I have a Windows Store app with a ScrollViewer and an Image in it. When i double tap on the ScrollViewer I want it to zoom the Image to its width. This part is not a problem but I also want the Image to be centered after it has beed zoomed in.
I tried calling the ScrollToHorizontalOffset method on the ScrollViewer but It does not seem to work with any number I give it. What is the problem?
Perhaps the offset only works for the non-zoomed view where your image fills the ScrollViewer completely and thus can't be scrolled. You could try setting the image dimensions so that it is larger than the ScrollViewer, but set original ZoomFactor, so that it fills the ScrollViewer at first. Then zooming and scrolling might work.
Assign a SizeChangedEvent in the scrollviewer.
<ScrollViewer SizeChanged="OnSizeChange"></ScrollViewer>
like this. Then it is better to place your image inside a canvas. So your code will be probably like this.
<ScrollViewer SizeChanged="OnSizeChange" x:Name="scrl">
<Canvas RenderTransformOrigin="0.5,0.5" x:Name="main">
<Image source="" Canvas.Top="insert desire double value here", Canvas.Left="Same goes here"/>
</Canvas>
</ScrollViewer>
then in the code behind you can change the height and width of your canvass depending on the scroll viewer
Main.Width = scrl.ViewPortWidth;
Main.Height = scrl.ViewPortHeight;
You can experiment on the size of the canvass while adding a double tap event to it. Changing the size of the canvas can zoom in or out the image because the image is inside the canvass
Try with 'ChangeView' instead of 'ZoomToFactor'
Related
Hi I'm hoping someone can help point me in the right direction to how i might go about solving this issue.
I have a blank image (white) which is 3000x1500 which acts a a canvas, i then have an image which again could be any size and any orientation. What i need to do is scale this image to fit inside the blank white canvas as best as possible and also center it. I would expect to see white gaps at the top or bottom of the final image if the image could not be scaled to fix the exact canvas.
Can anyone suggest what i should research, how i would go about drawing an image inside another in C# WPF and anything that may already exist that i could use to achieve this.
I forgot to mention that this would need to output to a bitmap so it could be saved to disk
All you need to do is to put an Image control into an appropriately sized Grid with white background, and set its Stretch property to Uniform. No Viewbox required.
<Grid Width="3000" Height="1500" Background="White">
<Image Source="<path to image file>" Stretch="Uniform"/>
</Grid>
Look up ViewBox. A ViewBox automatically scales its single child element based off of the stretch parameter.
I have a simple scrollviewer setup in my wpf application. Everything works fine, Now I want my scrollviewer's content should use the space of my the scollbar as well, As my scrollbar is transparent it could easily display the content.
Just like the scrollbars in facebook. Attached is the image of the output. Green Section is the content and red section is scollviewer's area.
I am using WrapPanel in my scrollviewer, this is the code snippet
<ScrollViewer x:Name="ScrollViewer1"
HorizontalScrollBarVisibility="Auto"
VerticalScrollBarVisibility="Hidden">
<WrapPanel x:Name="WrapPanel1" SizeChanged="WrapPanel1_SizeChanged" />
</ScrollViewer>
You have to edit the ScrollViewer's ControlTemplate which should look like the one in this page : http://msdn.microsoft.com/en-us/library/aa970847(v=vs.110).aspx
In the ScrollViewer Control Template Example, you can see that the ScrollContentPresenter is inside a Border which is inside the first row of a 2-rows Grid.
Setting the RowSpan to 2 for this Border would achieve the effect you want.
I have a Windows Store app with a Hub page. On one HubSection i show a Image.
The Image should be Zoomable so i add a ScrollViewer and set ZoomMode to Enabled.
But now the Image is not scaled to the height of the Hub anymore. (It uses the size of the Bitmap)
If i remove the ScrollViewer the Image is scaled to the current Height and keeps the Height/Width ratio.
<ScrollViewer ZoomMode="Enabled" VerticalScrollBarVisibility="Auto"
HorizontalScrollBarVisibility="Auto">
<Image Source="{Binding Image1}" />
</ScrollViewer>
How can i get the ScrollViewer to Fill my Parent? (VerticalAlignment does not work)
Try putting VerticalScrollBarVisibility to Disabled, in that way the image height has to fit the height of the hub control.
(Can't add pictures so I'll try and explain it) So my program basically consists of two parts: a bitmap image that is scanned and shown in the main window (on a canvas), and a canvas derived class I made that basically takes data (b&w values ranging from 0-255) from the image and represents it in a histogram format (a bargraph basically) and it overlays the bitmap image (its transparent so you can still see the image).
Alright so I got my program working, the only problem is my canvas derived class wont stretch until I "refresh" the screen. The children of the class (being windows shapes rectangles) wont stretch with the window.
It looks fine up to this point
but then I maximize it...
The rectangles then just stay exactly where they're at. It isn't until I click the "display histogram" button that it will disappear and then after clicking it again, I get...
...Exactly what I want, the histogram is in the right place on the screen. So here's my question, how can I get the histogram to stretch with the main window? instead of having to refresh it every time?
<Border Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="3" BorderBrush="Black" BorderThickness="5" x:Name="testview">
<local:DrawingCanvas x:Name="pbHistogram" IsHitTestVisible="False"
Width="Auto"
Background="Transparent"
Height ="{Binding Path=ActualHeight, ElementName=testview}"/>
</Border>
I know this is not really an answer, but I think the problem is the canvas class itself. It has no automatic layouting or resizing of its child elements. Link to msdn: http://msdn.microsoft.com/en-us/library/ms609101(v=vs.100).aspx
What you could try is to hook up to your main window's resize event and call the same function that the buttonpress calls.
Maybe the quickest, easiest way to do this would be to put your canvas in a Viewbox.
I'm writing a WPF app that has a Canvas in it. This canvas will be custom rendered at runtime. It's sort of like a game in that it needs to be measured in pixels. I need to be able to set my Canvas to 478x478 pixels (client rectangle size). I don't want any scaling or other resolution-independent steps to take place on my Canvas.
I'm not sure if this is possible in WPF, since its nature is to be resolution independent. My questions:
How do I resize my Canvas at runtime (function to call?)
When I resize my Canvas, is the renderable area (the client rectangle) going to be that size? If not, how can I resize it to make sure the client rectangle is a specific width/height?
Is it possible to set the width/height of the Canvas in Pixels? How does the resolution-independent aspect of WPF interfere with what I'm trying to do?
When I resize my Canvas, will other controls resize appropriately as they have been designed to do in the WPF designer?
Thanks in advance.
Any elements positioned in a canvas will not resize or reposition based upon the size of the canvas. So I don't think there's any advantage to setting the size of the canvas. Maybe you should just set a fixed size of the window instead.
Otherwise, just set the Canvas.Width, Height, and ClipToBounds=True and you have a fixed sized canvas that positions its child elements with X/Y coordinates.
Also you should be sure to set SnapsToDevicePixels=True on the canvas so that child elements will have crisp pixel-aligned bounds.
resizing is cake:
MyCanvas.Width = 350;
MyCanvas.Height = 450;
this sets the size, you CAN render to coordinates outside of this, but it will be clipped. You can wrap your canvas inside a scroller to allow the user to see what is outside the height/width of the canvas.
as for the rest of your questions, i think you can see this SO question for your answers
Update 2020: on WPF .NET CORE: If the Canvas is a child of a Viewbox, the content is automatically scaled to the Viewbox height and width.
<Viewbox Stretch="Fill"
Width="50"
Height="50">
<Canvas>
<Path.... />
</Canvas>
</Viewbox>