Is this `Parallel Rendering Mode` the same concept...

# compose

[Sergey Y.]

Is this Parallel Rendering Mode the same concept as Android’s RenderThread?
Also, if this mode primarily involves offloading to a single dedicated thread for dispatching render commands (similar to how RenderThread conceptually works), isn’t calling it Parallel Rendering Mode potentially a bit confusing? The parallel often suggests multiple threads might be involved in the actual drawing execution, not just a single dispatch thread.
I’d appreciate any clarifications. 😄

(source of the photo)

[yschimke]

Is this an iOS UIKit thing?

[Sergey Y.]

This isn’t unique to UIKit. Many modern UI toolkits have a dedicated main thread and a separate renderer thread for dispatching GPU commands. It seems like Compose Multiplatform is following a similar model, at least on iOS, maybe even on desktop, though I’m not sure. I haven’t watched the KotlinConf livestream yet.

[yschimke]

Sure, but I meant this specific flag

[Sergey Y.]

Not sure I follow

[Dumitru Preguza]

Interesting if it’s by default enabled, or are there any trade offs

[romainguy]

Parallel doesn't imply more than 2 threads

[Sergey Y.]

In such systems, does the main thread count as the rendering thread as well?
Technically, rendering is offloaded to the second thread. Is the main thread considered the recorder thread, or is there a better term for it? Or am I mistaken?

[romainguy]

I'm not sure what you're looking for. This might just mean rendering happens in parallel to whatever the main thread is doing.

[romainguy]

Fwiw on Android the renderer did used to use multiple threads in spsicifc cases. Don't know if Skia does that but the full hwui implementation did to prepare paths

[Sergey Y.]

Here it is github.com/JetBrains/compose-multiplatform-core/blob/a476deb771f9810965c934b0bb286c52576dcdd2/compose/ui/ui/src/uikitMain/kotlin/androidx/compose/ui/window/MetalRedrawer.uikit.kt#L454