How to know the name/ID of window in focus specifically in OpenCV.
Is there any event handling/callback or windows api that make this possible if it is not possible with OpenCV.
I am working on Windows 7 and 8.1.
I want to do something similar to (but not limited to):
If a window is in focus, and some event like mouse or key press happens,
then update that particular window
.
As suggested by Kris, there exists a solution on window. Use windows api to take handle of active window as using:
HWND WINAPI GetActiveWindow(void);
Now use GetWindowText() function to extract out title, if any. It may not be portable. There should exist similar api for other OS.
first of all, I don't know if windows or any other api can help.
I have an idea to take screen-shot, somehow, and then use opencv itself for image processing. Assumption is that the focused window will be on the top and most focused so we can see the name easily. We can process color to separate focused window from others, if any. And using OCR to extract windows name.
Related
Is it possible to create a keyboard shortcut to switch between the monitor and portion selection of this wacom preferences window, via a c++ console program?
Sorry if this is poorly worded, I've had trouble trying to find the right words to search for ways to do it.
I think it should be possible, although a bit tedious. You should be able to use the Windows API, and try to EnumWindows/EnumDesktopWindows to identify the respective application Window, and its respective controls (which are also Windows).
You should identify the window title, and class ids, for the app window, and the checkbox button controls, then when you enumerate through all the desktop windows, you can identify the ones you are interested in.
Then you can use the SendMessage() API to send messages to the controls (Windows) of interest to manipulate them.
It's a bit tedious, but sounds possible.
An example of use here to get an idea:
http://www.cplusplus.com/forum/windows/25280/
Here is a description of my use case:
I have a Windows application that comprised of the main window and it also creates child windows (think of MS Word for instance). What i want to do is draw frames around certain children windows of a given application. Note that when i say window i mean any visible HWND (handle) in the system. This could be a certain window in Excel, or an open pdf document in Abode reader or whatever.
My question is:
Can this be implemented as AN independent API where one would for instance be able to call the following ?
DrawOutline(HWND, OutlineColor, Thikness);
Any pointers as to how to approach this ? Any limitations one might think of? This would not be a plugin to a specific application but a stand alone API. MFC is also OK. Thanx
The Spy++ tool draws frames around any window. Source code for several Spy++ versions is available on the net.
I am new to Windows programming, mostly done Java(Java SE, Java ME, Android, Java EE), so be detailed and gentle.
I want to capture "the name of the file/path that was clicked in windows, like clicking a file on the desktop"?
Further research http://www.codeproject.com/Articles/6362/Global-System-Hooks-in-NET, which is a small c#/c++ nice app that uses Global System Hooks, to capture mouse events such as coordinates,clicks,etc.
So what is the right API or Global System Hook that captures events on file icons?
There is no single API that provides that level of detail.
The WH_MOUSE and WH_MOUSE_LL hooks of SetWindowsHookEx(), or the WM_INPUT message delivered by RegisterRawInputDevices(), can tell when the mouse is being intereacted with, and the GetCursorPos() function can tell you where the mouse cursor is located onscreen at the time of a click, but it cannot tell you what it is clicking on. You have to figure that out manually.
For instance, the Desktop is implemented as a ListView control, so you can use the WindowFromPoint() and GetDesktopWindow() functions to check if the mouse is located at coordinates corresponding to the desktop window itself instead of an application window, and if so then use the LVM_HITTEST and LVM_GETITEM messages to determine which icon onthe desktop is being clicked on and extract its display text. Then use the SHGetDesktopFolder() function and the IShellFolder interface, or the SHParseDisplayName() function, to parse that text and see if it returns a PIDL that represents a path/file, and if so then use SHGetPathFromIDList() to get the actual path/file name.
If you want to do the same thing with the Windows Explorer app, it gets a bit more complicated. Use WindowFromPoint(), GetWindowThreadProcessId(), OpenProcess(), and EnumProcessModules() to determine if the mouse is over the Windows Explorer app. However, its UI changes from on Windows version to the next, but the jist is that you have to manually locate the focused control via AttachThreadInput() and GetActiveWindow(), check if it is a TreeView/ListView control, and if so then use control-specific messages to get information about the item/icon underneath the mouse cursor coordinates, and use IShellFolder again to figure out what the text of that item/icon actually represents.
Shell programming is very complex system and not for the feint of heart to interact with. So you need to ask yourself, why do you need this information in the first place?
The Windows API provides an API GetDesktopWindow( ) which returns the window handle
But I tested with Spy++ and I find that the window handle of the desktop and the window handle of the "Windows Desktop" is not the same.
As the "Windows Desktop" is a list view, do I need to do the following
1) HANDLE hWnd = GetDesktopWindow() ;
2) FindWindow(hWnd, ..... ) with the SyslistView32 as the Window class.
Once I get the Window handle, I want to use SendMessage() for operations like getting selected file name, the number of files selected , etc.
Please give your opinions. I am doing this using the Windows SDk
In light of a recent discussion on Meta complaining that questions like this one have "not been properly answered", I'm going to try and give answering this one a whirl. Not to imply that I think meklarian's answer is bad—in fact, far from it. But it's clearly been deemed unsatisfactory, so perhaps I can fill in some of the additional details.
Your problem results from a fairly widespread confusion over what the desktop window actually is. The GetDesktopWindow function does precisely what it's documented to do: it returns a handle to the desktop window. This, however, is not the same window that contains the desktop icons. That's a completely different window that appeared for the first time in Windows 95. It's actually a ListView control set to the "Large Icons" view, with the actual desktop window as its parent.
Raymond Chen, a developer on the Windows Shell team provides some additional detail in the following Windows Confidential article: Leftovers from Windows 3.0
[ . . . ] While in Windows 3.0, icons on the desktop represented minimized windows, in Windows 95, the desktop acted as an icon container.
The Windows 95 desktop was actually a window created by Explorer that covered your screen (but sat beneath all the other windows on your desktop). That was the window that displayed your icons. There was still a window manager desktop window beneath that (the window you get if you call GetDesktopWindow), but you never saw it because it was covered by the Windows 95 desktop—the same way that the wood paneling in the basement of my colleague’s house covered the original wall and the time capsule behind the wall.
[ . . . ]
This desktop design has remained largely unchanged since its introduction in Windows 95. On a typical machine, the original desktop is still there, but it’s completely covered by the Explorer desktop.
In summary, then, the window returned by the GetDesktopWindow function is the actual desktop window, the only one we had way back in Windows 3.0. The Explorer desktop (the one that contains all your icons) is merely another window sitting on top of the desktop window (although one that completely covers the original) that wasn't added until Windows 95.
If you want to get a handle to the Explorer desktop window, you need to do some additional work beyond simply calling the GetDesktopWindow function. In particular, you need to traverse the child windows of the actual desktop window to find the one that Explorer uses to display icons. Do this by calling the FindWindowEx function to get each window in the hierarchy until you get to the one that you want. It has a class name of SysListView32. You'll also probably want to use the GetShellWindow function, which returns a handle to the Shell's desktop window, to help get you started.
The code might look like this (warning: this code is untested, and I don't recommend using it anyway!):
HWND hShellWnd = GetShellWindow();
HWND hDefView = FindWindowEx(hShellWnd, NULL, _T("SHELLDLL_DefView"), NULL);
HWND folderView = FindWindowEx(hDefView, NULL, _T("SysListView32"), NULL);
return folderView;
I noted there that I don't actually recommend using that code. Why not? Because in almost every case that you want to get a handle to the desktop window (either the actual desktop window, or the Explorer desktop), you're doing something wrong.
This isn't how you're supposed to interact with the desktop window. In fact, you're not really supposed to interact with it at all! Remember how you learned when you were a child that you're not supposed to play with things that belong to other people without their permission? Well, the desktop belongs to Windows (more specifically, to the Shell), and it hasn't given you permission to play with its toys! And like any good child, the Shell is subject to throwing a fit when you try to play with its toys without asking.
The same Raymond Chen has published another article on his blog that details a very specific case, entitled What's so special about the desktop window?
Beyond the example he gives, this is fundamentally not the way to do UI automation. It's simply too fragile, too problematic, and too subject to breaking on future versions of Windows. Instead, define what it is that you're actually trying to accomplish, and then search for the function that enables you to do that.
If such a function does not exist, the lesson to be learned is not that Microsoft simply wants to make life harder for developers. But rather that you aren't supposed to be doing that in the first place.
If you want the Desktop window as defined in GetDesktopWindow(), use that window handle. This is the window handle you should use to look for top-level windows and other related activities.
What you're seeing in Spy++ is just the content drawn as the desktop in your session. If you use the auto-locate in Spy++, you'll see that the SysListView32-declared window is a child window of your explorer shell. It is quite infrequent for someone to need access to this window. Also, the existence of this window may be subject to changes between versions of windows.
Edit (additional info)
If you are looking to interact or place things on the actual shell desktop, you may be better served by other APIs. Here are two such APIs that can accomplish this, depending on the target version of windows.
Windows Sidebar # MSDN
This is available on Vista and Windows 7
Using the Active Desktop # MSDN
This is available on Windows 2000 and XP, although frequently disabled by users and sysadmins.
I have a written a Visual C++ console application (i.e. subsystem:console) that prints useful diagnositic messages to the console.
However, I would like to keep the application minimized most of the time, and instead of minimizing to the taskbar, appear as a nice icon on the system tray. I would also like to restore the console when the system tray icon is clicked.
How should I change my program to do this?
This is going to be an ugly hack.
First, you have to retrieve the hWnd / hInstance of you console application. Right now, I can only come up with one way:
Create a Guid with CoCreateGuid()
Convert it to a string
Set the title of the console window to this guid with SetConsoleTitle()
Find the hWnd of the your window with the Guid as the tile with FindWindow()
And you can do it from the usual way from this point. See http://www.gidforums.com/t-9218.html for more info.
Don't forget the rename your console window to the original title once you're done.
As you can see, even though this is possible to do, it's a horrible and painful solution. Please don't do it. Please do not minimize console applications to the system tray. It is not something you are supposed to be able to do in the Windows API.
You might want to write a separate gui to function as a log reader. You will then find it much easier to make this minimize to the tray. It would also let you do some other stuff you might find useful, such as changing which level of logging messages are visible on the fly.
To learn the console's hWnd you have two choices:
On Windows 2000 or later you can use the GetConsoleWindow() function. Don't forget to define _WIN32_WINNT as 0x0500 or greater before including windows.h to have access to this function.
If you want to run your program on earlier Windows versions as well then you must use something like the GUID trick described above.
Probably your best bet is to create a "Message-only window" (a message queue without a visible window) to receive the Notification Area messages.
The answer with a GUID is completely ridiculous (no sense at all)
The Console hWnd is of course given by GetConsoleWindow() (!)