On 22/10/2018 22.37, John Weeks wrote:
We faced pretty much exactly this issue when we ported our very large
application to Qt, starting with Qt 4.8. We have many places where we expect to
be able to walk a window list in Z order. I wound up using Activate/Deactivate
events to keep the list myself. I can't really recommend it- it has been pretty
much of a nightmare to make it robust and bug-free, especially as Qt has a
couple of bugs in their own notion of window activation. You can't really use
the debugger to debug these issues, as the activation of the debugger changes
the activation of the application's windows.
I have made it work pretty well, but I quake in my boots whenever I get a bug
report about window order.
We are now using Qt 5.9 and don't have any sort of replacement for my delicate
and difficult code.
-John Weeks
WaveMetrics, Inc.
On Oct 22, 2018, at 11:37 AM, Israel Brewster <ibrews...@flyravn.com> wrote:
I have an application (Qt 5.9) that has a variety of different types of windows
you can open. If a user selects to open a type of window that is already open,
I want to position the new window relative to the existing one. I can easily
find any existing windows of a given type by going through the list of widgets
in QApplication::allWidgets(), doing a qobject_cast to the proper type, and
checking the result, but is there a way to determine which of these is the
frontmost of that type? QApplication::ActiveWindow() doesn't help, because the
activeWindow may not be of that type.
....
Hi, just an idea, but obviously somewhere deep inside Qt's bowels
(rather, the painting system) there's knowledge of which window obscures
which etc.
Say you issue a dummy QWidget::update() on your topmost/app window, then
catches all the QPaintEvents that are called. Inside those QPaintEvents
is a QPaintEvent::rect() that holds the rectangle that needs to be
updated/repainted. If you then search your QApplication::allWidgets()'s
list of rectangles; then I think (guessing) that only the
topmost/foremost windows will match QPaintEvent's rectangles. I.e.
windows that are partially or fully obscured by another window should
receive a smaller (or none) rectangle in those QPaintEvents. That could
be one way to establish a z-order on the fly...
Rgrds Henry
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