diff options
author | Morten Johan Sørvig <morten.sorvig@qt.io> | 2016-01-21 10:33:45 +0100 |
---|---|---|
committer | Tor Arne Vestbø <tor.arne.vestbo@qt.io> | 2017-07-11 15:25:00 +0000 |
commit | ecac1aeb29f37a080d4f2d3614bfc5fcc5b70689 (patch) | |
tree | 0bb1f62818a870e8f287558d56935762a6187a07 /src/gui/kernel | |
parent | a6991376cc4c7084a151272d7e27a5140597cc9e (diff) |
Document expose event behavior
Document that "visible"-but-obscured windows may not
get expose events for various audiences: QTestLib
users, platform plugin authors and on the QExposeEvent
itself. QWindow::exposeEvent() already has this documented
and is not changed.
Task-number: QTBUG-50414
Change-Id: I91042e8b1c70e48f10e692b2e80367d242a8ccbe
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Diffstat (limited to 'src/gui/kernel')
-rw-r--r-- | src/gui/kernel/qevent.cpp | 6 | ||||
-rw-r--r-- | src/gui/kernel/qwindowsysteminterface.cpp | 17 |
2 files changed, 22 insertions, 1 deletions
diff --git a/src/gui/kernel/qevent.cpp b/src/gui/kernel/qevent.cpp index 680acb16e7..5000cc35dd 100644 --- a/src/gui/kernel/qevent.cpp +++ b/src/gui/kernel/qevent.cpp @@ -1525,7 +1525,11 @@ QMoveEvent::~QMoveEvent() \ingroup events Expose events are sent to windows when an area of the window is invalidated - or window visibility in the windowing system changes. + or window exposure in the windowing system changes. + + A Window with a client area that is completely covered by another window, or + is otherwise not visible may be considered obscured by Qt and may in such + cases not receive expose events. The event handler QWindow::exposeEvent() receives expose events. */ diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp index 233c27dee7..e2087bd22f 100644 --- a/src/gui/kernel/qwindowsysteminterface.cpp +++ b/src/gui/kernel/qwindowsysteminterface.cpp @@ -303,6 +303,23 @@ QWindowSystemInterfacePrivate::ExposeEvent::ExposeEvent(QWindow *window, const Q { } +/*! \internal + Handles an expose event. + + The platform plugin sends expose events when an area of the window + is invalidated or window exposure changes. \a region is in window + local coordinates. An empty region indicates that the window is + obscured, but note that the exposed property of the QWindow will be set + based on what QPlatformWindow::isExposed() returns at the time of this call, + not based on what the region is. // FIXME: this should probably be fixed. + + The platform plugin may omit sending expose events (or send obscure + events) for windows that are on screen but where the client area is + completely covered by other windows or otherwise not visible. Expose + event consumers can then use this to disable updates for such windows. + This is required behavior on platforms where OpenGL swapbuffers stops + blocking for obscured windows (like macOS). +*/ QT_DEFINE_QPA_EVENT_HANDLER(void, handleExposeEvent, QWindow *window, const QRegion ®ion) { QWindowSystemInterfacePrivate::ExposeEvent *e = |