Windows API - Maximize a window across all monitors - winapi

We have a custom RDP client that we've built using the RDP ActiveX control and MFC:
https://learn.microsoft.com/en-us/windows/win32/termserv/using-remote-desktop-web-connection
In order to support multiple monitors, we use the put_UseMultimon function:
https://learn.microsoft.com/en-us/windows/win32/termserv/imsrdpclientnonscriptable5-usemultimon
This kind of works, but we have to manually stretch the window across the monitors. Maximizing the window will maximize it on one of the monitors. The experience we get is not so good, we can't really use the entire area, and the window title bar remains (when maximizing the window on one screen it disappears).
We would like to get an experience similar to mstsc, where maximizing the window will change it's style to maximized and make the window span on the entire area. Is there a way to maximize a window and make it span across all monitors?

#JonathanPotter is right.
WM_GETMINMAXINFO sent to a window when the size or position of the
window is about to change. An application can use this message to
override the window's default maximized size and position.
The following is an example to achieve this purpose. (Note: Extend from main display to the second display does work. otherwise doesn't work.)
case WM_GETMINMAXINFO:
MINMAXINFO* maxInfo = (MINMAXINFO*)lParam;
maxInfo->ptMaxPosition.x = GetSystemMetrics(SM_XVIRTUALSCREEN);
maxInfo->ptMaxPosition.y = GetSystemMetrics(SM_YVIRTUALSCREEN);
maxInfo->ptMaxSize.x = GetSystemMetrics(SM_CXVIRTUALSCREEN);
maxInfo->ptMaxSize.y = GetSystemMetrics(SM_CYVIRTUALSCREEN);
return 0;
More reference: "Multiple Monitor System Metrics" "GetSystemMetrics function".

Related

Win32: How to make popup window match monitor DPI

I'm working on a Win32 app with multiple windows, some of which use WS_POPUPWINDOW style (no caption) and some of which use WS_OVERLAPPEDWINDOW style. The app has System DPI awareness.
When I move the overlapped windows between monitors, they scale to match the current monitor DPI as expected. But the popup windows only do this if there are no other open overlapped windows. Otherwise, they always try to match the scaling of the last active overlapped window in the same process, even if it's on another monitor with a different scale factor.
I guess this makes sense for some use cases, since you'd always want eg. a popup menu to match the scale of the current window. But I want my popups to behave as independent windows with their own scale factor.
How do I make popup windows always match the DPI of the monitor that they're positioned on?
As a quick fix before I eventually convert the app to per-monitor DPI awareness, I created an invisible overlapped owner window for the popup that tracks its position / size. This ensures that whenever the popup is active, it updates to use its owner's scaling, which always matches the current monitor.

DirectX11 Swapchain and window losing fullscreen status

I just stumbled on this little annoying behavior, while adding full screen support on a sample program.
Creating a full screen window works, but as soon as I move any window (from another application) on the output that contains my fullscreen window, it automatically switches back to windowed.
Is there any way to prevent this behavior (so full screen window do not go back to windowed)?
As a reference, this is a small standalone example (so problem can be replicated easily).
Also if that is useful, I'm running on Windows 8.1.
I already tried to change WindowAssociationFlags and SwapChainFlags, both with no success, same as using FlipSequential instead of Discard
SharpDX.DXGI.Factory2 factory = new SharpDX.DXGI.Factory2();
SharpDX.DXGI.Adapter adapter = factory.GetAdapter(0);
var renderForm1 = new RenderForm("Form 1");
factory.MakeWindowAssociation(renderForm1.Handle, SharpDX.DXGI.WindowAssociationFlags.IgnoreAll);
Device device = new Device(adapter, DeviceCreationFlags.BgraSupport);
SharpDX.DXGI.SwapChainDescription sd = new SharpDX.DXGI.SwapChainDescription()
{
BufferCount = 2,
ModeDescription = new SharpDX.DXGI.ModeDescription(0, 0, new SharpDX.DXGI.Rational(50, 1), SharpDX.DXGI.Format.R8G8B8A8_UNorm),
IsWindowed = true,
OutputHandle = renderForm1.Handle,
SampleDescription = new SharpDX.DXGI.SampleDescription(1,0),
SwapEffect = SharpDX.DXGI.SwapEffect.Discard,
Usage = SharpDX.DXGI.Usage.RenderTargetOutput,
Flags = SharpDX.DXGI.SwapChainFlags.None
};
var swapChain1 = new SharpDX.DXGI.SwapChain(factory, device, sd);
renderForm1.Left = 1922; //Just hardcoded here to move window to second screen
renderForm1.Width = 1920;
renderForm1.Height = 1080;
renderForm1.FormBorderStyle = FormBorderStyle.None;
swapChain1.SetFullscreenState(true, null);
swapChain1.ResizeBuffers(2, 1920, 1080, SharpDX.DXGI.Format.R8G8B8A8_UNorm, SharpDX.DXGI.SwapChainFlags.AllowModeSwitch);
var resource = Texture2D.FromSwapChain<Texture2D>(swapChain1, 0);
var renderView = new RenderTargetView(device, resource);
RenderLoop.Run(renderForm1, () =>
{
device.ImmediateContext.ClearRenderTargetView(renderView, new SharpDX.Color4(1, 0, 0, 1));
swapChain1.Present(1, SharpDX.DXGI.PresentFlags.None);
});
Edit:
I also tried a c++ sample (just taken DirectX11 basic tutorial from Microsoft and added full screen switch), this leads to the same behavior, so this is not a SharpDX specific issue.
I looked at the message loop, and once this occurs, first fullscreen mode is changed back to windowed, and I receive a WM_DISPLAYCHANGE message).
This sounds like expected behavior. If you have a full screen 'exclusive' mode swapchain and the associated window loses focus, the system automatically switches the application out of full screen mode back to windowed mode by design.
With a single monitor, it mostly works as long as you have your applications' window sized to fill the display. Users can't use the mouse to change focus of your window, and it requires something like ALT+TAB to switch focus.
With multiple monitors, it's a real problem. If you click on another window on another display, your app loses focus and the full screen mode is again switched out. There are also limitations that prevent you from setting full screen 'exclusive' mode on more than one monitor.
Furthermore, on Windows Vista or later the notion of 'exclusive' mode is an illusion: the GPU is always shared anyhow. The 'focus' application gets priority whether it is a full screen or a windowed swap chain.
For a Windows desktop apps you have three choices for a full screen style experience:
Use the traditional full screen 'exclusive' mode with a window sized to fill the display, along with setting the display mode which may not be what the user has set for Windows generally. Here you have IsWindowed = false.
You set the window size to fill the full display (i.e. maximized). You can use windows styles to ensure that the window has no frame which results in a full screen style experience (WS_POPUP). Here you have IsWindowed = true, and you should be sure to set DXGI_MWA_NO_ALT_ENTER to avoid allowing DXGI to try to take you to use the 1 case.
You can do the same as 2 with IsWindowed = true and the borderless window sized to match the screen, but you change the display mode to something other than the system default. This is commonly referred to as 'fake full screen'. The display mode gets changed back whenever you exit the application.
1 has all has all the problems with multi-tasking and focus we just described. 2 and 3 allow system notifications and other pop-ups to show up over the game and not force a mode switch. 2 and 3 also work a lot better in multi-monitor setups where you can play your game on one display and use other apps on another display. For multi-tasking most people to prefer a classic window style with a frame border.
Windows Store UWP notions of full screen mode is basically like 2 above. You can't change the display mode with a UWP.
Debugging a full-screen setup is quite challenging. With multiple monitors, 2 and 3 can work with your debugger on the other screen. For true full-screen exclusive mode, really the only option is to use remote debugging from another PC.
Another issue with 1 and 3 is that you can set the display mode to something that won't sync with the display leaving the user with a system with no UI and no way to exit. Ideally with the right driver setup, the DXGI enumeration list does not contain unsupported modes, but it is something to be aware of. For this reason, your UI for selecting a display mode should have a timeout and you should make sure there's a reasonable way to abort the application with the keyboard if the display mode fails to sync at some point in the future. Using the existing display mode as we do in 2 above is always the safest option.
The main reason to use full screen exclusive mode (1) above is to try to get 'flip' rather than 'blit' of the backbuffer/frontbuffer. For most modern systems, this is a negligible performance difference. The other reason to go through the pain of using it is for SLI/Crossfire multi-GPU rendering going to a single display. There are a number of other optimizations required to really make that scenario work, and it's pretty niche. You should seek out the vendor optimization guides for the details.
Most modern games default to using fake full screen rather than full screen 'exclusive' mode. They offer the ability to use a true windowed mode as many users want to be able to multi-task while playing (like looking up hints online, use IM or external voice chat, etc.). AAA Windows desktop games that want to support tuned high-performance gaming for SLI/Crossfire will offer a full screen 'exclusive' mode, but this requires some work to get working fully and entails more work than just some DXGI code.
See DXGI Overview and DirectX Graphics Infrastructure (DXGI): Best Practices
After several attempts and trials, here are the different workarounds I used, none are ideal but all are somehow better than getting a mode change.
1/Force cursor in the middle of the full screen window, with a keyboard shortcut to get control again.
This is not ideal since we can't really do anything while our part is running, but at least prevents accidental "disaster click". It does not prevent keyboard interaction either.
2/Use a DX9 renderer with a shared texture.
DX9 Swapchain can have it's parent window set to desktop, so it does not lose focus when moving to something else.
Having a focused window on top show little borders visible while moving it, but that is a bit more acceptable than losing everything.
Not future proof but guess will stay actual for a while.
3/Stay on Windows 7 and Disable DWM Service:
Doesn't work in Windows 8 anymore, but in my use case since most media companies I work for are still on Windows 7, it stays a valid solution for at least 5 to 10 years.
4/Force the DX11 Window on foreground
Basically continuously call SetForegroundWindow to avoid another window to take focus.
5/Prevent mode switch at presentation level.
Since on my application I got access to when presentation occurs, I use the following routine (before to call Present)
-Get Foreground window handle (using GetForegroundWindow), If Foreground handle is our fullscreen window, just call Present as usual.
If Foreground handle is not our fullscreen window, perform the following. Please note that visibility check is not needed, since even an invisible overlapping window will also cause a full screen loss! (seriously, this is just so bad...)
-Verify if our foreground window overlaps with the monitor:
Call GetWindowRect to get the bounds, and perform intersection with the monitor location.
Alternatively, call Present on the swapchain with the DXGI_PRESENT_TEST flag. If a window is overlapping, the Present call will return DXGI_STATUS_OCCLUDED
If a window overlaps, either Hide it or move it in another monitor (anywhere so it does not overlap):
ShowWindow and SetWindowPos are aperfect fit for this task.
Repeat that Test present call in a loop until it doesn't return the occluded status (this is important, since windows might not have processed the messages immediately); Once occluded flag is gone, call Present as usual.
There is a way to prevent DXGI from automatically leaving fullscreen mode when your process loses focus, though I must warn, it is a bit hackish.
Basically DXGI calls GetForegroundWindow() and checks if the returned window is yours.
If not, it switches off the fullscreen mode.
So if you hook/redirect this function to your own replacement, that always returns your window (regardless of whether it has the focus or not) - that will get the job done.
Here is a simple code that does that. It is for 64-bit mode and assumes that you NEVER need to call the real function, so it simply overwrites its start with a jump instruction to your replacement:
HWND WINAPI get_our_window()
{
return our_window;
}
void disable_automatic_leaving_fullscreen_on_lost_focus()
{
// get the address of GetForegroundWindow
char *p = (char *)GetProcAddress(GetModuleHandleA("user32.dll"), "GetForegroundWindow");
// make the function code writable
DWORD old;
VirtualProtect(p, 12, PAGE_EXECUTE_WRITECOPY, &old);
// overwrite the function start:
// mov rax, <address_of_GetOurWindow>
p[0] = 0x48, p[1] = 0xB8, *(void **)(p + 2) = (void *)get_our_window;
// jmp rax
p[10] = 0xFF, p[11] = 0xE0;
}
This code is only for demonstration.
If you need to retain the ability to call the true function, then you have to hook it in a different, more complicated way, but this is a separate subject

How can i draw to or add a custom button to every window of all applications?

I have seen several tools adding a custom button and/or drawing on the title bar of all windows of all applications in Windows. How is that done?
Extra points for an example in Delphi.
EDIT:
I found something for dotNET that does this:
http://www.thecodeking.co.uk/2007/09/adding-caption-buttons-to-non-client.html#.VdmioEDenqQ
How I see this job:
First of all we should be able to paint this button on the our own window caption. This procedure will be used later
This part of the program enumerates the active and visible windows
This part of the program using injection attach our dll to enumerated windows
From injected dll we can draw the button on the window caption
Inside this dll we should process the click on the button
We should have mechanism to send result to our main program
I haven't done this, so the following is what I would investigate if I were to try:
For each application / each top-level window:
Create a floating window and position it over the title bar wherever you want it to sit. Set up the parent / child relationship, but this window is part of your own process. (There are occasionally problems parenting a window from one process to one from another process, but try. I'd avoid injecting into other processes if possible.)
You can investigate the window flags to see if the window has a title bar (ie if you should add a button) via GetWindowLong with GWL_STYLE looking for WS_CAPTION. The same call will also let you see the type of caption / frame, which you can combine with GetSystemMetrics with, eg, SM_CYDLGFRAME to figure out the right size for your button on this specific window's title bar.
This window is now your button: paint, handle clicks etc as appropriate.
Make it a non-focusable window so that clicks to it don't take focus away from the window is is on the title bar of. You don't want clicking it to make the title bar change colour, for example. Do this by setting the WS_EX_NOACTIVATE window flag, something like: SetWindowLong(Handle, GWL_EXSTYLE, GetWindowLong(Handle, GWL_EXSTYLE) orWS_EX_NOACTIVATE).
The main problem is to keep it positioned correctly when the window moves, is resized, etc. To do this, install a hook for the system move events. You can also hook minimize and restore via EVENT_SYSTEM_MINIMIZESTART and EVENT_SYSTEM_MINIMIZEEND. This will allow you to keep track of all windows moving around onscreen, such that you can adjust the button-window position if necessary.
That gives you a window which you can paint as a button (and respond to clicks etc), that visually is "attached" to other windows so it stays in the same place as the user drags the title bar, minimizes or maximises the app, etc, and that is in your own process without cross-process problems.

Can a window be resized past the screen size/offscreen?

My purpose is to size a window to a width/height greater than the size of my physical screen programmatically under Win32. How can I do this?
On my systems it seems the maximum size of a given window is bound by the size of my screen whether programmatically or whether sizing manually by dragging the sizing cursor.
I have tried programmatically with SetWindowPos() and MoveWindow() and both cap the size of the target window. Oddly I know some people do not have this 'cap' so I wonder whether this is perhaps due to some OS setting (registry). Does anyone know something about this? Or perhaps some way to workaround it?
// Edit: new developments
I am testing on Windows XP and Windows 7. The graphics cards I'm using are a NVIDIA Quadro NVS 290 (256MB) and a Geforce 9800GT (1GB). After further investigation it looks like Windows is intercepting the message and fiddling with the parameters. For example, if you call SetWindowPos to make a target 2000x2000 it will only receive a WM_SIZE for the capped x/y.
Implement a message handler for WM_GETMINMAXINFO to stop Windows from applying the sane default behavior:
case WM_GETMINMAXINFO: {
DefWindowProc(hWnd, message, wParam, lParam);
MINMAXINFO* pmmi = (MINMAXINFO*)lParam;
pmmi->ptMaxTrackSize.x = 2000;
pmmi->ptMaxTrackSize.y = 2000;
return 0;
}
Windows with a thick frame (to allow user resize) are restricted from growing larger than the desktop.
Try SetWindowLong() clearing the THICKFRAME (0x40000) flag.
The following should allow programatic sizing, but the user will lose the ability to resize. If you add the Thickframe back after sizing, the user can resize, but when he does so the window will immediately shrink back to the desktop limited size.
The following is from some csharp code that also removes all borders, caption, etc:
WS style = (WS)GetWindowLong(ptr, GWL_STYLE);
style = style & ~WS.BORDER & ~WS.ThickFrame & ~WS.SYSMENU & ~WS.CAPTION | WS.POPUP;
SetWindowLong(ptr, GWL_STYLE, (int)style);
A good tool to play with window settings is uuSpy.
It's like Microsoft Spy++, but allows you to modify settings like THICKFRAME.
Yes, windows can be larger than the screen (or even the sum of all your monitors). Windows can also be positioned off-screen (which some applications do as a hack to hide while remaining active).
Perhaps the Windows 7 desktop manager is kicking in and trying to "dock" those windows to the edges of your screen for you.
You might try using the slightly lower-level API SetWindowPos, which gives you control over notifications, z-order, and other stuff.
You can get a window to be larger in resolution (and even way way larger) than your screen, using the 'Infinte Screen" software:
http://ynea.futureware.at/cgi-bin/infinite_screen.pl
Here's how to use it:
Download it, run it.
In the Oversize tab, choose the Windows you want to enlarge.
Give it the Width and Height you want. Done!
Just in case you need a large screenshot (that's how I ended up here):
If you want to get a screenshot of the window, you've got a screenshot option in the same Oversize tab. (Because screenshots are normally no bigger than the screen size, even if the window is larger). Another (and better) way to screenshot the window is using Greenshot, as you can save them in .tiff and directly watching the window.

Auto-Hide taskbar not appearing when my application is maximized

My application draws all its own window borders and decorations. It works fine with Windows taskbars that are set to auto-hide, except when my application window is maximized. The taskbar won't "roll up". It will behave normally if I have the application not maximized, even when sized all the way to the bottom of the screen. It even works normally if I just resize the window to take up the entire display (as though it was maximized).
I found the problem. My application was handling the WM_GETMINMAXINFO message, and was overriding the values in the parameter MINMAXINFO record. The values that were in the record were inflated by 7 (border width) the screen pixel resolution. That makes sense in that when maximized, it pushes the borders of the window beyond the visible part of the screen. It also set the ptMaxPosition (point that the window origin is set to when maximized) to -7, -7. My application was setting that to 0,0, and the max height and width to exactly the screen resolution size (not inflated). Not sure why this was done; it was written by a predecessor. If I comment out that code and don't modify the MINMAXINFO structure, the Auto-hide works.
As to why, I'm not entirely sure. It's possible that the detection for popping up an "autohidden" taskbar is hooked into the mechanism for handling WM_MOUSEMOVE messages, and not for WM_NCMOUSEMOVE. With my application causing the maximize to park my border right on the bottom of the screen, I would have been generating WM_NCMOUSEMOVE events; with the MINMAXINFO left alone, I would have been generating WM_MOUSEMOVE.
This is dependant on whether 'Keep the taskbar on top of other windows' is checked on the taskbar properties. If it's checked then the taskbar will appear.
But don't be tempted to programmatically alter this setting on an end users machine just to suit your needs, it's considered rude and bad practice. Your app should fit whatever environment it gets deployed to.

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