Develop Reference

WPF Image control masked with a container same as polygon

I placed a PNG Image with some transparent areas on my window. It's over a Button control, now when i want to click on My Button, it has some UnClickable points because transparent space of image is over it.
Now, i want mask my image with another control like polygon or use a good way to solve my problem.
I tested following way, but it didn't fill all of the polygon area by image. It is like a rectangle image inside a polygon:
<Polygon
Points="0 50,50 60,58 50,60 50,85 50,95 65,112 65,130,40135,40135 90,0 90"
Stroke="Purple"
StrokeThickness="2" Margin="0,0,146,99" HorizontalAlignment="Right" Width="139" VerticalAlignment="Bottom" Height="99">
<Polygon.Fill>
<ImageBrush ImageSource="/Resources/myImage.png" AlignmentY="Top" Stretch="None" />
</Polygon.Fill>
</Polygon>
Result is like this:
.............................................................
But I want something like this:
......................................

Make the fill image of your polygon rectangular and use Stretch=None or Fill or....

Scrolling problems when using ScaleTransform in Panorama/Pivot/RadSlideView item

I'm trying to implement zoom-functionality in a RadSlideView ItemTemplate. I'm doing this by using a ViewportControl with a Canvas and then applying a RenderTransform (ScaleTransform) to a StackPanel in the Canvas. Similar to the SDK-sample found here.
The problem I have is that the ScaleTransform seems to be affecting the swipe-gesture used to change item in the SlideView/Panorama/Pivot control. E.g. if the ScaleTransform is set to 0.1 it seems like I only need to swipe 1/10th of the length to change item compared to using a ScaleTransform of 1.0.
I found that if I set IsHitTestVisible to false on the ItemTemplate the swiping works like I want. But this is not a solution since I sometimes need to be able to pan the content vertically while still being able to change item by swiping horizontally.
So my question is how can I solve this?
For reference the XAML looks like this:
<Controls:RadSlideView Name="SlideView" ItemsSource="{Binding Pages}" IsLoopingEnabled="False" SelectionChanged="RadSlideView_SelectionChanged" CacheMode="BitmapCache" ManipulationStarted="SlideView_ManipulationStarted" ManipulationCompleted="SlideView_ManipulationCompleted" ManipulationDelta="SlideView_ManipulationDelta">
<Controls:RadSlideView.ItemTemplate>
<DataTemplate>
<ViewportControl x:Name="SlideViewViewport" ViewportChanged="SlideViewViewport_ViewportChanged" Loaded="SlideViewViewport_Loaded">
<Canvas>
<StackPanel>
<Image Source="{Binding Image}" Stretch="Fill" Width="{Binding ElementName=SlideView, Path=DataContext.PageWidth}" Height="{Binding ElementName=SlideView, Path=DataContext.PageHeight}" CacheMode="BitmapCache"/>
<StackPanel.RenderTransform>
<ScaleTransform x:Name="xform"/>
</StackPanel.RenderTransform>
</StackPanel>
</Canvas>
</ViewportControl>
</DataTemplate>
</Controls:RadSlideView.ItemTemplate>
I have also looked at Teleriks RadPanAndZoom-control to avoid implementing my own zoom-functionality, but since I sometimes need to place two pictures side by side and zoom them as if they were one I don't think I can use it.

The problem is that ScaleTransformation scales your picture, but doesn't change it's height and width. Only if Height And Width are overflowing scrollviewer you can scroll the content

Is it possible to set a border to overlay (like in photoshop)

I am having a quite exotic question:
I am currently working on a "borderless" WPF Application. I successfully removed the standard windows window controls and added my own. Now I wanted to add a border to the programm. But I don't want the border to have specifc color, I want it to be in some kind of overlay mode like when you set a layer in photoshop to overlay. You can see what I mean in an example:
I really want it to look like on the left. But unfortunately I really have no idea how.
Basically what the overlay does is that it takes the background color and it makes it a bit darker.
Do you have any suggestions what I could do?
Edit: Here is a better picture of the effect
Photoshop Mookup2 http://img.xrmb2.net/images/243147.png
Edit2 : So, as a short explanation because it may not be as clear as I have hoped: I am not talking about a semi-transparency. I know how to do that. The right box in both images uses that. It has a black-semitransparent look. While on the left I set the border to "overlay" mode. As you can see it gets darker but also a bit stronger in color.

How about using the Transparent brush?:
<Border BorderBrush="Transparent" BorderThickness="5">
...
</Border>
UPDATE >>>
Oh, hold on... I see what you want... try this instead with a semi opaque `brush:
<Border BorderBrush="3F000000" BorderThickness="5">
...
</Border>
You can adjust the darkness of the Border, by changing the first two hexadecimal characters: 3F.
UPDATE >>>
I believe that this is the correct solution. As I said last:
You can adjust the darkness of the Border, by changing the first two hexadecimal characters
So just try different values until you get the right balance of opacity. Start with hardly visible black and then increase the opacity until you get it right:
<Border BorderBrush="08000000" BorderThickness="5">
...
</Border>
...
<Border BorderBrush="0F000000" BorderThickness="5">
...
</Border>
...
<Border BorderBrush="1F000000" BorderThickness="5">
...
</Border>
...
<Border BorderBrush="2F000000" BorderThickness="5">
...
</Border>
If none of these values look quite right still, then use a semi-opaque white instead:
<Border BorderBrush="2FFFFFFF" BorderThickness="5">
...
</Border>

Draw text on a shape in a wpf

Some of you maybe find this question dull but I am still not deeply accustomed to wpf drawing. I want to add formatted text on a Rectangle which moves around on a canvas and I have got a hint to override the UIElement.OnRender method. However I do not know if I should override the canvas class or the Shape class. In any correct case, to what refers the drawingContext parameter of the method as described in the example: http://msdn.microsoft.com/en-us/library/bb613560.aspx#FormattedText_Object ?
Is the text ultimately assigned to the shape or is it a visual temporary effect that cannot move along with the shape on the canvas?
Is there any further effective means of drawing text on a shape?

You can draw Text on top of a Rectangle by placing both controls in a parent container that allows controls to overlap, such as a Grid or a Canvas
<Grid>
<Rectangle Fill="Red" Stroke="Black"
HorizontalAlignement="Stretch" VerticalAlignment="Stretch" />
<Label Content="Test"
HorizontalAlignment="Center" VerticalAlignment="Center" />
</Grid>
You can then apply whatever formatting you want to the Label, the Rectangle, and you can move the group around by setting the positioning of the Grid

Rachel's answer is correct, although you can extend it a bit, have some UserControl defined as:
And in the codebehind define 1. Label:String DependencyProperty, Shape:UIElement DependencyProperty.
Handle the Shape's change event and call:
private void UpdateShape()
{
grdShapeContainer.Children.Clear();
if(this.Shape != null)
{
grdShapeContainer.Children.Add(this.Shape);
}
}
This way you will be able to make things dynamic.
Regards,
Artak

You might also want to look into ZIndex property which can be set on objects like Grid (<Rectangle Background="Black" Grid.ZIndex = 99 /> for instance would put it overtop other items) which useful for making things like "loading" screens.

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!