
Vpaint function of a conjecture (the future may be realized)
That would be nice to have both a light theme and a dark theme! Though, allowing this would require some work, and maybe redesign of the icons to make them work with both themes. I probably won't implement this soon, but I'll keep it in mind.
Having a silder would be even more complicated!

Mr. Boris, under the MIT license agreement, is there a similar effect of the OpenCV Visual Special Effects Library similar to the BSD protocol? Or a gegl effect library similar to the GPL agreement if the BSD is compatible with the MIT license. Does it mean that OpenCV can be integrated inside vpaint as a special effects tool set?
BSD and MIT are compatible, therefore VPaint could use OpenCV, as far as licensing is concerned. However, OpenCV works with raster graphics, not vector graphics, therefore it doesn't make sense to use OpenCV in VPaint. You could always do these kind of effects as a post-processing step once you've exported the animation as a rasterized video, for instance in after effects, etc.
Hi 爪哇程序猿 !
Are you talking about motion blur (= blur due to the motion of objects, like when taking a picture with long exposure, https://en.wikipedia.org/wiki/Motion_blur) ? Unfortunately, I think that would be hard to implement with the current rendering method. But it is definitely a very good suggestion !! It's interesting, because motion blur is always used in 3D animation, but it doesn't seem used a lot in 2D animation.
Are you talking about motion blur (= blur due to the motion of objects, like when taking a picture with long exposure, https://en.wikipedia.org/wiki/Motion_blur) ? Unfortunately, I think that would be hard to implement with the current rendering method. But it is definitely a very good suggestion !! It's interesting, because motion blur is always used in 3D animation, but it doesn't seem used a lot in 2D animation.
Vpaint requires a pixel brush for creating sketches and line drafts on the canvas (which supports alpha transparency), which is used to design the styling, which does not interfere with the editing of vector graphics. The benefit of doing this is when there is an intuitive sketch without having to use Too many vector lines! Of course it can also convert bitmap lines to vector edges. Of course the sketch drawn by the pixel brush can choose not to render in the final work.Of course, the pixel brush can also be just an option for the vector brush. 

Similar to this sketch tool! http://www.youtube.com/watch?v=ApxIvBjtlPw
Thanks for the suggestion! Instead of a pixel "brush", what you're suggesting is more to have pixel "layers", like in Pencil2D: http://www.pencil2d.org/tutorials/. Of course, layers can be hidden for the final render.
But in fact, I don't think they are necessary
The same functionality can be achieved with vector layers: one can just create two vector layers, one called "draft" and another called "ink". In the draft layer, you can use thousands and thousands of small vector strokes (with auto-snap and auto-intersect disabled), while in the ink layer, you would use long, clean strokes, with auto-snap enabled (and possibly also auto-intersect). The reason users usually prefer to use pixels for drafting is simply that vector tools are just not good-enough in many applications. But with I'm confident I can make vector tools adapted for drafting too. Currently, one important missing tool is an "eraser", which is a bit more complicated to implement for vector strokes than pixel strokes, but not impossible.
Each layer can remember its own brush settings, so that when you draw on the draft layer, you always have auto-snap and auto-intersect disabled, and when you draw on the ink layer, you always have auto-snap enabled.
But in fact, I don't think they are necessary

Each layer can remember its own brush settings, so that when you draw on the draft layer, you always have auto-snap and auto-intersect disabled, and when you draw on the ink layer, you always have auto-snap enabled.
Hi! Mr Boris!Hope vpaint future versions have animated warehouses (animated loops). Used to save the selected animation content for some time periods. Save animation for a certain period of time, such as the turn of head that often appear in animation. The copied animations that are called from the animated warehouse can be changed without affecting the original animation.This function is more like a time loop, but it is not associated with the original animation. More like a animation copy.Calls the animation content of a certain time period to a point in time of the timeline 
