Re: [Development] New high-dpi QPen proposal (Was Re: Proposal: Make QPen non-cosmetic by default)
On Thursday 18 October 2012 09:59:45 Samuel Rødal wrote: In summary (or TL;DR), my new proposal would be to just make QPainter::NonCosmeticDefaultPen work as advertised, and have it be set by default when high-dpi mode is enabled. This way there would be minimal breakage of existing code. Thoughts? Making this opt-in as you describe sounds a safer option from the perspective of application and middle-ware developers with existing code-bases. So +1 from me. Sean -- Dr Sean Harmer | sean.har...@kdab.com | Senior Software Engineer Klarälvdalens Datakonsult AB, a KDAB Group company Tel. Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) KDAB - Qt Experts - Platform-independent software solutions ___ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development
Re: [Development] New high-dpi QPen proposal (Was Re: Proposal: Make QPen non-cosmetic by default)
Maybe as a best effort we could introduce a different render hint, asking QPainter to treat cosmetic pens as geometric, would be a better solution for Morten's high-dpi use case. Then it would be opt-in instead of opt-out, and no existing applications would be affected. Turning on high-dpi mode could be documented to also set the render hint. ... In summary (or TL;DR), my new proposal would be to just make QPainter::NonCosmeticDefaultPen work as advertised, and have it be set by default when high-dpi mode is enabled. This way there would be minimal breakage of existing code. Thoughts? No I don't think this would work. That way we will get the obscure scalability issues that Uwe mentioned but it would only happen on retina capable computers so it can become even harder to discover. The original proposal doesn't really have these problems though. We already set the render hint NonCosmeticPenByDefault on GraphicsView to avoid inconsistent scalability issues there and keep style code working when being scaled. I think we should extend this behavior to QPainter in general by only initialising QPen to 1 instead of 0. We keeping the explicit 0-pen working as before. In addition, we introduce a CosmeticPenByDefault render hint that Qwt can set on its painter to make all pens cosmetic by default. (not just 0-pen) Though the Qt4PainterRenderHint could still explicitly give only 0 pen cosmetic properties. This should have a very minimal impact on existing code, while at the same time addressing the fact that most code written with the implicit QPen constructor in mind, does not expect a cosmetic pen. Or the pen to change by simply setting a different width on it. Jens ___ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development
Re: [Development] New high-dpi QPen proposal (Was Re: Proposal: Make QPen non-cosmetic by default)
On 10/18/2012 11:08 AM, Bache-Wiig Jens wrote: Maybe as a best effort we could introduce a different render hint, asking QPainter to treat cosmetic pens as geometric, would be a better solution for Morten's high-dpi use case. Then it would be opt-in instead of opt-out, and no existing applications would be affected. Turning on high-dpi mode could be documented to also set the render hint. ... In summary (or TL;DR), my new proposal would be to just make QPainter::NonCosmeticDefaultPen work as advertised, and have it be set by default when high-dpi mode is enabled. This way there would be minimal breakage of existing code. Thoughts? No I don't think this would work. That way we will get the obscure scalability issues that Uwe mentioned but it would only happen on retina capable computers so it can become even harder to discover. True, the fact that applications that are tested and working on non-retina suddenly break on retina will cause confusing behavior even for applications written from scratch with Qt 5. Assuming we have as a goal that applications should work in high-dpi mode without any testing or modifications being needed. Morten, is that the case? The original proposal doesn't really have these problems though. We already set the render hint NonCosmeticPenByDefault on GraphicsView to avoid inconsistent scalability issues there and keep style code working when being scaled. That's why I figured that setting it for high-dpi would make sense as well, but at least in the QGraphicsView case you wouldn't get any surprises since it's always set. Having a potentially breaking behavior depend on whether high-dpi is enabled or not might not be a good idea after all... I think we should extend this behavior to QPainter in general by only initialising QPen to 1 instead of 0. We keeping the explicit 0-pen working as before. In addition, we introduce a CosmeticPenByDefault render hint that Qwt can set on its painter to make all pens cosmetic by default. (not just 0-pen) Though the Qt4PainterRenderHint could still explicitly give only 0 pen cosmetic properties. I'm not sure Qwt actually _wants_ all pens to be cosmetic by default. For 0 width pens it must already have had explicit calls to setCosmetic(true), so it's really only the default-constructed QPens that would be an issue. So I don't see how CosmeticPenByDefault would be needed in addition to Qt4CompatiblePainting. -- Samuel ___ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development
