I'm pretty sure QPainterPath is reentrant especially since QPainter depends on QPainterPath and QPainter is reentrant.
On Tue, Dec 6, 2016 at 5:56 PM Ch'Gans <chg...@gna.org> wrote: > On 7 December 2016 at 01:18, Philip Schuchardt <vpica...@gmail.com> wrote: > > Since QGraphicsView can only render in the main gui thread, rendering in > a > > separate process will prevent the blocking on the main thread. You could > > even implement "big pixel" zooming. You zoom in on the visible buffer > while > > a back buffer is being rendered in the background by the separate > process. > > This approach doesn't optimize the rendering. It just prevents the main > gui > > thread from being blocked by the rendering. It would be great if you > could > > render QGraphicsScene in a non-gui thread, but as far as I can tell you > > can't. > > I see what you mean now, I forgot about the main gui thread restriction... > > So how one know if a GUI Class that is not directly related to QWIdget > can be used or not outside the main gui thread? > I'm thinking about classes such as QFontMetric, QPainter, QPixmap, ... > and generally speaking any off-screen rendering component (inc. PDF, > ...) > > Should the absence of the usual re-entrant note near the top of the > documentation page be taken as "Main GUI thread only"? > Eg: QList and QPainter have "Note: All functions in this class are > reentrant.", but QPainterPath doesn't (!?!). > > Chris > > > > > On Tue, Dec 6, 2016 at 4:25 AM Ulf Hermann <ulf.herm...@qt.io> wrote: > >> > >> Hello, > >> > >> I had a somewhat similar, but not quite the same problem when building > the > >> timeline view for the QML profiler in Qt Creator. It's currently usable > with > >> up to about 1 million events in the timeline and you can zoom and > scroll it. > >> There might be potential for further optimization. I used the Qt Quick > >> SceneGraph API to directly work with OpenGL geometry. The scene graph > nodes > >> are built on demand and then cached and recycled when applicable. You > can > >> check out the result in the Qt Creator sources in src/libs/timeline. > >> > >> br, > >> Ulf > >> _______________________________________________ > >> Interest mailing list > >> Interest@qt-project.org > >> http://lists.qt-project.org/mailman/listinfo/interest > > > > -- > > Phi|ip > > > > _______________________________________________ > > Interest mailing list > > Interest@qt-project.org > > http://lists.qt-project.org/mailman/listinfo/interest > > > -- Phi|ip
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