Develop Reference

Get default TitleBar height programmatically before a titlebar is created?

I am creating a custom title bar for my uwp app. I want to match the height of the system bar.
I might be able to get that height be calling
CoreApplication.GetCurrentView().TitleBar.Height
But that depends on a lot of things. The title bar may not have been sized yet.
I've also seen a suggestion (from winforms) to look at the difference of the y coordinates of the window top and the content view top. But again that seems fishy. For one thing, once I've set ExtendViewIntoTitleBar to true, I don't think the method would work.
Is there reliable way to programmatically get the default height?

I know that this answer might not be useful to the person who initially asked, at this point of time, but I would still like to suggest the answer:
You can register a handler for when the size of title bar changes. (The docs mention size change, but it may only be the caption button offset and not height)
This piece of code works well for me, at least at the moment
//Put the below line in the Page initialization/OnNavigated function
var coreTitleBar = CoreApplication.GetCurrentView().TitleBar;
coreTitleBar.ExtendViewIntoTitleBar = true;
coreTitleBar.LayoutMetricsChanged += CoreTitleBar_LayoutMetricsChanged;
private void CoreTitleBar_LayoutMetricsChanged(CoreApplicationViewTitleBar sender, object args)
{
MyAppTitleBar.Height = sender.Height;
}
The above code calls your function (CoreTitleBar_LayoutMetricsChanged) automatically whenever the dimensions of the titleBar change (like change in DPI). Here, MyAppTitleBar is a Grid I made for my custom title bar.
Futher info can be found here

WinForms scrollable control touch behavior

I have a SplitContainer which contains Atalasoft's AnnotateViewer. Class hierarchy is as follows:
System.Windows.Forms.Control
Atalasoft.Imaging.WinControls.ScrollPort
...
Atalasoft.Annotate.UI.AnnotateViewer
My.AnnotateViewer
Now the problem: As long as the content of the SplitContainer is smaller than the actual viewport, hence no scrollbars visible, touch input is interpreted as left mouse down, mouse move and left mouse up which is exactly what I'd expect and love to see. I could still use two-finger-panning to scroll the view. BUT: If I zoom the viewer, so that my content gets larger than my viewport, scrollbars appear and touch input behaves differently: Horizontal panning stays the same, but vertical panning now causes scrolling, even with a single finger.
The question is: Is this behavior Atalasoft-specific, WinForms-specific or system-specific and can I do something to change it? I'd like a single finger to always convert to left click and move. Two finger's for scrolling is fine (and already works.)
I fear that it is system specific because you can find the exact same behavior in Word 2010. Still, it's a Microsoft product.

I begin to hate the fact that you so often get sudden inspiration after finally typing down your problem to a forum or similar.
This problem was now solved by re-registering for gesture events. You are able to register for all pan gestures except for horizontal and/or vertical single finger pan.
// adapt the gesture registration for this window
GESTURECONFIG[] gestureConfig = new[]
{
// register for zoom gesture
new GESTURECONFIG { dwID = GID_ZOOM, dwWant = GC_ZOOM, dwBlock = 0 },
// register for pan gestures but ignore single finger (only use two-finger-pan to scroll)
new GESTURECONFIG { dwID = GID_PAN, dwWant = GC_PAN, dwBlock = GC_PAN_WITH_SINGLE_FINGER_HORIZONTALLY | GC_PAN_WITH_SINGLE_FINGER_VERTICALLY }
};
SetGestureConfig(this.Handle, 0, (uint)gestureConfig.Length, gestureConfig, (uint)Marshal.SizeOf(typeof(GESTURECONFIG)));
Details here:
http://msdn.microsoft.com/de-de/library/dd353241%28v=vs.85%29.aspx
I think this is the cleanest solution you can get.

The SetGestureConfig API accepts an GESTURECONFIG struct as its 4th parameter. How can you pass in a GESTURECONFIG[] array?

Windows Phone Navigation transitions delay and blank screen in between

I'm using WP Toolkit to do the transitions between my app pages, it works fine , but I get this strange delay in between transitions while navigating from one page to another, it just shows a blank screen which obviously doesn't look good, without any transition it opens the page straight away without any delay or blank screen. This has taken almost 2 days of my time and I don't know what's wrong, I'd appreciate it if someone can help me with it or suggest another page transition library .
(I tried WP7Contrib transitions but I have the same problem with that, not sure if its my app or the libraries)

In fact the background between transitions is black and to avoid that kind of behavior I solved the issue by setting the background in the App.Xaml.cs
private void InitializePhoneApplication()
{
if (phoneApplicationInitialized)
return;
// Create the frame but don't set it as RootVisual yet; this allows the splash
// screen to remain active until the application is ready to render.
RootFrame = new TransitionFrame();
var brush = new ImageBrush
{
ImageSource = new System.Windows.Media.Imaging.BitmapImage(new Uri("Images/Background.jpg", UriKind.Relative)),
Opacity = 0.8d
};
RootFrame.Background = brush;
RootFrame.Navigated += CompleteInitializePhoneApplication;
// Handle navigation failures
RootFrame.NavigationFailed += RootFrame_NavigationFailed;
// Ensure we don't initialize again
phoneApplicationInitialized = true;
}
With that all my pages have my background and the black background is no longer displayed during the transition.

I would suggest you to create your own slide transitions between pages. Its quite simple actually. Create a storyboard and play them at onNavigatingFrom and onNavigatedTo functions in both the page you are navigating from and page you are going into respectively. It just gives me what and how i wanted in my applications. Removing additional references makes your code more optimized.

C# Drag and Drop Effect with Overlay/Opaque Image

I think this would be simple question and should be asked in the pas few years but unable to google around and dont know if there is a specific keyword.
In c# WinForm I want to do drag and drop but I dont want the image of DragDropEffects Move, Copy or whatever. I want to display an image with half opaque. Just like Firefox when dragging an image, you would see the image folowing the mouse pointer like a ghost :)
I already Implement DoDragDrop, DragEnter and DragDrop events. I just want to customize the dragging effects with overlay image.

Might be 9 years too late to the party 😄
I always liked Drag&Drop interactions but found it complicated to use in WinForms. Especially if you want it to look professional with overlays.
I made my own library for WinForms the last time I needed Drag&Drop. You can find it here or on NuGet:
https://github.com/awaescher/FluentDragDrop
Here's everything you need to implement Drag&Drop like shown above:
private void picControlPreviewBehindCursor_MouseDown(object sender, MouseEventArgs e)
{
var pic = (PictureBox)sender;
pic.InitializeDragAndDrop()
.Copy()
.Immediately()
.WithData(pic.Image)
.WithPreview().BehindCursor()
.To(PreviewBoxes, (target, data) => target.Image = data);
// Copy(), Move() or Link() to define allowed effects
// Immediately() or OnMouseMove() for deferred start on mouse move
// WithData() to pass any object you like
// WithPreview() to define your preview and how it should behave
// BehindCursor() or RelativeToCursor() to define the preview placement
// To() to define target controls and how the dragged data should be used on drop
}

How to draw on an unfilled box on a video stream using the mouse

I am using dshownet(first time) and C#. I have got a sample to take the web cam input and display it on a form. I now need to draw a rectangle on top of the video stream using the mouse. (the intent is to track what is inside the box from there onwards).
I heard that there is something called VMR. So I went to the dshownet samples and went through them. I didnt find any samples that use the mouse to overlay a shape on the video stream. Someone on here suggested to use colorkey. Another person said to use GDI+ and mouse handling. I tried to compile the DXLogo sample but got this error :
Error 1 Cannot create an instance of the abstract class or interface 'System.Drawing.Image' C:\Documents and Settings\TLNA\Desktop\Final Year Project\Libraries\DirectShow library 2\DirectShowSamples-2010-February\Samples\Capture\DxLogo\Capture.cs 128 32 DxLogo-2008
for the code section:
if (fileName.Length > 0)
{
m_Bitmap = new Image(fileName); // error happened here
Rectangle r = new Rectangle(0, 0, m_Bitmap.Width, m_Bitmap.Height);
m_bmdLogo = m_Bitmap.LockBits(r, ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
}
I know that I must go through the Bitmap9 Interface. But I really dont know where to start. Should I read the Directshow API docs.
btw I also have the book Programming Microsoft Directshow for digital video and television. I started reading that book and stopped after a few pages since the code is mainly in C++. Should I continue to read this is book ? How can I accomplish the certain mentioned tasks in C# ?
Any suggestions as how to draw on the video. Some useful links(tutorials) would be helpful.
Many Thanks
Tlna

I'm not sure why the DirectShow sample doesn't compile, but you may be able to change the problem line:
m_Bitmap = new Image(fileName);
to this:
m_Bitmap = new Bitmap(fileName);
and get it to work.
You're actually facing a pretty difficult problem here. DirectShow renders a video by drawing a series of still frames to a device context (like a PictureBox or a Form, or even the screen) many times a second (depending on whatever the frame rate is). You (as a programmer) can also (easily) render graphics directly to this same device context.
However, in order to make your drawn box appear over top of a running video, your code needs to draw the rectangle immediately after DirectShow draws each frame of the video; otherwise, the next frame will obliterate your rectangle. DirectShow objects probably have some sort of frame rendering event that you can handle, and then inside the event handler you just re-draw your box (based on the initial and current mouse coordinates, which you can get from the MouseDown and MouseMove events of whatever control you're drawing on).
Update: I just took a look at my code from when I was playing around with DirectShow.NET, and it looks like there is an event (DsEvCode.Repaint) that you could hook into and use to draw your box.
I haven't looked at the code sample you're working with, but do a search and see if you can find an OnGraphNotify() method in your code, you should be able to add something like this:
if (code == DsEvCode.Repaint)
{
// draw the box here
}
Presumably, this event is fired after each frame of the video is rendered, so if you redraw your box here every time it will appear as if the box is persisting.