The basic idea is: I would like to draw over everything on the screen.
One way I can imagine this is creating a transparent full-screen window without window controls (minimise, maximise, etc.) or borders. Then drawing into that window which is transparent. The problem I can think of is that I will be unable to control windows which are behind our transparent window.
How could I do something similar to this, without the mentioned problem? I would also like it to work on multiple operating systems if possible.
Edit:
The user will not be drawing with the mouse or other means on the screen, but will be able to continue use his desktop like normal, without that my program interferes in any way (other than the drawing on the screen). My program will only display something on the screen, which the user will be unable to interact with (at least that's the plan).
Qt 5 implements it:
QWidget w;
w.setWindowFlags(Qt::WindowTransparentForInput);
Qt 4 didn't support this functionality yet - see QTBUG-13559. The bug report had a hint on what needed to be done for Windows.
The method you describe is the one to use; a transparent full-screen window.
If you're using the left mouse button to draw, you'll need a mechanism of switching modes to be able to select items through the window and send events to the operating system.
Related
I have a 2-monitor setup and when I spawn a QInputDialog it always spawns in the left monitor, ie the one I generally dont use that much. Is there a way to indicate to appear in the monitor I have focus without incurring in any (x,y) positioning stuff.
Basically I dont care where it appears as long as it the monitor with focus.
You can use QDesktopWidget (http://doc.qt.io/qt-5/qdesktopwidget.html) to find out which screen your MainWindow is being displayed on. This is going to be the screen with "the focus", I assume.
You then use the screen number to find out the geometry of the screen and place place the QInputDialog in the screen's center - either before the dialog is shown or right afterwards.
I'm afraid this solution is using "(x,y) positioning stuff", but if you find a way to place the dialog without it, let me know.
[qt 4.8]
To get correct window dimensions including its frame, I do the following (as described e.g. here, see comment from Daniel Hedberg).
mainWindow.move(-50000, -50000);
mainWindow.show();
// do something with the window dimensions
mainWindow.move(0, 0);
mainWindow.show()
This works fine, however, I have a problem with the move(0,0) call: It makes the window always appear at position (0,0), while I would like to have the default behaviour, this is, the application only suggests to the window manager that (0,0) is a good place to position the window, and the WM might decide to shift it if necessary to avoid overlapping. In other words, I would like to switch back to Qt's default behaviour as if there weren't a call to move at all.
How can I do that?
One solution is to store Windows original position and use that. For extra safety (in case screen resolution changes), check that entire window still fits on screen and move and even resize if it does not.
A hacky alternative would be to create and open empty, possibly transparent dummy window of the same size and see where it gets positioned. Then move the original there and close the dummy one. Reading your question carefully, I think this would do what you are after.
I don't know of a Qt way to ask Window Manager to reposition the window, so if you really need that, specify the OS etc details.
Looking into the source code of Qt, I can now partially answer my own question: To convert a call to move into a suggestion for positioning instead of a request, do this:
mainWindow.move(100, 100);
mainWindow.setAttribute(Qt::WA_Moved, false);
mainWindow.show();
I've tested the code under X11 using Qt 4.8.4, and hopefully it works with on other platforms too.
Unfortunately, this doesn't solve the very problem I have, namely to use show to get the (decorated) dimensions of an off-screen window which then gets moved to the screen, calling show again. It seems that the first call to show directly sets platform-specific window manager flags which aren't completely reset and reevaluated in the second call. Actually, I'm going to think that this is a bug in Qt, so I'll report it accordingly.
I am using Qt and creating a GUI with multiple sub windows. I am using MDI Area for the same. I want to hide the top toolbar of mdi subwindow but using window flags is not helping.
I have tried writing the code as follows. First I tried for mdiarea and then for subwindow but neither worked.
mdiarea.setWindowsFlags(Qt::FramelessWindowHint);
subwindow.setWindowsFlags(Qt::FramelessWindowHint);
I have also tried using Qt::CustomizedWindowHint but even that is not helping. Please help me with this.
Thank You.
Try this:
mdiArea->addSubWindow(new QLabel("Qt::FramelessWindowHint"), Qt::FramelessWindowHint);
You don't want to set the MDI area itself as a frameless window, because it's a widget you likely have embedded in another window... it most likely already doesn't have a frame.
Your setting the 'subwindow' should work... but addSubWindow(myWidget) actually wraps the widget passed in in the real subwindow, so that's what was going wrong. Qt lets you pass in window flags as the second parameter of addSubWindow() and those flags go to the real subwindow.
Note that with a frameless window, you can't drag the window around to move it, or grab the edges to resize it, because there's nothing for you to grab onto!
If you just want the minimize and maximize buttons gone (but still want the close button), try passing Qt::Dialog instead.
Try also experimenting with these:
addSubWindow(new QLabel("Qt::Tool"), Qt::Tool);
addSubWindow(new QLabel("Qt::Tool|Qt::CustomizeWindowHint"), Qt::Tool|Qt::CustomizeWindowHint);
addSubWindow(new QLabel("Qt::Dialog"), Qt::Dialog);
I think Qt::Tool|Qt::CustomizeWindowHint is probably the best option (no buttons, but still movable and resizable - if you don't want it resizable, give it a fixed size (setFixedSize()).
Edit: Also try: Qt::CustomizeWindowHint|Qt::WindowTitleHint
Anyone know how to create animated auto-hide on ApplicationControlBar just like Windows's taskbar?
I'm totally new on this.
Thanks.
The issue with doing this is that on Windows, you have a 'lower bound'--also known as the bottom of the screen which is used to trigger the display of the task bar based on the mouse location.
In a browser based app, you don't have that spot which is easy for the user to roll their mouse over.
That said, if you're still adamant, you should be able to put something together easily using the mouse over events to swap the visibility of the ApplicationControlBar and then you can use show / hide effects to display the control bar.
is it possible to use the startMove Method in AS3 and limit the movement only to the y-axis?
I want my window only to be dragable vertically.
Thank you for your tips.
I don't think that is possible, given that the actual movement of the window is done by the operating system alone (and I can't think of any application right now that restricts such a movement).
But maybe you can emulate such behaviour by encapsulating your actual application into a different window. You could then change the actual application size to the full screen and make it transparent and use startDrag to emulate the dragging of the inner window. Because with that function you can specify boundaries in which the movement is allowed.
I don't know if that will work as you would like it to, however.