tdf#165099: do not notify change listeners about temporary changes

Commit bc09a4f1ce1f6a714f7827a404aa6317b503d307 (Disable subpixel AA
in GraphicExporter::filter unconditionally, 2024-12-04)  had changed
GraphicExporter::filter  to set application settings unconditionally,
instead of only when AA was explicitly set. That uncovered a problem
that the change may trigger a rebuild of sidebars;  and in slideshow
case, it may make the rebuilt sidebars to capture the temporary view
created for the slideshow.

1. Slideshow is built; in SlideShow::StartFullscreenPresentation, it
creates a new component with a frame,  which eventually creates a
new sd::DrawController;
2. Slideshow draws its slide(s); in slideshow::internal::getMetaFile,
GraphicExporter::filter is called, which would change application
settings;
3. Application::SetSettings eventually trigger WindowEventHandler in
sfx2::sidebar::SidebarController, with WindowDataChanged;
4. SidebarController::maContextChangeUpdate is called asynchronously,
i.e.,  after all the draw is finished;  eventually this will call
SidebarController::UpdateConfigurations for SdSlideTransitionDeck,
which forces rebuild of the deck;
5. sd::SlideTransitionPane::Initialize  resets its mxView to current
controller, which is the sd::DrawController created on step 1 for
the slideshow;
6. sd::SlideShow::end closes its frame, eventually disposing frame's
controller (calling sd::DrawController::dispose);  note that this
controller is still referenced from sidebar.

After that, the sidebar interactions will crash because of unhandled
exception thrown from DrawController::ThrowIfDisposed.

Note that the change in the abovementioned commit only uncovered the
problem; before that change it could still crash, when AA was set in
the GraphicExporter::filter call.

This change makes sure to not notify listeners in the #3 above, when
the change of the settings is only temporary  (for the duration of a
export). This is similar to the existing bTemporary argument that is
already passed to SetAntiAliasing from GraphicExporter::filter. This
allows to avoid the unwanted sidebar rebuild;  and also, this should
improve the filter call performance. The hope is, that this wouldn't
modify the result; but if some components, that listen to the change
notifications, happen to affect the export,  we likely would need to
change their behavior to always use Application::GetSettings.

It seems to me, that after this change, clicking the first time on a
transition after a slideshow will not select it.  Seems like another
pre-existing problem;  it flickered before selection even before the
change; likely needs a separate fix.

Change-Id: Ia0ba19401ca805c2190926623c1c708cf26a313b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/181288
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

0 files changed, 0 insertions, 0 deletions