Develop Reference

Copying rotated image to existing image in C# code-behind

I am trying to copy a rotated image to an existing image in the code-behind.
Here are my 2 images:
<Image x:Name="tempImage1" Source="Images/firstImage.jpg" Stretch="None" VerticalAlignment="Center" HorizontalAlignment="Center" />
<Image x:Name="myImage2" Source="Images/secondImage.jpg" Stretch="None" VerticalAlignment="Center" HorizontalAlignment="Center" />
And the rotation in the code-behind:
RotateTransform rt = new RotateTransform(-theta, 200, 300);
tempImage1.RenderTransform = rt;
myImage2.Source = tempImage1.Source;
I know I'm not doing it right (still very new to this). Could someone please help point me in the right direction? The result I'm looking for is to have myImage2 have show tempImage1 in its rotated form, not the original source.

Using a RenderTargetBitmap solved the issue for me.
With images tempImage1 and myImage2 in your XAML:
RenderTargetBitmap rtb = new RenderTargetBitmap(_width, _height, 96, 96, PixelFormats.Default);
rtb.Render(tempImage1);
myImage2.Source = rtb;
The above is done with the assumption that tempImage1 has already been rotated and transformed.

Well if you do that you must know that the first image would be visible as it is in the background well I simply rotated as per your question in an angle of 30 degree the XAML remains same the new C# code is
RotateTransform rt = new RotateTransform();
rt.Angle = 30;
tempImage1.RenderTransform = rt;
myImage2.Source = tempImage1.Source;

Rectangle UI on Windows Phone app?

I have a xaml page that I put a rectangle on a grid (grid covers whole screen). How do I go about getting the coordinates of the Rectangle's upper left corner?
Xaml class:
<Page
x:Class="JunkyJunk.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:JunkyJunk"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Canvas>
<Rectangle x:Name="TestRectangle"
Fill="#FFF4F4F5"
HorizontalAlignment="Left"
Height="100"
Stroke="Black"
VerticalAlignment="Top"
Width="100"
Loaded="TestRectangle_Loaded" Canvas.Left="137" Canvas.Top="245"/>
</Canvas>
So lets just say I just place this rectangle onto a canvas (changed it from a grid). How would I get the coordinates of the rectangle's upper left corner?
Thanks

Figured it out.
double x = Canvas.GetLeft(TestRectangle);
double y = Canvas.GetTop(TestRectangle);

You can use a GeneralTransform to convert a point or rectangle from one UIElement's coordinate system to another's.
The rectangle's top left coordinates will always be 0,0 in the rectangle's coordinates, so if you translate that to your canvas' coordinates then you can look at the new value to see where the Rect is.
This will work with any two UIElements, so you could keep your Grid and not have to rely on Canvas.Left and Canvas.Top.
// Rectangle's bounds in its own coordinates
Rect testRectLocalBounds = new Rect(0, 0, TestRectangle.ActualWidth, TestRectangle.ActualHeight);
// Transforms from TestRectangle's to this page's and to TestCanvas' coordinates
GeneralTransform transformToPage = TestRectangle.TransformToVisual(this);
GeneralTransform transformToCanvas = TestRectangle.TransformToVisual(TestCanvas);
// TestRectangle's boundaries in the Page's and Canvas' coordinates
Rect testRectPageBounds = transformToPage.TransformBounds(testRectLocalBounds);
Rect testRectCanvasBounds = transformToCanvas.TransformBounds(testRectLocalBounds);
Debug.WriteLine("Rect relative to page: {0} to canvas: {1}", testRectPageBounds, testRectCanvasBounds);

How to draw a rectangle on a WPF canvas

I'm trying to draw a Rectangle on a Canvas as follows:
System.Windows.Shapes.Rectangle rect;
rect = new System.Windows.Shapes.Rectangle();
rect.Stroke = new SolidColorBrush(Colors.Black);
rect.Fill = new SolidColorBrush(Colors.Black);
rect.Width=200;
rect.Height=200;
Canvas.SetLeft(rect,0);
Canvas.SetTop(rect,0);
front_canvas.Children.Add(rect);
Why would this code not draw a rectangle?
The canvas is defined in the associated XAML as follows:
<Canvas Height="200" Width="200" Name="front_canvas" Grid.Row="1" Grid.Column="0">
</Canvas>
The canvas shows up fine. I can tell because of the gap it leaves in the layout grid.

This should draw your rectangle as a 200x200 black square, provided front_canvas is displayed correctly.
Why would this code not draw a rectangle?
The main reasons this would not draw are:
front_canvas is not visible
front_canvas is not in the visual tree and being displayed correctly
Some other FrameworkElement is obscuring front_canvas, at least the upper left corner.
There is another object in the canvas at a higher z order.
Note that you'd typically also want to set StrokeThickness if you want to see the Stroke you specify.

To View Rectangle you must specify the StrokeThickness and set any Integer value greater than zero:
rect.StrokeThickness=2;

// ...
front_canvas.Children.Add(rect);
Size size = new Size(front_canvas.Width, front_canvas.Height);
front_canvas.Measure(size);
front_canvas.Arrange(new Rect(size));

Getting Camera to work well in Portrait mode

I added camera to an my App which is all in Portrait mode so would like the to keep it this way.
Here is the relevant code snippets I use in my .XAML
SupportedOrientations="Portrait" Orientation="Portrait"
mc:Ignorable="d" d:DesignHeight="800" d:DesignWidth="480"
<Canvas x:Name="viewfinderCanvas" Width="480" Height="800" >
<!--Camera viewfinder -->
<Canvas.Background>
<VideoBrush x:Name="viewfinderBrush">
</VideoBrush>
</Canvas.Background>
</Canvas>
Here is my setup code from the .XAML.CS
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
if (PhotoCamera.IsCameraTypeSupported(CameraType.FrontFacing))
{
cam = new Microsoft.Devices.PhotoCamera(CameraType.FrontFacing);
}
else
{
cam = new Microsoft.Devices.PhotoCamera(CameraType.Primary);
}
cam.Initialized += new EventHandler<Microsoft.Devices.CameraOperationCompletedEventArgs>(cam_Initialized);
cam.CaptureCompleted += new EventHandler<CameraOperationCompletedEventArgs>(cam_CaptureCompleted);
cam.CaptureImageAvailable += new EventHandler<Microsoft.Devices.ContentReadyEventArgs>(cam_CaptureImageAvailable);
cam.CaptureThumbnailAvailable += new EventHandler<ContentReadyEventArgs>(cam_CaptureThumbnailAvailable);
viewfinderBrush.SetSource(cam);
}
The problem is that I hold the phone in Portrait and point the phone at a person. The screen shows the persons head on the right side of the screen and the persons feet at the left of the screen.
While as they stand in front of me there head should be at the top of the screen and there feet at the bottm, cause these people aint superman.
So it seems the image from the camera is getting rotated -90 before it appears on the screen.
Can anybody explain whats going wrong and what sample code I need to implement to fix this problem.
Thanks,
-Code

You need to implement a VideoBrush.RelativeTransform, as detailed in the following article :-
http://msdn.microsoft.com/en-us/magazine/hh708750.aspx
Also covered in the following :-
ViewFinder Orientation With Windows Phone 7 Mango PhotoCamera

just add this line to the C# code of your camera page. It will transform and handle the camera video stream in portrait mode correctly.
viewfinderTransform.Rotation = 90;

Count the number of displayed VisualBrush visuals

I am working on a CAD program in WPF and I'm looking for a way to count the number of controls displayed when a particular brush is rendered.
So say I have an Ellipse:
<Ellipse x:Name="Ellipse" Canvas.Top="25" Canvas.Left="50" Width="400" Height="250" Stroke="DarkBlue" StrokeThickness="5" />
And I fill it with a VisualBrush from code behind:
VisualBrush tileCounter = new VisualBrush();
Rectangle rect = new Rectangle() { Width = 10, Height = 10, Fill = Brushes.Blue, Stroke = Brushes.BlueViolet, StrokeThickness = 1 };
tileCounter.Visual = rect;
tileCounter.TileMode = TileMode.Tile;
tileCounter.Stretch = Stretch.None;
tileCounter.Viewport = new Rect(0, 0, 10, 10);
tileCounter.ViewportUnits = BrushMappingMode.Absolute;
Ellipse.Fill = tileCounter;
Is there any way to get the VisualBrush to report back how many instances of the rectangle shape it has rendered as the fill of the Ellipse? Or are there code changes I could make to reference each visual individually from the parent using the Fill or Background?
I am currently working on a tool to draw figures that have any number of sides that are LineSegment, ArcSegment, or QuadraticBezierSegment and the brush is a grid that the user defines with entered hight, width, and grid size. The grid is also able to be realigned by the user. This makes simple mathematical solutions extremely hard to pull off and so a WPF solution would be preferable.
My ultimate goal is to get total number of visuals it attempts to render and then how much of each visual is rendered across the entire fill.

I'm sorry to tell you but I think you have to go the mathematical route.
Though I'm not entirely, sure I'd assume wpf is drawing that rect once and then caching the result, otherwise that visualbrush would not be performant. So essentially it really is only a texture, nothing where you could be aware of how many tiles have been drawn entirely or partially.