Develop Reference

How to bind PathGeometry objects in MVVM

Imagine an application where the user can type in some text and based on the text input different symbols are shown on an image.
I am looking for a way generate a list of Path objects and bind this list in XAML to show the path objects on top of another path-image.
I.e. I have a simple image of a house, the user type in text like:
"ball on roof, flower in window, shovel in garden"
In the ViewModel I will analyze this text and generate a path Circle for the ball, a path Star for the flower and a path Square for the shovel.
I think these objects should be put in a List and in XAML bind to this list.
The "house" is drawn like this:
<Border Grid.Column="1" CornerRadius="10" BorderBrush="Black" BorderThickness="0.3" Margin="5,0,0,0" Grid.RowSpan="2" Padding="5">
<Viewbox xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Stretch="Uniform">
<Grid RenderTransformOrigin="0.5,0.5">
<Grid.RenderTransform>
<TransformGroup>
<ScaleTransform ScaleY="-1" ScaleX="1"/>
<SkewTransform AngleY="0" AngleX="0"/>
<RotateTransform Angle="0"/>
<TranslateTransform/>
</TransformGroup>
</Grid.RenderTransform>
<Path Fill="Black" Data="{StaticResource Path1}"/>
<Path Fill="Black" Data="{StaticResource Path2}"/>
<Path Fill="Black" Data="{StaticResource Path3}"/>
<Path Fill="Black" Data="{StaticResource Path4}"/>
...
</Grid>
</Viewbox>
</Border>
After the all the "Path" I imagine I would use a CombinedGeometry and bind to the VM List. But I am not sure about this part.

How to move an image horozontally in UWP with C#?

I am transitioning from Windows forms to UWP, and as an exercise want to move an image across the screen. In Forms its easy using image.Left, but for the life of me I can't find a way in UWP.
I tried wrapping it in Canvas, as suggested elsewhere,
<Canvas
x:Name="cDog1"
Grid.Row="1"
Margin="29,0,0,0"
HorizontalAlignment="Left"
VerticalAlignment="Top">
<Image
x:Name="Dog1"
Canvas.Left="0"
Source="Assets/images/dog.png"
Stretch="None" />
</Canvas>
But still can't get back a Canvas.Left that can be changed.
In the materials I read they speak of a SetLeft, yet that isn't an option.
Solved!
<Canvas
x:Name="cDog1"
Grid.Row="1"
Margin="29,0,0,0"
HorizontalAlignment="Left"
VerticalAlignment="Top">
<Image
x:Name="Dog1"
Canvas.Left="0"
Source="Assets/images/dog.png"
Stretch="None" >
<Image.RenderTransform>
<TranslateTransform x:Name="MoveDog1" X="0" Y="0"/>
</Image.RenderTransform>
</Image>
</Canvas>
From https://social.msdn.microsoft.com/Forums/sqlserver/en-US/4ed8bbf8-5a63-4ef9-a9e5-ddcb310ed865/uwpchow-do-i-move-something-with-a-button-press?forum=wpdevelop

How to use the XAML dictionary that Syncfusion Metro Studio produces

For resolution independence we want scaling art. Ok, so a common source for that mentioned on stack is Syncfusion Metro Studio.
Metro Studio 2 produces this for XAML:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Viewbox x:Key="error">
<Grid Width="64" Height="64" Visibility="Visible">
<Grid Visibility="Visible">
<Rectangle Fill="#FFD21818" Visibility="Visible" />
<Ellipse Fill="#FFD21818" Visibility="Collapsed" />
<Path Data="M50.5,4.7500001C25.232973,4.75 4.75,25.232973 4.7500001,50.5 4.75,75.767029 25.232973,96.25 50.5,96.25 75.767029,96.25 96.25,75.767029 96.25,50.5 96.25,25.232973 75.767029,4.75 50.5,4.7500001z M50.5,0C78.390381,0 101,22.609621 101,50.5 101,78.390381 78.390381,101 50.5,101 22.609621,101 0,78.390381 0,50.5 0,22.609621 22.609621,0 50.5,0z" Stretch="Fill" Fill="#FFD21818" Visibility="Collapsed" />
</Grid>
<Path Data="F1M54.0573,47.8776L38.1771,31.9974 54.0547,16.1198C55.7604,14.4141 55.7604,11.6511 54.0573,9.94531 52.3516,8.23962 49.5859,8.23962 47.8802,9.94531L32.0026,25.8229 16.1224,9.94531C14.4167,8.23962 11.6511,8.23962 9.94794,9.94531 8.24219,11.6511 8.24219,14.4141 9.94794,16.1198L25.8255,32 9.94794,47.8776C8.24219,49.5834 8.24219,52.3477 9.94794,54.0534 11.6511,55.7572 14.4167,55.7585 16.1224,54.0534L32.0026,38.1745 47.8802,54.0534C49.5859,55.7585 52.3516,55.7572 54.0573,54.0534 55.7604,52.3477 55.763,49.5834 54.0573,47.8776z" Stretch="Uniform" Fill="#FFFFFFFF" Width="36" Height="36" Margin="0,0,0,0" RenderTransformOrigin="0.5,0.5">
<Path.RenderTransform>
<TransformGroup>
<TransformGroup.Children>
<RotateTransform Angle="0" />
<ScaleTransform ScaleX="1" ScaleY="1" />
</TransformGroup.Children>
</TransformGroup>
</Path.RenderTransform>
</Path>
</Grid>
</Viewbox>
</ResourceDictionary>
So far so good, just merge this into the project resources. But how to consume this?
using viewbox in ResourceDictionary file has an answer that lets you change the ViewBox to DataTemplate in the ResourceDictionary and then use a converter to display it as a button's ContentTemplate. That is ok for Button based stuff, but what if I just need the icon itself. How do I go from ViewBox in a resource dictionary to somehow including it in lets say a grid in XAML?

You can use it as Content for any ContentControl Directly,in case if you just want the icon in Grid,try like below,
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Viewbox x:Key="error">
<Grid Width="64" Height="64" Visibility="Visible">
<Grid Visibility="Visible">
<Rectangle Fill="#FFD21818" Visibility="Visible" />
<Ellipse Fill="#FFD21818" Visibility="Collapsed" />
<Path Data="M50.5,4.7500001C25.232973,4.75 4.75,25.232973 4.7500001,50.5 4.75,75.767029 25.232973,96.25 50.5,96.25 75.767029,96.25 96.25,75.767029 96.25,50.5 96.25,25.232973 75.767029,4.75 50.5,4.7500001z M50.5,0C78.390381,0 101,22.609621 101,50.5 101,78.390381 78.390381,101 50.5,101 22.609621,101 0,78.390381 0,50.5 0,22.609621 22.609621,0 50.5,0z" Stretch="Fill" Fill="#FFD21818" Visibility="Collapsed" />
</Grid>
<Path Data="F1M54.0573,47.8776L38.1771,31.9974 54.0547,16.1198C55.7604,14.4141 55.7604,11.6511 54.0573,9.94531 52.3516,8.23962 49.5859,8.23962 47.8802,9.94531L32.0026,25.8229 16.1224,9.94531C14.4167,8.23962 11.6511,8.23962 9.94794,9.94531 8.24219,11.6511 8.24219,14.4141 9.94794,16.1198L25.8255,32 9.94794,47.8776C8.24219,49.5834 8.24219,52.3477 9.94794,54.0534 11.6511,55.7572 14.4167,55.7585 16.1224,54.0534L32.0026,38.1745 47.8802,54.0534C49.5859,55.7585 52.3516,55.7572 54.0573,54.0534 55.7604,52.3477 55.763,49.5834 54.0573,47.8776z" Stretch="Uniform" Fill="#FFFFFFFF" Width="36" Height="36" Margin="0,0,0,0" RenderTransformOrigin="0.5,0.5">
<Path.RenderTransform>
<TransformGroup>
<TransformGroup.Children>
<RotateTransform Angle="0" />
<ScaleTransform ScaleX="1" ScaleY="1" />
</TransformGroup.Children>
</TransformGroup>
</Path.RenderTransform>
</Path>
</Grid>
</Viewbox>
</ResourceDictionary>
<Grid>
<ContentControl Content="{StaticResource error}"/>
</Grid>
if you are intend to use the same resource in multiple location,please set x:Shared attribute as false as below,
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Viewbox x:shared="false" x:Key="error">
.......
</Viewbox>
</ResourceDictionary>

I did a similar thing in one of my projects using Syncfusion Metro Studio. I found wrapping the image in a ViewBox caused a number of annoyances. I ended up using the image alone, and then embedded it into a Path where I wanted to use the image.
I found it a lot more flexible than trying to squeeze a ViewBox into xaml.
How I did it:
There is a type Geometry, which allows you to define a Bezier path as a resource:
<Geometry x:Key="Keyboard">M48.537998,24.254L57.365002,24.254 57.365002,30.875 48.537998,30.875z M17.642,24.254L46.332001,24.254 46.332001,30.875 17.642,30.875z M6.6760006,24.254L15.504,24.254 15.504,30.875 6.6760006,30.875z M50.744999,15.426L57.365002,15.426 57.365002,22.047001 50.744999,22.047001z M41.986,15.426L48.606998,15.426 48.606998,22.047001 41.986,22.047001z M33.09,15.426L39.709999,15.426 39.709999,22.047001 33.09,22.047001z M24.261999,15.426L30.882999,15.426 30.882999,22.047001 24.261999,22.047001z M15.435,15.426L22.056,15.426 22.056,22.047001 15.435,22.047001z M6.6070004,15.426L13.229,15.426 13.229,22.047001 6.6070004,22.047001z M50.744999,6.599L57.365002,6.599 57.365002,13.219 50.744999,13.219z M41.986,6.599L48.606998,6.599 48.606998,13.219 41.986,13.219z M33.09,6.599L39.709999,6.599 39.709999,13.219 33.09,13.219z M24.261999,6.599L30.882999,6.599 30.882999,13.219 24.261999,13.219z M15.435,6.599L22.056,6.599 22.056,13.219 15.435,13.219z M6.6070004,6.599L13.229,6.599 13.229,13.219 6.6070004,13.219z M4.47015,4.4635506L4.47015,33.242199 59.6413,33.242199 59.6413,4.4635506z M1.3333101,0L62.666698,0C63.403,0,64,0.59634399,64,1.3333397L64,36.166698C64,36.903702,63.403,37.5,62.666698,37.5L1.3333101,37.5C0.59704602,37.5,0,36.903702,0,36.166698L0,1.3333397C0,0.59634399,0.59704602,0,1.3333101,0z</Geometry>
Once you have a geometry resource you can use it in Path.Data. In this example the border is the bounds of the image 32x32 pixels. Then you can use the Border and use it in a Grid as you would with any other control.
<Border Width="32" Height="32">
<Path Data="{StaticResource Keyboard}" Fill="White" Stretch="Uniform" RenderTransformOrigin="0.5, 0.5">
</Path>
</Border>
This technique also allows you to bind the properties as needed. I.e. Fill to a color, and have it change dynamically.

Simply import the output from Metro Studio into Expression Blend
-> Design View
Select icon and click 'Tools' -> Make Brush Resource -> MakeDrawingBrush
Then Blend will convert the icon for use anywhere in your app

cannot draw shape in canvas

I have a canvas in xaml defined as following. However adding a rectangle in it doesn't show any thing.
<lib:DrawingCanvas x:Name="drawingCanvas" Background="White" AllowDrop="True">
<Rectangle Margin="20,20,20,20" Fill="Black" Stroke="White" Width="100" Height="100">
</Rectangle>
</lib:DrawingCanvas>
Can you give me some hints here?
Thanks.

You're not using a Canvas, you're using a "DrawingCanvas", so I can't speak for any differences. But assuming it derives from Canvas:
You need to set the attached properties for the Rectangle. These are Canvas.Left or Canvas.Right, in addition to Canvas.Top or Canvas.Bottom.
For example:
<Rectangle Canvas.Left="50" Canvas.Top="100" Width="100" Height="100" Fill="Black" />

Prevent image crop when rotating using transform

I'm binding following XAML to RotateAngle property and it works great with one "but". Image displays cropped. Image control doesn't seem to be refreshing/resizing after rotation. Is there any way to force resize on image and scrollviewer?
<ScrollViewer Grid.Row="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" VerticalScrollBarVisibility="Auto" BorderThickness="0" HorizontalScrollBarVisibility="Auto">
<Image
VerticalAlignment="Stretch" HorizontalAlignment="Stretch"
Source="{Binding Input, Converter={StaticResource ByteArrayToBitmapConverter}}"
RenderTransformOrigin="0.5,0.5">
<Image.RenderTransform>
<RotateTransform Angle="{Binding RotateAngle}"></RotateTransform>
</Image.RenderTransform>
</Image>
</ScrollViewer>

http://www.silverlight.net/content/samples/sl3/toolkitcontrolsamples/run/default.html
Go to this page, there is a control called LayoutTransformer. See the sample of that control. It handles rotation, scaling and skewing of images, textbox, listbox, etc.
You will get the code there.
Hope that helps.!

You can try:
<Image x:name="ctrl"
VerticalAlignment="Stretch" HorizontalAlignment="Stretch"
Source="{Binding Input, Converter={StaticResource ByteArrayToBitmapConverter}}"
RenderTransformOrigin="0.5,0.5">
<Image.RenderTransform>
<RotateTransform Angle="{Binding DataContext.RotateAngle, ElementName=ctrl}"></RotateTransform>
</Image.RenderTransform>
</Image>

Or you can use:
<Image
VerticalAlignment="Stretch" HorizontalAlignment="Stretch"
Source="{Binding Input, Converter={StaticResource ByteArrayToBitmapConverter}}"
RenderTransformOrigin="0.5,0.5">
<Image.RenderTransform>
<RotateTransform Angle="{Binding DataContext.RotateAngle, RelativeSource={RelativeSource Self}}"></RotateTransform>
</Image.RenderTransform>
</Image>

Assuming you want to scale your image down to fit the original image space, you could use my CalculateConstraintScale method from here:
Silverlight Rotate & Scale a bitmap image to fit within rectangle without cropping to scale the image down based on the rotation.
Click here for a working testbed app created for that answer (looks like the image below):