Develop Reference

How to get a ScrollViewer to zoom in to see individual pixels?

I'm making an app for Windows 8.1 where it is important to be able to zoom in and examine images in detail. If I just open up the bitmap and zoom in it looks like.
However when I load the image into my app and use the ScrollViewer to zoom in I get.
As it appears to be trying to interpolate pixel values for some sort of anti-aliasing.
How can I get it so that when I zoom in it shows (as best it can) the exact pixels of the image? In particular I'm using the image as the background to a canvas which is contained in a scroll viewer.
I've looked around on here and MSDN and found a pair of related questions, but as yet they don't seem to have solved my exact problem.
A discussion on WPF
A similar issue with a canvas
Older related question on pixel art
A way to use bitmap encoding (which I couldn't get to work)
Similarly phrased question

There is no easy way to go about this, your best option is to use DirectX to render the image much larger so that you can mitigate the effect of WinRT automatically interpolating pixel values.
As someone explained on MSDN and based on this outstanding request I can't see any other way to accomplish this.
Use Win2D
Win2D is a DirectX inter-op library for WinRT. With this you can render the image at a much larger size, and then set the default zoom level for the scrollViewier to be very small. Because of this when you zoom in it will appear to be that you can see the individual pixels without any fuzzy/blurry interpolation because you will actually be seeing groups of 64 pixels or so all as one color. I couldn't find any way to actually override what kind of interpolation gets done so this seems to be the best method.
Download Win2D as a NuGet package using Visual Studio, Win2D's
quickstart guide does a good job explaining some of the setup
Set up your canvas and the draw event and use the DrawImage function to render the image larger
<ScrollViewer x:Name="Scroller" ZoomMode="Enabled"
MinZoomFactor="0.1" MaxZoomFactor="20">
<canvas:CanvasControl x:Name="canvas" Draw="canvas_Draw" CreateResources="create"/>
</ScrollViewer>
In the canvas_draw function.
canvas.Width = original.Width * 10;
canvas.Height = original.Height * 10;
args.DrawingSession.DrawImage(bitmap,new Rect(0,0,original.Width*10,original.Height*10), new Rect(0,0,original.Width,original.Height), 1.0f, CanvasImageInterpolation.NearestNeighbor);
Make sure to set your canvas to be larger as well
In your code behind set the default zoom of your ScrollVieiwer to be appropriate so your image appears to be the same size.
In the page constructor
Scroller.ZoomToFactor (0.1f);
Other Ways Which I Looked Into and Didn't Work
Making the canvas very large and using BitmapEncoder/BitmapDecoder with the interpolation mode set to NearestNeighbor, this introduced lots of visual artifacts even when scaled to a power of 2 size
Render options only appear to be usable in WPF and not WinRT
It may also be possible to use some image manipulation library to simply make the bitmap 10x or so as large and then use that, but I ended up using Win2D instead.

How to display SkeletonStream on a DepthStream or ColorStream Kinect Wpf

I would like to know how to overlay two Image objects in Wpf. I've made two streams which output a video, one for bones and another just a normal video. Now I would like to add them together, so the skeleton would be displayed on the color video.
A part of my XAML code is
<Grid Name="layoutGrid">
<Grid Name="VideoGrid" ClipToBounds="True" Background="AliceBlue">
<Image Name="ColorImage" Width="640" Height="480"/>
<Image Name="SkeletalImage" Width="640" Height="480"/>
<Canvas Background="Transparent"/>
</Grid>
<StatusBar VerticalAlignment="Bottom" HorizontalAlignment="Center">
<Button Name="Button1" Content="Skeleton Only" Width="120"/>
</StatusBar>
</Grid>
When I do this, only the Skeletal image is displayed and if I switch the both Images then the color image is shown. It seems like Canvas background doesn't do the trick (to make the black part of skeletal image transparent)

I thought the problem was in my XAML code but it was actually at drawing the transparent background to set the render size. The background for skeleton image was black
dc.DrawRectangle(Brushes.Black, null,
new Rect(0.0, 0.0, RenderWidth, RenderHeight));
instead of transparent
dc.DrawRectangle(Brushes.Transparent, null,
new Rect(0.0, 0.0, RenderWidth, RenderHeight));
that fixed my problem.
Thanks though

I've tried overlaying Skeletal onto color or depth on a canvas, but it never worked out. Instead, when I looked at the Kinect Explorer sample application in the SDK 1.6.0, they overlay using a grid. Unfortunately, I have not learned that much yet, but they used a grid for the color and depth, and a canvas for the skeletal tracking. I can post a snippet if it helps. Good luck!

You are asking basically two different questions: 1) How to display SkeletonStream on a DepthStream, which is very easy, 2) How to display SkeletonStream on a ColorStream, which is still easy but a little more complicated.
Answer to Question 1) The XYZ Vectors of the joints in the skeletal streams are in the same coordinate system as the Depth Stream. So if you plot the Deapth Stream as a quadratic mesh using the focal length of the depth camera from the Kinect SDK, you can plot the skeleton as a line plot in the same coordinate system. The source code that implements exactly what you want to do in OpenGL is available here that will give you an idea how to implement this in wpf.
Answer to Question 2) The video camera has a different field of view from the depth camera. To display the skeleton stream to the ColorStream you need first to map the XYZ vectors of the joints in the skeletal streams to the coordinate system of the depth stream and then draw first the video frame in the background and the skeleton as a line plot on the front.
You can easily do the mapping using the U-V texture coordinates given by the Kinect SDK. See how you can get the UV here.

Manipulating Images in Windows Surface 2.0 (rotation)

I am using c# wpf for windows surface 2.0.
I have been working with a set of images that i import in the xmpl file.
I found some examples for text, but for the images they used GDI+ to manipulate images and animate them, but I do not want that.
The main thing that I want to do now is to rotate(transform rotate) an image and show that it is rotating.
Here is how I am addressing the images:
Canvas.SetTop(image1, 0);
Canvas.SetLeft(image1, 200);
Any help would be much appreciated.
Thank you.

If you want to rotate your image automatically and without user interaction, check Clemens' answer. However if you want to rotate with touch manipulations, I find it easy to put the image in a ScatterViewItem like so:
<s:ScatterView>
<s:ScatterViewItem CanMove="False" CanScale="False">
<s:ScatterViewItem.Background>
<ImageBrush ImageSource="yourImage.png" Stretch="UniformToFill"/>
</s:ScatterViewItem.Background>
</s:ScatterViewItem>
</s:ScatterView>
Of course, you have the overhead of having to put in a ScatterView and its content

Your question is not very specific and there are a lot of ways to animate the rotation of an image.
A simple approach would be to assign a RotateTransform to the RenderTransform of your Image controls and then animate the Angle property of these RotateTransforms.
<Image x:Name="image" Source="..."
RenderTransformOrigin="0.5,0.5">
<Image.RenderTransform>
<RotateTransform/>
</Image.RenderTransform>
</Image>
Start the animation in code like this:
var transform = (RotateTransform)image.RenderTransform;
var animation = new DoubleAnimation(360, TimeSpan.FromSeconds(5));
transform.BeginAnimation(RotateTransform.AngleProperty, animation);
You may start reading about animations in WPF in the Animation Overview article on MSDN. The Transforms Overview article may also be helpful.

Kinect show Depth Image in Full Screen

Is there a way to show Kinect Depth Image into Full Screen mode? I'm using C# and WPF, the OpenNI C++ example able to show the dept image in full size with out any stretch occur, but when I use WPF, the image gets stretch out.
Currently I'm getting resolution of 640X480, but I want to display it into any screen size or maybe TV. My laptop is 1280X768 but when u make the image full size it get stretced.
Thanks in advance.

As far as I know the hardware resolution of the Kinect cameras is 640 x 480 so there is no way to increase that without stretching.
In WPF it is possible to scale the image in proportion so the dots of the image remain square.
<Image Source="..." Stretch="Uniform" />
or not scale at all:
<Image Source="..." Stretch="None" />
See Stretching Images under Displaying Images in WPF

Image in WPF getting Blurry

I am developing an application in WPF using C#. I am putting Images in a WrapPanel and showing inside a Grid with one more Border and using images in Buttons also. Problem is my Image control loosing its quality. I am not able to post my image here so I am simply describing here.
I used SnapsToDevicePixels="True" for the images but still it looks blurry.
Updated:
Here I shared the Image below:

I think what Markus told is the one way to resolve your issue and try by adding one more property in it RenderOptions.EdgeMode="Aliased" for each image I mean :
<Image Source="/LoginPanel;component/Icons/icoLogin.ico"
RenderOptions.BitmapScalingMode="NearestNeighbor"
RenderOptions.EdgeMode="Aliased"/>
if you still not able to fix your problem then you can refer this http://blogs.msdn.com/b/dwayneneed/archive/2007/10/05/blurry-bitmaps.aspx to create a custom Bitmap class and apply on all Images which are creating trouble for you.
You can also see this Stack Overflow Question

SnapsToDevicePixels seems not working for bitmaps.
The NearestNeighbor options actually converts the bitmap and will end up with different one to the original bitmap.
In WPF 4, a property "UseLayoutRounding" on the FrameworkElement is introduced to solve this problem.
By setting this property to True on your root element, such as Window will align children elements on the edges of pixels.
<Window UseLayoutRounding="True">...</Window>

This works for me
<Image Source="/LoginPanel;component/Icons/icoLogin.ico"
RenderOptions.BitmapScalingMode="NearestNeighbor"</Image>
Set RenderOptions.BitmapScalingMode="NearestNeighbor" for each image. Alternatively see this question here on StackOverflow.
Edit:
Here is my sample code
<Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="661">
<WrapPanel>
<Button VerticalAlignment="Center">
<Image Source="/WpfApplication1;component/icoChip32x32.ico"
RenderOptions.BitmapScalingMode="NearestNeighbor" Stretch="None"></Image>
</Button>
<Button VerticalAlignment="Center">
<Image Source="/WpfApplication1;component/icoChip32x32.ico"
RenderOptions.BitmapScalingMode="NearestNeighbor" Stretch="None"></Image>
</Button>
<Button VerticalAlignment="Center">
<Image Source="/WpfApplication1;component/Presentation-Edit.png"
RenderOptions.BitmapScalingMode="NearestNeighbor" Stretch="None"></Image>
</Button>
<Button VerticalAlignment="Center">
<Image Source="/WpfApplication1;component/Presentation-Edit.png"
RenderOptions.BitmapScalingMode="NearestNeighbor" Stretch="None"></Image>
</Button>
</WrapPanel>
</Window>
And this is my result:

Use UseLayoutRounding="True" property on the parent element if image is used as a content. In your case it is the Button.

I ran into a blurriness issue with image backgrounds caused by scaling and the solution was much simpler than you may think. While at first I wondered if it was being scaled up to a power-of-two texture size, the scaling actually matched the ratio of System DPI (96) : Image DPI (72, which is the default for many editors). If you adjust the image to 96 DPI it should display pixel-perfect with the default Windows settings.
EDIT: Tried an image with high detail contrast and it is slightly softened.

WPF doesn't use concrete pixel values for sizes and positioning, so that it can scale well with DPI.
This can lead to a problem where it tries to use a position that doesn't correspond to a discrete on-screen pixel; some of the image pixels are rendered over multiple on-screen pixels which we see as blurring.
UseLayoutRendering=true with SnapToDevicePixels=false should solve this issue. You also need to set it at the main window level too, so that the calculations cascade down to the image level.
You can try this out by creating a simple WPF application with one window, and your images. Setting the image margin to be something silly like (10.452, 0.736, 0, 0) will lead to blurring. This goes away with UseLayoutRendering=true on the image.
If you then set the margin again in your window's constructor after InitializeComponent(), it is blurry regardless of whether you set UseLayoutRendering=true on the image, since the calculations to line up with on-screen pixels were made before you then moved the image to a location which doesn't match up with these.
I'm not entirely sure what the difference is between UseLayoutRendering and SnapToDevicePixels - I think it is just the time that the calculations are made. UseLayoutRendering seems to be preferable for images.
Stretching/squashing an image from its original size can also lead to blurring problems.

I had the same Problem, but in my case I've downloaded Icons and found out, that they all had wrong DPI too... 110,56 and 116,xx and 95,99 etc...
When i changed the DPI to 96 for all, everything was fine!