I would like to send some keystrokes from a C++ program into another window.
For that reason I would like to have the user select the target window similar to how it is done in the Spy++ utility that comes with Visual Studio (drag a crosshair cursor over target window and have target window highlighted by a frame).
How is this dragging and selecting done in Windows? I am completely lost as to where I might start to look for a mechanism to implement this feature.
Here's how it's usually done:
Capture the mouse using SetCapture. This will cause all mouse messages to be routed toward your app's window.
Handle the WM_MOUSEMOVE message. In your handler code, grab the window underneath the mouse using WindowFromPoint. That will get you the HWND of the window the mouse is currently over.
Now that you've got the window, you need a device context (HDC). You can get one using GetWindowDC for the specified window.
Now you can draw into the DC using typical GDI functions.
There are some things you have to look out for - cleanly erasing the selection rectangle and so forth, but that's one way to do it.
You could also draw into a screen DC to do this, but in any case you'll need the window handle in order to get the window rect.
If you Google around Spy++ source code you'll see a few examples of this technique.
Formers answers are wrong.
Spy++ source code has been given on G. Groups for years (see mainly Win32 api ng news://194.177.96.26/comp.os.ms-windows.programmer.win32)
Related
In windows: I would like to know if it is possible (and if so, how) to make a program in C++ that displays images/text on the screen directly, meaning no window; if you are still confused about what I am after some examples are: Rocketdock and Rainmeter.
you can do it certainly without using Qt or any other framework. Just Win32 API helps you do that and internally, every framework calls these API so there is no magic in any of these frameworks
First of all, understand that no image or text can be displayed without a window. Every program uses some kind of window to display text or image. You can verify it using the Spy++ that comes with windows SDK. click the cross-hair sign, click the image or text you think is displayed without any windows. The Spy++ will show you the window it is contained in.
Now how to display such image or text that seems like not contained in any window. Well you have to perform certain steps.
Create a window with no caption bar, resize border, control box, minimize, maximize or close buttons. Use the CreateWindowEx() and see the various windows style WS_EX_XXX, WS_XXX for the desired window style.
Once the window is there you need to cut the window. Much like a cookie cutter. for this you need to define an area. This area is called region and you can define it using many functions like CreateEllipticRgn(), CreatePolygonRgn(), CreateRectRgn(), CreateRoundRectRgn() etc. all these functions return a HRGN which is the handle to the region. Elliptical or rectangle regions are OK as starter.
Now the last part. You have to cut the window like that particular region. Use the SetWindowRgn() function which requires a handle to your window and a handle to that region (HRGN). This function will cut the window into your desired shape.
Now for the image or text. Draw the image or text inside the window. I assume you must have cut the window according to your image, You just need to give window a face. so just draw the image either on WM_ERRASE BACKGROUND or WM_PAINT messages
Use the SetWindowPos() to move the window to the location you wish to on screen. If you have used correct parameters in CreateWindowEx() then this step is not necessary
You can set any further styles of windows using SetWindowLong() function.
Congratulations, you have your image displayed without using any windows ;)
I need to draw an icon that moves approximately in sync with mouse cursor and is always on top of all windows.
OS: Windows 7
I have a solutions that work to some extend by drawing my icon in a top most transparent window. There are some major drawbacks in this solution since that top most window interferes with other top most windows and some full screen apps do not work correctly. Examples are start menu and task bar that will overlay my window if I do not regulary set it to be top most. For some full screen applications performance of updating position of window with icon hugely drops and it does not follow mouse smoothly.
There is another method that I came across where an icon is drawn directly to the device context of desktop Draw mouse pointer icon?. This solution has a drawback that there seems to be no good way of how to remove "trail", especially if desktop content changes quickly.
So my question: is there an ultimate solution that does not have the above mentioned problems?
Is it possible to draw above all windows in the "layer" of mouse cursor? Or make a second mouse cursor with my custom icon that I will control (I know that widows can display two independently controlled mouse cursors like CPNMouse)?
Can someone point me to the right direction?
Thanks!
Use a top-most window with transparency set via WS_EX_LAYERED / UpdateLayeredWindow.
If you set the WS_EX_TRANSPARENT style as well then the window won't intercept mouse input.
I have a program which is not written by me. I dont have its source and the developer of that program is developing independently. He gives me the HWND and HINSTANCE handles of that program.
I have created a child window ON his window, using win32 api.
First thing I need is to make this child window have transparency on some area and opaque on other area(like a Heads up display(HUD) for a game), so that the user may see things in both windows.
The second thing that I need is to direct all the input to the parent window. My child window needs no input.
I know that WS_EX_TRANSPARENT only makes the child draw at the end like in painters algorithm.
I cant use WS_EX_LAYERED because its a child window.
p.s.
I have looked everywhere but didn't find any solution though there were similar questions around the internet.
Actually this is a HUD like thing for that game. I can't draw directly on parent window because of the complexity with multi-threads any many other reasons.
-- EDIT ---------------------------
I am still working on it. I am trying different ways with what you all suggested. Is there a way to combine directX and SetWindowRgn() function or directx with BitBlt() function? I think that will do the trick. Currently I am testing all the stuff as a child window and a Layered window.
You can use WS_EX_LAYERED for child windows from Windows 8 and up.
To support earlier versions of windows, just create a level layered window as a popup (With no chrome) and ensure its positioned over the game window at the appropriate location. Most users don't move the windows they are working with all the time, so, while you will need to monitor for the parent window moving, and re position the HUD, this should not be a show stopper.
Not taking focus (in the case of being a child window) or activation (in the case of being a popup) is more interesting, but still quite do-able:- The operating system does not actually automatically assign either focus, or activation, to a clicked window - the Windows WindowProc always takes focus, or activation, by calling SetFocus, or some variant of SetActiveWindow or SetForegroundWindow on itself. The important thing here is, if you consume all mouse and non client mouse messages without passing them on to DefWindowProc, your HUD will never steal activation or keyboard focus from the Game window as a result of a click.
As a popup window, or a window on another thread, you might have to manually handle any mouse messages that your window proc does get, and post them to the game window. Otherwise, responding to WM_NCHITTEST with HTTRANSPARENT (a similar effect to that which WS_EX_TRANSPARENT achieves) can get the system to keep on passing the mouse message down the stack until it finds a target.
OK friends, finally I did some crazy things to make it happen. but its not very efficient, like using DirectX directly for drawing.
What I dis:
Used (WS_EX_TRANSPARENT | WS_EX_LAYERED | WS_EX_ TOOLWINDOW) and () on CreateWindowEx
After creating the window, removed (WS_EX_DLGMODALFRAME | WS_EX_CLIENTEDGE | WS_EX_STATICEDGE) from window styles, and also removed (WS_EX_DLGMODALFRAME | WS_EX_CLIENTEDGE | WS_EX_STATICEDGE | WS_EX_APPWINDOW) from extended window styles.
This gives me a window with no borders and its also now shown in the taskbar. also the hittest is passed to whatever that is behind my window.
Subclassed the window procedure of the other window and got the
WM_CLOSE,WM_DESTROY, to send the WM_CLOSE or WM_DESTROY respectively to my window
WM_SIZE,WM_MOVE, to resize and move my window according to the other window
WM_LBUTTONUP,WM_RBUTTONUP,WM_MBUTTONUP, to make my window brought to the top, and still keep focus on the other window, so that my window doesn't get hidden behind the other window
Made the DirectX device have two passes:
In the first pass it draws all the elements in black on top of a white background and copy the backbuffer data to an another surface (so it give a binary image of black & white).
In the second pass it draws the things normally.
Another thread is created to keep making the window transparency by reading that black & white surface, using the SetWindowRgn() function.
This is working perfectly, the only thing is it's not very good at making things transparent.
And the other issue is giving alpha blending to the drawn objects.
But you can easily set the total alpha (transparency) using the SetLayeredWindowAttributes() function.
Thanks for all the help you guys gave, all the things you guys told me was used and they guided me, as you can see. :)
The sad thing is we decided not to use this method because of efficiency problems :(
But I learned a lot of things, and it was an awesome experience. And that's all that matters to me :)
Thank You :)
You can make a hole in the parent window using SetWindowRgn.
Also, just because it is not your window doesn't mean you can't make it a layered window.
http://msdn.microsoft.com/en-us/library/ms997507.aspx
Finally, you can take control of another window by using subclassing - essentially you substitute your Wndproc in place of theirs, to handle the messages you wish to handle, then pass the remainder to their original wndproc.
I am writing Qt application which plays a fade-in animation whenever the mouse is moved to a certain area in the screen, and a fade out animation whenever the mouse is moved out of that same area.
I've already found a similar question here in stack overflow, however, it does not quite answer my question. (similar question here)
If I install an event filter to the application, will I be able to see ALL the events in the application even if it's outside my widget window?
If not, I am aware of an alternative involving QWidget::grabMouse() inside a reimplementation of leaveEvent(). But if I do so, will I be able to interact with anything OUTSIDE my application?
edit: though i am using the Qt library, my application is only for deployment to Windows.
I'm fairly the certain the answer is no, because events outside of your widgets are handled by the OSs window manager (and propagated onto whatever application is in that space).
However you can get the mouse position anywhere on the screen by calling QCursor::pos(), you could poll at regular intervals to find out where the mouse is.
You could try creating a completely transparent window that stays on top of the area where you want to receive mouse events, with the Qt::WindowStaysOnTopHint, Qt::FramelessWindowHint and Qt::ToolTip flags (the last one might prevent the window from receiving the focus), the Qt::WA_TranslucentBackground attribute and the mouse tracking enabled.
If you are on Windows, you can create a global hook to receive every mouse message (right before it's sent to the window under the mouse pointer). Unfortunately I don't know whether this functionality exists in other OSs.
I want to allow a user to drag my Win32 window around only inside the working area of the desktop. In other words, they shouldn't be able to have any part of the window extend outside the monitor(s) nor should the window overlap the taskbar.
I'd like to do it in a way that does cause any stuttering. Handling WM_MOVE messages and calling MoveWindow() to reposition the window if it goes off works, but I don't like the flickering effect that's caused by MoveWindow().
I also tried handling WM_MOVING which prevents the need to call MoveWindow() by altering the destination rectangle before the move actually happens. This resolves the flickering problem, but another issue I run into is that the cursor some times gets aways from the window when a drag occurs allowing the user to drag the window around while the cursor is not even inside the window.
How do I constrain my window without running into these issues?
Windows are, ultimately, positioned via the SetWindowPos API.
SetWindowPos starts by validating its parameters by sending the window being sized or moved a WM_WINDOWPOSCHANGING message, and then a WM_WINDOWPOSCHANGED message notifying the window proc of the changed size and/or position.
DefWindowProc handling of these messages is to, in turn, send WM_GETMINMAXINFO and then WM_SIZE or WM_MOVE messages.
Anyway, handle WM_WINDOWPOSCHANGING to filter both user, and code, based attempts to position a window out of bounds.
Keep in mind that users with multi-monitor setups may have a desktop that extends into negative x- and y-coordinates, or that is not rectangular. Also, some users use alternative window managers such as LiteStep, which implement virtual desktops by moving them off-screen; if you try to fight this, your application will break for these users.
You can do this by handling the WM_MOVING message and changing the RECT pointed to by the lParam.
lParam: Pointer to a RECT structure with the current position of the window, in screen coordinates. To change the position of the drag rectangle, an application must change the members of this structure.
you may also want to handle WM_ENTERSIZEMOVE to know when the window is beginning to move, and WM_EXITSIZEMOVE
WM_GETMINMAXINFO is what you seem to be looking for.