This issue presented after the following sequence of steps:
- Display a window with a non-native titlebar
- Maximise it
- Click the taskbar icon to minimise it
- Click the taskbar icon again to maximise it
After being maximised for the second time, the window bounds were too
large for the display. This is because the check in WM_NCCALCSIZE was
failing to determine the target monitor for the window, and therefore
failing to adjust the new area appropriately. We now determine the
target monitor based on the proposed new bounds of the new window,
rather than the current bounds of the window, which may not be
meaningful if the window is minimised.
On at least iOS 26 using a temporary window frame is unreliable. This
change tries to use an existing window for any non-standalone app. It
also updates the details on any changes, such as when the device
orientation changes.
handlePositionChanged() is called when the window changes z-order, which
may cause a new mouse event to be synthesised if the mouse is over the
window after the z-order is updated. In this situation, we may not have
received a mouse up/down/move event to update the current modifier
flags, so we need to update them ourselves.
This is a different approach to the change introduced in
04f87320d5.
Instead of completely recreating the window, we now just update the
window's style flags. This should ensure that window and component focus
are preserved.
This follows on from the work in
3e70c37ce3.
The previous patch had the intended effect as long as the peer was
recreated after entering kiosk mode. However, for windows initially
created with non-native titlebars, attempting to disable the titlebar
would have no effect.
We now check whether the native style flags would need to change as a
result of changing kiosk mode, and recreate the peer if necessary.
467f20a7a1 introduced a change to start processing WM_NCMOUSELEAVE
messages as mouse-exit events. This behaviour is not quite correct,
because NCMOUSELEAVE may be triggered when moving the cursor from the
nonclient area to the client area, in which case the mouse is still over
the window.
We now check whether the mouse is really over the window inside
doMouseExit(), and continue to track it if necessary.
This bug could be observed by running the WidgetsDemo Drag+Drop pane on
Windows 10, and dragging an item between two displays at different scale
factors.
This is issue is a regression introduced in
9817a2bb66. The regression was caused by
the change in mouse position calculation. The incorrect version switched
to using ClientToScreen, but the correct version used
getPointFromLocalLParam.
The function getPointFromLocalLParam was replaced by clientLParamToPoint
in 24ab3cb6a3, and is restored by this
commit.
This change intends to address a bug observed only on Windows 10 with a
display scale factor of 125%.
When the native titlebar is enabled, and the window's border-resizer is
used to resize the window slowly the with mouse, the client area of the
window may move to the wrong location, or be drawn with some areas
obscured/clipped. This is especially observable when resizing the
WidgetsDemo to its smallest size, and then dragging the right border a
single pixel to the right. On my computer, this consistently causes the
client area to display at the wrong location.
I haven't been able to find any obvious bug in JUCE that might cause
this behaviour. In particular, it seems that the window begins
displaying incorrectly *before* the window ever actually resizes.
During the resize, the system sends events (WM_SIZING and
WM_WINDOWPOSCHANGING) to the window, and according to the documentation,
the window may modify the message parameters in order to constrain the
new window size. When running on a scaled display, JUCE attempts to map
the logical client area size to a sensible size in physical pixels, and
uses the sizing messages to enforce this size requirement.
In the case of the broken window rendering, the system requests a new
window size, which JUCE rejects. The window's display state doesn't
change, so the swap chain does not resize, and the swap chain does not
present. Put another way, the broken rendering happens *independently*
of JUCE modifying the swap chain in any way. Therefore, I believe that the
bug is introduced elsewhere, potentially by Windows itself.
I also checked to see whether the issue could be caused by mishandling
of the NCCALCSIZE message, which is normally used to configure the
relative positions of the client and nonclient areas. However, in the
buggy case, NCCALCSIZE is not sent until *after* the first 'broken'
frame is painted - and even then, the implementation immediately falls
back to DefWindowProc.
Given that the issue appears to be a bug in Windows, the proposed change
is a workaround, rather than a true fix. It appears as though the
problem goes away when WM_WINDOWPOSCHANGING does not modify the
requested bounds. Therefore, for windows with native titlebars, we rely
on the constraints to be applied in WM_SIZING only, when sizing the
window in a sizemove gesture.
Previously, for windows with a native titlebar and a constrainer, the
window could be restored at the wrong size. This happened because
findPhysicalBorderSize() may return nonsensical values when called
during a SC_RESTORE, which in turn produces an unexpected window size
when adding the bogus border size to the constrained client area size.
We now avoid trying to constrain the window if we're unable to determine
the correct border size. I think this is only likely to happen during
SC_RESTORE, in which case the system should have a pretty good idea of
where the window should go, and constraining should not be necessary.
The buggy behaviour could be seen in a blank GUI app project by setting
a native titlebar and calling setResizable (false, false). The resulting
window would still display a resize cursor when hovering the window
border.
