Automatically insert draw layers for children of LazyColumn/LazyRow [170296989]

Fixed

Feature Request

Status Update

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Description

an...@google.com

created issue #1

Oct 7, 2020 01:57PM

Use case 1

LazyColumnFor(items) {
Text("$it", Modifier.background(Color.Red))
}

We scroll such list few pixels(no new items composed as a result)

Draw performance is: 124397 ns

Now we add a layer

LazyColumnFor(items) {
Text("$it", Modifier.drawLayer().background(Color.Red))
}

Draw performance is: 63371 ns (50% less)

Use case 2

LazyColumnFor(items) {
var color by remember { mutableStateOf(Color.Red) }
Text("$it", Modifier.clickable(indication = null) {
color = Color.Green
}.drawBehind {
drawRect(color)
})
}

Invalidating only one item:

Without layers on each item: 1137259 ns

With layers: 113771 ns (90% less).

We should have a way for a layouts to insert layers for children

Comments

ap...@google.com <ap...@google.com> #2Nov 23, 2020 05:11PM

The horizontal analogue of LazyVerticalGrid

ap...@google.com <ap...@google.com> #3Nov 24, 2020 10:10PM

Marked as fixed.

Project: platform/frameworks/support
Branch: androidx-main

commit 0d76cb8cdde123c08a05390a01a6a3d9d599c270
Author: Mihai Popa <popam@google.com>
Date: Tue Feb 22 13:56:58 2022

Add LazyHorizontalGrid

Relnote: "LazyHorizontalGrid was added."
Fixes: 191238807
Test: new tests in lazy.grid
Change-Id: I61ae7abe269fdb3776c301dd5c233762f9766f4d

M compose/foundation/foundation/src/androidAndroidTest/kotlin/androidx/compose/foundation/lazy/grid/LazyGridAnimateItemPlacementTest.kt
M compose/foundation/foundation/api/public_plus_experimental_current.txt
M compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/lazy/LazyGrid.kt
M compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/lazy/grid/LazyGridItemPlacementAnimator.kt
M compose/foundation/foundation/samples/src/main/java/androidx/compose/foundation/samples/LazyGridSamples.kt
M compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/lazy/grid/LazyMeasuredItem.kt
M compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/lazy/grid/LazyGrid.kt
M compose/foundation/foundation/src/androidAndroidTest/kotlin/androidx/compose/foundation/lazy/grid/LazyArrangementsTest.kt
M compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/lazy/grid/LazyMeasuredLine.kt

https://android-review.googlesource.com/1994930

Issue 170296989

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Comments

ap...@google.com <ap...@google.com> #2Nov 23, 2020 05:11PM

ap...@google.com <ap...@google.com> #3Nov 24, 2020 10:10PM

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