I need to capture the entire screen with a transparent WPF window as the topmost window.
I tried 2 approaches:
using System.Windows.Drawing.Graphics.CopyFromScreen
using WINAPI GetDesktopWindow
Both methods yield the same result. I get the entire screen EXCEPT my topmost transparent WPF window.
The WPF window w is created with:
w.AllowsTransparency = true;
w.WindowStyle = System.Windows.WindowStyle.None;
w.Background = new SolidColorBrush( Color.FromArgb( 1, 0, 0, 0 ) );
w.Topmost = true;
plus some content of course. The window covers the entire screen surface.
Apparently, the WPF window draws on a surface that is not included in GetDesktopWindow.
Can anybody pls shed some light on this and share some ideas how to truly get the entire screen surface?
Just found the solution:
As far as I can tell there is no solution for the Graphics.CopyFromScreen approach because you'd need to OR CopyPixelOperation.CaptureBlt with CopyPixelOperation.SourceCopy but you can't. The usual M$ inconsistency madness...
However, the WINAPI approach works since you can combine SRCCOPY and CAPTUREBLT when using BitBlt. Without CAPTUREBLT transparent and layered windows will not be included.
Related
I have a simple task that I want to accomplish: Have a WPF window launch with a Horizontal Alignment that is stretched to the total width of the current screen. I want to achieve a kind of custom Overlay MessageBox (I dont want to use third party controls such as MahApps), I am not using any third party references for this.
Please see what I have achieved so far (Not sure if the image will show, the link is http://imgur.com/e27DyNJ):
I have tried setting the width with a Controller object that I wrote which works, that basically sets the Width, Height, Left and Top to the width of the primary monitor. Downside is the window then pops up on the primary screen, not on the screen that is currently in use.
As far as I know, WPF doesn't have any multi-screen functions. You could PInvoke some native Multiple Display Monitor Functions, wrap them in a managed class and utilize them in that regard, though.
As a workaround, I have done the following:
var screen = System.Windows.Forms.Screen.FromRectangle(new System.Drawing.Rectangle((int)window.Left, (int)window.Top, (int)window.Width, (int)window.Height));
window.Width = screen.WorkingArea.Width;
window.Left = screen.WorkingArea.Left;
where window is the instance of my window I want to resize.
This works with the current screen the window was opened on.
I could begin by asking the question outright or by citing my sources (this, this, this, and this) descriptively, but I'll walk you ll through what I'm trying to do instead.
Let's start with a main window. It has its own window class whose hbrBackground is set to COLOR_BTNFACE + 1. Now let's do
EnableThemeDialogTexture(hwnd, ETDT_ENABLE | ETDT_USETABTEXTURE)
so the tab control we're about to add will be drawn with visual styles. (Try Windows XP with the standard Luna theme for best results.) Now let's add a tab control and two tabs.
On the first tab, we create an instance (let's call it container) of a new window class. This window class is going to hold various controls. I could set hbrBackground to COLOR_BTNFACE + 1, but then it will draw over the tab background. So I want this new child window to be transparent. So what I do is
set the class hbrBackground to GetStockObject(HOLLOW_BRUSH)
set container's extended style to WS_EX_TRANSPARENT
set the class WM_ERASEBKGND handler to do SetBkMode((HDC) wParam, TRANSPARENT); return 0; to set the device context and have Windows draw the transparent background.
So far so good, right? I'm not sure if I'm really doing all this correctly, and I'd like this to also be flicker-free, which doesn't seem to happen: when I resize the window (at least in wine) I get either flicker or garbage drawn (even in child controls, somehow!). Windows XP in a VM just shows flicker. I tried tweaking some settings but to no avail.
But wait, now I want to have another control, one that just draws some bitmap data. On the next tab, create another container, then have a third window class area as a child of that. area only draws in the upper-left 100x100 area and has scrollbars; the rest of the window area should be transparent.
Right now, what I have for area is:
the window class hbrBackground set to NULL and styles CS_HREDRAW and CS_VREDRAW set
the extended window style being 0
the WM_ERASEBKGND simply doing return 1;
the WM_PAINT filling the entire update rect with COLOR_BTNFACE + 1 before drawing, and rendering all of it
This is flicker-free, but obviously not transparent. NOW I'm really not sure what to do, because I want the area to be transparent in such a way that it shows the tab control background. Again, I tried tweaking settings to bring them closer to what I tried above with container, but I got either flicker or invalidation leftovers when I tried.
So how do I get both of these custom control types (the container and the drawing area) to be both flicker-free and transparent?
I presently must target Windows XP at a minimum, though if the solution would be easier with Vista+ only I'd be happy to keep that solution on the side in case I ever drop XP support (unfortunately Stack Overflow doesn't let me hand out silver medals...).
Thanks!
To paint your window in a manner that is "flicker free", you will need to paint your window to a bitmap, then copy the bitmap to the destination device context. On Windows XP, you will need to create a bitmap, adjust the origin of the drawing DC and then paint your window. On Vista and later you can use BeginBufferedPaint and its associated routines to do the buffering for you.
Once you have buffered painting working, you can then use WM_PRINTCLIENT to paint your window's parent window into the your drawing DC before you do any actual drawing. Unfortunately, not all windows will support WM_PRINTCLIENT.
You could consider using DrawThemeParentBackground, rather than WM_PRINTCLIENT directly.
Combining these two methods together will leave you with transparent flicker-free drawing.
I have WPF window in which my Direct3D engine render. WPF Window I start from my engine, which I develop on C++/CLI.
I have 2 displays and when I move window between them, part of the window became white and not update until I am not stop dragging it (like on screen shot).
Does somebody know how to fix this issue?
It will be hard to post code here as it is a lot of code, but I will try:
I use managed C++ and unmanaged in one project:
So, I add .Net dll`s to have access to the WPF window:
Window^ wnd = gcnew Window();
wnd->Width = 1280;
wnd->Height = 720;
wnd->Show();
WindowInteropHelper^ helper = gcnew WindowInteropHelper(wnd);
HWND WPFHwnd = (HWND)helper->Handle.ToPointer();
HINSTANCE hinstance = (HINSTANCE)Marshal::GetHINSTANCE(this->GetType()->Module).ToPointer();
engine->SetHisnstanceHWND(WPFHwnd, hinstance);
engine->InitializeSystem(wnd->ActualWidth, wnd->ActualHeight);
engine - this is unmanaged class which incapsulates all work with rendering.
Further it is a stardard d3d rendering loop. Nothing special.
It render OK, but when I resizing or move window, it draw a part of it like this (with white). When I stop resizing or moving - all OK again.
My question is: is it possible to get rid of this effect or not?
UPDATE:
I hooked the wndProc if the WPF window and try to use UpdateLayout() when size changing, but this has no effect. Seems window is not react on any intervention.
Well, it sounds like your engine is receiving WM_ERASEBKGND and it clears the window. After you release the window, it sends WM_PAINT and everything is clear again. That's what I believe might be happening.
In order to test this theory, you can handle that message and return true. Put that to your engine message handling routine:
case WM_ERASEBKGND:
{
PAINTSTRUCT pss;
BeginPaint(hWnd,&pss);
EndPaint(hWnd,&pss);
return true;
}
You can use WinSpy++ to check out what messages are delivered to underneath window. If you want to see why the background is whited out, you can do it through ProcessMonitor and see what API calls are being issued. You're probably interested in API calls that include the color white.
I have a panel and on that I've a picturebox. There are around 20 labels that I've to show in the panel. I want the background of Label to be transparent ie the image in picturebox is shown and the label displays only the text.
Now since labels do not exhibit true transparency I made the labels child of picturebox
this.lbl1.Parent = pictureBox1;
This has solved my immediate problem but now when the form loads, all the labels take a while to become visible and do so one at a time. I'd appreciate if you guys can give some solution for this.
Thanks in advance
The standard cure for flicker is double-buffering. But that cannot solve this kind of flicker. It is a different kind, caused by having multiple windows overlapping each other. Each label is its own window. When the form needs to paint itself, it draws its background leaving holes for the child windows. Each child window then takes a turn drawing itself. And their child windows draw themselves next. Etcetera.
This becomes noticeable when one control takes a while to draw, no doubt your picture box. Especially when it displays a large image that needs to be resized. The holes for the child windows stay unpainted while the picture box draws. They have a white background, black when you use the form's TransparencyKey or Opacity property. This can contrast badly with the image in your picture box, that effect is perceived by the user as flicker.
One immediate cure is to not use controls so you don't pay for their window. A Label is very convenient but it is a massive waste of system resources to burn up a window just to display a string. You can simply implement the picture box' Paint event and draw the strings with TextRenderer.DrawText(). PictureBox has double-buffering turned on by default so the image as well as the text is drawn completely smoothly, no more flicker. The obvious disadvantage is that you lose the convenience of point-and-click, you have to write code.
There are other fixes possible. One of them is to prevent the picture box from leaving holes for the child windows. It will draw the entire image, the labels pop on top of them. That's still flicker but not nearly as noticeable. Add a new class to your project and paste this code:
using System;
using System.Windows.Forms;
internal class MyPictureBox : PictureBox {
protected override CreateParams CreateParams {
get {
var parms = base.CreateParams;
parms.Style &= ~0x02000000; // Turn off WS_CLIPCHILDREN
return parms;
}
}
}
Compile and drop the new picture box control from the top of the toolbox onto your form.
Yet another possible workaround is to make the form and all of its children double-buffered. This doesn't speed up the painting at all but all of the windows get rendered into a memory buffer, the result is blitted to the screen. You'll notice a delay but the window suddenly pops on the screen. This is called compositing. Winforms doesn't support this directly since it can have side-effects but it is easy to enable. Paste this code into your form class:
protected override CreateParams CreateParams {
get {
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x02000000; // Turn on WS_EX_COMPOSITED
return cp;
}
}
Supported by XP and later. Watch out for painting artifacts.
or you can ditch the labels and draw the text yourself:
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
TextRenderer.DrawText(e.Graphics, "Label1", SystemFonts.DefaultFont,
new Point(10, 10), Color.Black, Color.Empty);
}
The label does not support transparency, you must create your own unique custom control, you can see these code examples.
http://www.codeproject.com/KB/dotnet/transparent_controls_net.aspx http://www.codeproject.com/KB/vb/uLabelX.aspx
Bye
We use Windows Forms and custom user controls, and I would like to be able to rotate the panel hosting the userControl in a particular form. I have seen similar functionnalities with WPF, but I can't use it for the moment. Is it possible to achieve the rotation of a panel and its children using possibly built-in .NET methods or GDI+?
I have seen some pretty cool visual effect with menus that are displayed in game development, so I was wondering if it would be possible to create similar effects using Windows Forms.
Rotating a panel and its children in Windows Forms is not something directly supported, and I think it will end up being a buggy headache that could easily suck up lots of time. It's especially painful to think about when you could do this in WPF with zero lines of C# code and only a tiny bit of XAML.
You can use rotations in GDI+ by calling the RotateTransform method on a Graphics object.
However, rotating an entire control is not so simple, and will depend heavily on how the control is implemented.
If it's a composite UserControl that has other controls inside of it, you're out of luck.
If it's a sinlge control that paints itself, try inheriting the control, overriding the OnPaint method, and calling RotateTransform on the Graphics object. However, you will probably have trouble with it. In particular, you will probably need to override all of the mouse events and call the base control's events with rotated coordinates.
You can get halfway there by calling the DrawToBitmap method on your panel, then rotating the bitmap and displaying it e.g. in a PictureBox:
var bitmap = new Bitmap(panel.Width, panel.Height);
panel.DrawToBitmap(bitmap, new Rectangle(Point.Empty, panel.Size));
bitmap.RotateFlip(RotateFlipType.Rotate270FlipNone);
var pictureBox = new PictureBox();
pictureBox.Location = panel.Location;
pictureBox.SizeMode = PictureBoxSizeMode.AutoSize;
pictureBox.Image = bitmap;
Controls.Remove(panel);
Controls.Add(pictureBox);
Rotation angles other than 90-degree increments are also possible, if you draw the bitmap into another bitmap using GDI:
var bitmap2 = new Bitmap(bmp.Width + 75, bmp.Height + 100);
var graphics = Graphics.FromImage(bmp2);
graphics.TranslateTransform(bitmap2.Width / 2, bitmap2.Height / 2);
graphics.RotateTransform(-15f);
graphics.TranslateTransform(-bitmap.Width / 2, -bitmap.Height / 2);
graphics.DrawImageUnscaled(bitmap, Point.Empty);
graphics.Dispose();
The problem of course is that you're only displaying an image of your panel, and not the panel itself, so it's no longer possible to interact with the controls inside.
That could probably be done as well, but you would have to mess with window messages, which gets quite a bit more complicated. Depending on your needs you might also be able to get away with handling click and key events on the PictureBox, manipulating the controls in the panel, and then updating the image.