Hi, I'm playing around with runtime rendering effe...

# compose

[Sergey Y.]

Hi, I'm playing around with runtime rendering effects and I'm confused.
Is it possible to apply a rendering effect to only part of a Composable widget, but not the whole thing?
For example, how to blur the content behind widget which is ontop of the screen content (not a dialog, just a regular composable stacked on another.) within its bounds. To limit the area of the effect.
I tried combinations of graphics layers, drawWithContent and clipRects, but it didn't give the desired result.
Also tried using RenderNode directly as described in Chet's post.
Haven't found a way to combine it with the Compose UI drawing system yet.
🧵

[Sergey Y.]

Screenshot_20230201_024240.png

[Sergey Y.]

the rendering effect applies only to all background content.

[Sergey Y.]

Only one idea comes to mind.
Create a duplicate layout in the widget hierarchy that will be blurred.
Then crop it with a surface content mask.
But this is extremely inefficient and I don't want to do it that way.

[Sergey Y.]

I wish we could have possibility to set rendering effects within drawContent modifiers. (I don't know if it is possible)
E.g. pseudo code:

Modifier.drawWithContent {
    drawContent() // draws original content
    clipPath(path) { // draws the part of the content covered by the mask and applies the given effect to it
        renderEffect = RenderEffect.createBlurEffect(...)
        drawContent()
    }
}

[Sergey Y.]

this is starting to remind me of the render pass architecture in 2D/3D graphic renderers 🫠