> > This graph concept might be a good usecase for a more complex example down > > the line though.. I'll keep it in mind and maybe it will be included in Qt > > in the future :) > > Oh... that sucks.
I think so too, so I spent some time yesterday evening to put it together: https://codereview.qt-project.org/#change,58589 It does the background, grid, line and dropshadow as 4 separate geometry nodes and shows several new sides of the scene graph API. The line stroking is a bit crude as it doesn't account for the line angle so steep slopes will come out thinner, but it should be a good starting point. cheers, Gunnar > Well, i guess i'm just gonna have to play with this > and see how it turns out. If (assuming i can figure it out) i get it > working i will certainly share my code in here or on this list. > >> >>> - for the dropshadow, do exactly the same as for the line, except you can >>> use the custom vertex shader to expand it a little bit more and change the >>> opacity to make it a more blurry. >> Here i really do wonder if it isn't easier to just make a simple line >> component and use QtGraphicalEffects for the shadowing... I guess >> experimenting with both will tell which option works best. >> >> >>> - for the gradient under the line, create a trianglestrip and colorize it >>> according based on the y position in the fragment shader. >> Yeah, figured it would be something like that. Will do. >>> >>>> >>>> 2. Another way i see is taking the OpenGL direct approach following >>>> the "OpenGLunderQML example [1]. I can probably work of that example, >>>> but i really try to stay away from doing direct opengl interaction.. >>> >>> Raw OpenGL has its benefits, which is why the example and the feature is >>> there, but I've been thinking that the primary usecase for OpenGLUnderQML >>> is when you have a game/cad app running and QML is just the HUD controls. >>> Using raw opengl for UI elements has the downside that you don't get any >>> inherited clipping, transformation, nor opacity so things might be quite a >>> bit more complicated to manage inside your UI. >> Exactly my opinion as well. I try to stay away from raw opengl calls. >>> >>>> >>>> 3. A third possible way that i can think of is by throwing everything >>>> out and starting over in a very abstract manner. Making a bunch of >>>> small components (in C++) like: >>>> (note: this is still for the charting stuff [0]) >>>> - 1 component to draw the background with a little more power then a >>>> Rectangle. However, if i choose this route i might as well use the >>>> QtGraphicalEffects for the added power (gradients) since that provides >>>> it. >>>> - 1 component for drawing a grid on top of the gradient. >>>> - 1 component for drawing a line where i probably only provide the >>>> data indicating where the line should be. Again i can use >>>> QtGraphicalEffects on top of this to add additional shadow. However, i >>>> find the default OpenGL line drawing stuff (even with multisampling) >>>> of a very very very poor rendering quality. I'm really thinking of >>>> using the "vase renderer" for drawing a way sharper line [2] Another >>>> note, this might also be very interesting for you to draw way sharper >>>> "scene graph fonts" which at the moment still look quite blurry at >>>> it's best under desktop environments. >>> >>> The distancefield fonts are unhinted and this is why they look more blurry >>> than native fonts (at least on windows and potentially linux). You can >>> enable native rendering by sacrificing font scalability: >>> http://blog.qt.digia.com/blog/2012/08/08/native-looking-text-in-qml-2/ >>> >>>> - I'm stuck at how to animate the line as more data flows in.. >>>> >>>> I hope you can advice me here in picking an option to go for. It's all >>>> quite a bit of work and all likely has the same end result. Right now >>>> i'm leaning towards option 3 where i was trying to go for option 1 >>>> till this very moment. >>>> >>>> >>>> [0] http://i.stack.imgur.com/Zk2RG.png -- i try to make it look as >>>> crisp as this one >>> >>> >>>> [1] >>>> https://qt.gitorious.org/qt/qtdeclarative/trees/stable/examples/quick/scenegraph/openglunderqml >>>> [2] >>>> http://www.codeproject.com/Articles/226569/Drawing-polylines-by-tessellation >>>> >>>> >>>> On Mon, Jun 10, 2013 at 10:07 AM, Sletta Gunnar <gunnar.sle...@digia.com> >>>> wrote: >>>>> >>>>> On Jun 8, 2013, at 11:33 PM, Mark <mark...@gmail.com> wrote: >>>>> >>>>>> Hi, >>>>>> >>>>>> Back when the graphical effects where first showcased in a blog i was >>>>>> already kinda scared that there would be no C++ interface to use them >>>>>> from the C++ side. Now i find myself in the position where i want to >>>>>> use the DropShadow element from that very same module in custom QML >>>>>> Scene Graph module and give a line a shadow. >>>>>> >>>>>> I kinda - very much - dislike copying the relavant parts of the >>>>>> DropShadow code and re-create that in C++.. >>>>>> >>>>>> Is there a way that i can use DropShadow from the C++ side? >>>>> >>>>> There is no way to do this using pure C++ API. You could construct it >>>>> from c++ using QQmlComponent and set the source property by passing it >>>>> the item that creates the geometry node. >>>>> >>>>> cheers, >>>>> Gunnar >>>>> >>>>>> >>>>>> Regards, >>>>>> Mark >>>>>> _______________________________________________ >>>>>> Interest mailing list >>>>>> Interest@qt-project.org >>>>>> http://lists.qt-project.org/mailman/listinfo/interest >>>>> >>> > _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
