Animation resume/pause support

[chonwhite]

I'm using Image rotation animation to emulate a vinyl spin, and need to pause and resume the animation based on some state change. Can't find any documentation mentioning animation pause and resume. My main language is C++, BTW.

[ogoffart]

Thanks for your issue. (I moved it into discussion to keep the issues for bug tracking)

The way to do permanently running animation is to use the animation-tick() builtin function.
Depending on the state, you can use it to make the angle vary, or not.
Example

[chonwhite]

Thanks, works like a charm!

[chonwhite]

A small issue though, when the animation is applied, it consumes quite a bit of CPU, about 15% on my M2 MacBook Pro， maybe could be optimised later?

[ogoffart]

Are you building in release mode?
And what renderer are you using? the default is femtovg, but you can try the skia renderer, it might be faster

[chonwhite]

Building under Release mode, the whole project was based on slint-cpp-template, and no changes were made to project settings.

[chonwhite]

Replicated the same animation with Objective-C on MacOSX and here's the performance result.

[tronical]

I think we're missing frame throttling on macOS (as well as others). The issue is particularly visible on macOS - it also causes delays with accessibility updates. Winit now has support for this on Wayland. I've filed #4025 for our side.