWidth * sizeof(int),
0);
Bitmap b = BitmapFromWriteableBitmap(this.colorBitmap);
currentFrame = new Image<Bgr, byte>(b);
currentFrameCopy = currentFrame.Copy();
skinDetector = new YCrCbSkinDetector();
Image<Gray, Byte> skin = skinDetector.DetectSkin(currentFrame, YCrCb_min, YCrCb_max);
}
}
}
private static System.Drawing.Bitmap BitmapFromWriteableBitmap(WriteableBitmap writeBmp)
{
System.Drawing.Bitmap bmp;
using (System.IO.MemoryStream outStream = new System.IO.MemoryStream())
{
BitmapEncoder enc = new BmpBitmapEncoder();
enc.Frames.Add(BitmapFrame.Create((BitmapSource)writeBmp));
enc.Save(outStream);
bmp = new System.Drawing.Bitmap(outStream);
}
return bmp;
}
Now, the demo application works, and mine doesn't. Mine gives the following exception:
And, the image here, contains the following:
I really don't understand this exception. And, now, when I run the demo, working aplication, the image, contains:
Which is, in my eyes, exactly the same. I really don't understand this. Help is very welcome!

To make things easier I've uploaded a working WPF solution for you to the code reference sourceforge page I've been building:
http://sourceforge.net/projects/emguexample/files/Capture/Kinect_SkinDetector_WPF.zip/download
https://sourceforge.net/projects/emguexample/files/Capture/
This was designed and tested using EMGU x64 2.42 so in the Lib folder of the project you will find the referenced dlls. If you are using a different version you will need to delete the current references and replace them with the version you're using.
Secondly the project is design like all projects from the code reference library to be built from the Emgu.CV.Example folder into the ..\EMGU 2.X.X.X\bin.. global bin directory where the opencv compiled libraries are within a folder either x86 or x64.
If you struggle to get the code working I can provide all components but I hate redistributing all the opencv files that you already have so let me know if you want this.
You will need to resize the Mainwindow manually to display both images as I didn't spend to much time playing with layout.
So the code...
In the form initialisation method I check for the kinect sensor and set up the eventhandlers for the frames ready. I have left the original threshold values and skinDetector type although I don't use the EMGU version I just forgot to remove it. You will need to play with the threshold values and so on.
//// Look through all sensors and start the first connected one.
//// This requires that a Kinect is connected at the time of app startup.
//// To make your app robust against plug/unplug,
//// it is recommended to use KinectSensorChooser provided in Microsoft.Kinect.Toolkit (See components in Toolkit Browser).
foreach (var potentialSensor in KinectSensor.KinectSensors)
{
if (potentialSensor.Status == KinectStatus.Connected)
{
this.KS = potentialSensor;
break;
}
}
//If we have a Kinect Sensor we will set it up
if (null != KS)
{
// Turn on the color stream to receive color frames
KS.ColorStream.Enable(ColorImageFormat.RgbResolution640x480Fps30);
//Turn on the depth stream to recieve depth frames
KS.DepthStream.Enable(DepthImageFormat.Resolution640x480Fps30);
//Start the Streaming process
KS.Start();
//Create a link to a callback to deal with the frames
KS.AllFramesReady += new EventHandler<AllFramesReadyEventArgs>(KS_AllFramesReady);
//We set up a thread to process the image/disparty map from the kinect
//Why? The kinect AllFramesReady has a timeout if it has not finished the streams will simply stop
KinectBuffer = new Thread(ProcessBuffer);
hsv_min = new Hsv(0, 45, 0);
hsv_max = new Hsv(20, 255, 255);
YCrCb_min = new Ycc(0, 131, 80);
YCrCb_max = new Ycc(255, 185, 135);
detector = new AdaptiveSkinDetector(1, AdaptiveSkinDetector.MorphingMethod.NONE);
skinDetector = new YCrCbSkinDetector();
}
I always play with the kinect data in a new thread for speed but you may want to advanced this to a Background worker if you plan to do any more heavy processing so it is better managed.
The thread calls the ProcessBuffer() method you can ignore all the commented code as this is the remanence of the code used to display the depth image. Again I'm using the Marshall copy method to keep things fast but the thing to look for is the Dispatcher.BeginInvoke in WPF that allows the images to be displayed from the Kinect thread. This is required as I'm not processing on the main thread.
//This takes the byte[] array from the kinect and makes a bitmap from the colour data for us
byte[] pixeldata = new byte[CF.PixelDataLength];
CF.CopyPixelDataTo(pixeldata);
System.Drawing.Bitmap bmap = new System.Drawing.Bitmap(CF.Width, CF.Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb);
BitmapData bmapdata = bmap.LockBits(new System.Drawing.Rectangle(0, 0, CF.Width, CF.Height), ImageLockMode.WriteOnly, bmap.PixelFormat);
IntPtr ptr = bmapdata.Scan0;
Marshal.Copy(pixeldata, 0, ptr, CF.PixelDataLength);
bmap.UnlockBits(bmapdata);
//display our colour frame
currentFrame = new Image<Bgr, Byte>(bmap);
Image<Gray, Byte> skin2 = skinDetector.DetectSkin(currentFrame, YCrCb_min, YCrCb_max);
ExtractContourAndHull(skin2);
DrawAndComputeFingersNum();
//Display our images using WPF Dispatcher Invoke as this is a sub thread.
Dispatcher.BeginInvoke((Action)(() =>
{
ColorImage.Source = BitmapSourceConvert.ToBitmapSource(currentFrame);
}), System.Windows.Threading.DispatcherPriority.Render, null);
Dispatcher.BeginInvoke((Action)(() =>
{
SkinImage.Source = BitmapSourceConvert.ToBitmapSource(skin2);
}), System.Windows.Threading.DispatcherPriority.Render, null);
I hope this helps I will at some point neaten up the code I uploaded,
Cheers

image quality is blurry

I have a situation where I want to convert some XAML to an image, so I created a RichTextBox and then took the image of it. Now problem is that words in image is blurred, any idea how I might be able to fix it?
public System.Drawing.Bitmap ConvertXamltoImage(string XamlString, int Width, int Height)
{
RichTextBox AdContentRichTextBox = new RichTextBox() { Width = Width, Height = Height };
AdContentRichTextBox.BorderThickness = new Thickness(0);
XmlReader _XmlReader = XmlReader.Create(new StringReader(XamlString));
AdContentRichTextBox.Document = XamlString;
var size = new Size(Width, Height);
AdContentRichTextBox.Measure(size);
AdContentRichTextBox.Arrange(new Rect(size));
RenderTargetBitmap bmp = new RenderTargetBitmap(Width, Height, 300, 300, PixelFormats.Pbgra32);
bmp.Render(AdContentRichTextBox);
DrawingVisual _drawingVisual = new DrawingVisual();
using (DrawingContext _drwaingContext = _drawingVisual.RenderOpen())
{
VisualBrush _visualBrush = new VisualBrush(AdContentRichTextBox);
}
PngBitmapEncoder _png = new PngBitmapEncoder();
_png.Frames.Add(BitmapFrame.Create(bmp));
System.Drawing.Bitmap _tempBitmap = null;
using (Stream _fileStream = new MemoryStream())
{
_png.Save(_fileStream);
_tempBitmap = new System.Drawing.Bitmap(_fileStream);
_fileStream.Flush();
}
return _tempBitmap;
}

Hmmmm..there could be lots of things all interacting here:
1st
"Grayscale fall back - if ClearType is disabled or one is rendering text in certain situations where the ClearType algorithm cannot be run, WPF will use a grayscale rendering algorithm to antialias the rendered text."
Rendering Text to a RenderTargetBitmap seems to be one of those situations....(the renderer switches from a hardware to a software path).
2nd
In addition NET 4 switched the default scaling algorithm from high-quality (Fant) to low-quality (Bi-Linear).....now that shouldn't come into play here as it doesn't look like you are scaling the bitmap in any way...but you never know what's going on inside. It's possible to switch the scaler back to the higher quality one.
http://www.olsonsoft.com/blogs/stefanolson/post/Workaround-for-low-quality-bitmap-resizing-in-WPF-4.aspx
3rd
You may need to take into account the parent container of the RichTextBox...see last link below, mentions it can distort the font rendering.
Problems with rendering text as bitmaps using WPF
Some ideas on how to work around this are:
render the RichTextBox at a higher resolution e.g. 600dpi, and then scale down the bitmap (probably will make no difference)
capture the screen....difficult or not practical if your visual is offscreen/obscured, etc.
See related links:
http://windowsclient.net/wpf/white-papers/wpftextclarity.aspx
WPF RenderTargetBitmap downscaling text ClearType to GreyScale
WPF RenderTargetBitmap downscaling TextRenderMode to GreyScale
WPF text rendering inconsistencies