Rendering a Viewport3D with a RenderTargetBitmap.Render call seems to cause the Viewport3D to no longer update its visual content. The interactive actions still work though, such a hover-over and clicking.
I've created an example in which I have a viewport which contains a button. I then render the viewport with RenderTargetBitmap. After this render, I try to toggle the visibility of the button but the visuals of the button no longer update which is unexpected. It is however not possible to click on the button as you would expect when it is collapsed. Toggling back the visibility to visible allows me to click the button again so it seems that only the visuals are no longer processed correctly.
It seems that the viewport loses track of the correct buffer it should use and keeps displaying the old version no matter what. I would like the viewport to just keep updating its visuals as it did before the render call, any ideas what I am missing here?
I've uploaded the demonstrator on bitbucket, the sourcefiles can be viewed here:
Sourcecode
The demonstrator is also available as a VS2010 solution:
download solution
If you require any other information please let me know, I'll try to answer your questions as detailed as possible.
I was having a similar issue. After the call to RenderTargetBitmap's Render(), I noticed that, for example, any color changes applied to the visuals within the Viewport were not being displayed. As you state, the interactive actions like clicking, rotating, hover-over, etc. were still working.
Within my application the Viewport being rendered was itself sitting inside (i.e. a child of) a Grid. I found that if, after the call to RenderTargetBitmap's Render() method, I removed the Viewport from and then readded the Viewport to the Grid's 'Children' list, the visuals within the Viewport continued to update as they did before the call to Render().
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I'm trying to replicate Instagram's zoom feature on their list of videos on iOs using xamarin.forms.
I have a xamarin.forms ListView (actually a modified FlowListView) and I've been successful for the most part except for the fact that when I'm zooming, the zoomed view (an AVPlayerViewController) zooms fine but cannot extend beyond the size of the cell that contains it so it gets clipped. The effect is achieved by a simple UIPinchGestureRecognizer and UIPanGestureRecognizer and applying the appropriate Transform/Scale using CGAffineTransform.
You can see the problem here
From what I understand, the clipsToBounds property is what keeps views confined to their parent's frame so I tried:
setting clipsToBounds to false (even though that's supposed to be the default value) in the renderer and recursively to all the views' .Parent properties.
setting it to false in the default ViewCell renderer.
setting Xamarin's IsClippedToBounds to false at the xaml level.
Instagram also seems to blur the background of the zoomed video (as it is being zoomed) which would indicate that they've somehow moved the video view out of the cell and into some other temporary fullscreen view.
So I'm looking for some general guidance; is my understanding of clipsToBounds wrong? What is keeping the view from being drawn outside of its UITableViewCell? Should I approach this from a different angle? I'm at my wits' end, thanks in advance.
I'm working on a UWP app and I'm having some trouble with the visual states of some UI controls, specifically with buttons and toggle buttons.
Basically, I'd like the borders that become visible when you press the TAB key (to navigate using the keyboard) to have the same ZIndex of the rest of the control, ie. if part of the control is covered, they should be covered too in the same way. But, it looks like these borders are always displayed on top of the UI, no matter what. Here's a screen:
You can see the border going over the rest of the UI, while the rest of that toggle button is correctly covered. The same happens for buttons as well (not only toggle buttons), see here:
I've looked at the template for these controls, but I couldn't find anything related to these specific borders, nor to anything like an explicit Canvas.ZIndex setting or something like that.
I guess this behavior is on purpose, but is there a way to change this and make those borders behave like the rest of the UI?
Thanks!
EDIT: here you can see how a reveal highlight effect is correctly covered by the shadow and the other UI elements on the right, but the TAB border ignores that and is displayed on top of them.
I have noticed similar behavior was previously present in the Start menu as well (although it wasn't with focus border, but with the reveal effect clearly "continuing" into the cut-off portion of the button.
One workaround that comes to mind is to observe the state of the SplitView and when it is closed to actually change the width of the buttons (for example via a StateTrigger). This way the button's area will no longer be "hidden" and the focus border will work properly, as the buttons will end where they should.
When a form loads, I'd like it to show a loading image (within a Picture Box) and a standard Windows label with some text. However, all I see are white boxes, or sometimes I see another form underneath. How do I get the image and label to display properly.
I've tried setting AllowTransparency to false when the form loads, and also setting the Transparency Key of the form to some other colour, but nothing has worked.
The project is C# .Net v3.5 (also tried v4 and v4.5).
Any ideas?
First, you can't display an image, busy-wait, and then change the image - this will never redraw anything, leading to the symptoms you describe. To "wait" you will need to return control to your main application loop so it can continue to process messages (e.g. to handle redraw requests for your window). One way to do what you want is to display your initial state (splash screen) and then use a timer to call you back later to change the display to your second state.
The next problem you face is using forms controls with transparency. Most controls treat "transparent" as "fill your background with your parent controls color", which is not what you want. An easy way around this is to implement a Paint handler and draw the image and text for yourself - this gives you much more control of how your display looks, and will also allow you to get a cleaner redraw (no flicker or other problems caused by the display being built up but by bit in several controls)
Lastly, consider implementing your splash screen display as a separate control/form that you show above your main form during loading, as that makes it easy to "overlay" on your main form without having to change its design at all.
Just write formObjectName.Refresh() after formObjectName.Show()
I ran into a little problem while writing Windows 8 application on C#+xaml. My app has one main page, which is divided in two parts – ListView as a navigation panel on the left, and Frame on the right. All of that looks and works a bit like PC Settings panel. But there is one difference – when page into frame has enough content and it’s scrollable, I perform animation of collapsing navigation panel to icons-only state (when in full width it has text and icons).
So, here is the problem. Let’s say I’m on the first page and panel is collapsed. Then I go to the second page, and I've got to return to full-width state of panel. But since I’m doing it at the same time as showing content in the frame, there is a little freeze of animation, and it's becoming really noticeable when GridView has got a lot of items. So animation freezes on a half way, then GridView render all items images, and then it continue.
Only way to fix this problem I come up with, is to do navigation after animation completed. It’s doesn’t look very pretty, so I go on a blank page first, perform animation, and then go on target page. But this solution still feels wrong, and there still some problems with animation after resume from suspending.
So, is there any way to ensure that rendering of GridView will not interfere with my animation?
Thank you, and sorry for my English.
You can set NavigationCacheMode on the pages to Required and navigate through all the pages to preload them while hiding the Frame using the Opacity property, but that will be slow the first time you do it. Try to limit the number of bitmap pixels you need to decode and render on each page too. If all else fails - see if the Preload() method of the AlternativeFrame control from WinRT XAML Toolkit might be of help.
I have been trying to find out how to redraw a view when i have zoomed in on it, i have looked at many examples (mainly native code) but am still struggling to get it fully working.
So let me try and explain what i am attempting....
I have a UIScrollView With a UIView(container) in it this in turn has many views within it each with UITextFields inside, the functionality i am looking for is when a user clicks on any of the view it is zoomed in on and then goes back into place when the user is finished with it which does all actually work fine except for the quality of the zoomed in view is terrible.
I am using a UIScrollViewDelegate but not really sure what to put in the ZoomedEnded function to handle the redraw, I have tried using the CATiledLayer but am not really sure how this is used and i always just end up with a black screen.
There is not much code to show as
svCertScroller.SetZoomScale(2.34f, true);
Works fine and in the UIScrollDelegate event ViewForZoomingInScrollView just returns the view i want zoom in on but i don't have anything in ZoomingEnded event at the moment I have tried loads but nothing even seems to get close.
So any help on what to put inside this event to sharpen up the zoomed in view would be great.
Thanks in advance.
Make the scroll canvas larger and plot the contents at a higher resolution.