[Feature Request] Allow compose components to inherit their parent's 'absolute elevation' [171031040]

Fixed

Feature Request

Status Update

No update yet.

Description

al...@gmail.com

created issue #1

Oct 16, 2020 04:49PM

In material-components-android, views automatically inherit the elevation of their parent ViewGroups using this utility method: https://github.com/material-components/material-components-android/blob/89a1bf883fa614702bb43d2cfa75a38005a42421/lib/java/com/google/android/material/internal/ViewUtils.java#L259-L271

For example, say you have a MaterialButton (with 4dp elevation) contained inside of a BottomSheet (with 16dp elevation). In dark theme, the MaterialButton will inherit the BottomSheet's elevation, meaning that its elevation overlay will render as if the MaterialButton had 20dp elevation instead of 4dp elevation.

It would be useful if there was a builtin mechanism to support this in Compose. This would make it easier to migrate UIs written with material-components-android to Compose while still maintaining UI consistency.

Comments

al...@gmail.com <al...@gmail.com> #2Oct 18, 2020 10:10PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit c60f33e229e31ab328ef6b59dab63b264954831c
Author: Alexandre Elias <aelias@google.com>
Date: Fri Jul 10 16:23:09 2020

Semantics no-op cleanups

Partly in response to lmr's broad code review, I did a pass of
superficial API/implementation cleanup. The main changes are:

- I changed each Boolean SemanticsProperty where false is equivalent to
not being present to take "Unit" instead. This is conceptually
clearer: it avoids questions like "can I cancel out a semantics from a
merged child by setting it to false?" Because "property = Unit" looks
weird, I also changed the style of these to "property()".

- I moved the Semantics id generator closer to where it's used, in
SemanticsModifierCore. I made it internal and an AtomicInt.
(Note that integer ids are heavily used in the Android
AccessibilityNodeInfo APIs so I can't simply remove them entirely.)

- I deleted dead code. Some examples include SemanticsHintOverrides,
a public API not connected to anything, and SemanticsPropertyKey
merge() open method which is never called. (In both cases I have
a different plan in mind for accessibility.)

Fixes: 145951226
Fixes: 145955412
Test: existing tests
Relnote: "Single-value semantics properties now use a calling style.
For example, 'semantics { hidden = true }' is now written as:
'semantics { hidden() }'."

Change-Id: Ic1afd12ea22c926babc9662f1804d80b33aa0cfc

M ui/integration-tests/benchmark/src/androidTest/java/androidx/ui/benchmark/test/LayoutNodeModifierBenchmark.kt
M ui/ui-core/api/0.1.0-dev15.txt
M ui/ui-core/api/current.txt
M ui/ui-core/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-core/api/public_plus_experimental_current.txt
M ui/ui-core/api/restricted_0.1.0-dev15.txt
M ui/ui-core/api/restricted_current.txt
M ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/graphics/vector/VectorTest.kt
M ui/ui-core/src/androidAndroidTest/kotlin/androidx/ui/semantics/SemanticsTests.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidActuals.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeView.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidComposeViewAccessibilityDelegateCompat.kt
M ui/ui-core/src/androidMain/kotlin/androidx/ui/core/AndroidPopup.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/Expect.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsConfiguration.kt
D ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsHintOverrides.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsModifier.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsNode.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsOwner.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/core/semantics/SemanticsWrapper.kt
M ui/ui-core/src/commonMain/kotlin/androidx/ui/semantics/SemanticsProperties.kt
M ui/ui-foundation/api/0.1.0-dev15.txt
M ui/ui-foundation/api/current.txt
M ui/ui-foundation/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-foundation/api/public_plus_experimental_current.txt
M ui/ui-foundation/api/restricted_0.1.0-dev15.txt
M ui/ui-foundation/api/restricted_current.txt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Selectable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt
M ui/ui-foundation/src/main/java/androidx/ui/foundation/semantics/FoundationSemanticsProperties.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ButtonTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/CardTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/CheckboxScreenshotTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/RadioButtonScreenshotTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ScaffoldTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/SnackbarTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/SurfaceTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/ripple/RippleIndicationTest.kt
M ui/ui-material/src/androidTest/java/androidx/ui/material/textfield/TextFieldScreenshotTest.kt
M ui/ui-material/src/main/java/androidx/ui/material/AppBar.kt
M ui/ui-material/src/main/java/androidx/ui/material/TextFieldImpl.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/AssertsTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/CallSemanticsActionTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/ErrorMessagesTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/FindersTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/PrintToStringTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/ScrollToTest.kt
M ui/ui-test/src/androidTest/java/androidx/ui/test/TextActionsTest.kt
M ui/ui-test/src/main/java/androidx/ui/test/Actions.kt
M ui/ui-test/src/main/java/androidx/ui/test/Filters.kt
M ui/ui-text/api/0.1.0-dev15.txt
M ui/ui-text/api/current.txt
M ui/ui-text/api/public_plus_experimental_0.1.0-dev15.txt
M ui/ui-text/api/public_plus_experimental_current.txt
M ui/ui-text/api/restricted_0.1.0-dev15.txt
M ui/ui-text/api/restricted_current.txt
M ui/ui-text/src/commonMain/kotlin/androidx/ui/text/CoreTextField.kt
M ui/ui-text/src/commonMain/kotlin/androidx/ui/text/TextSemanticsProperties.kt

https://android-review.googlesource.com/1360099

cl...@google.com <cl...@google.com> Oct 19, 2020 10:31AM

Reassigned to an...@google.com.

an...@google.com <an...@google.com> Oct 19, 2020 11:35AM

Reassigned to lp...@google.com.

lp...@google.com <lp...@google.com> #3Oct 19, 2020 02:04PM

Yep, your implementation seems reasonable / how we would implement this. There are some questions around whether this behavior is easy to understand / expected, but at least for the migration case it seems reasonable to support in some capacity.

al...@gmail.com <al...@gmail.com> #4Oct 19, 2020 05:26PM

I'll leave it up to your team to decide, but IMO (regardless of whether the behavior is easy to understand/expected), this behavior definitely has its benefits. One example where we depend on it in our own app is when placing surface-background-colored components on top of bottom-sheets. Without the concept of absolute elevation, those components end up looking like dark punch-out holes against a much brighter bottom sheet background in dark mode.

Just wanted to share my experience. :)

Message last modified on Oct 19, 2020 06:03PM

ch...@google.com <ch...@google.com> #5Oct 19, 2020 05:39PM

Thanks to Louis for pointing me towards AmbientElevationOverlay and ElevationProvider as a way to make this a bit easier to implement. https://github.com/chrisbanes/tivi/pull/716

ap...@google.com <ap...@google.com> #6Oct 29, 2020 01:36PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit a632fa2b38d798a4350214875b4e3695ebc0d0b6
Author: Louis Pullen-Freilich <lpf@google.com>
Date: Thu Oct 22 16:44:07 2020

Adds AmbientAbsoluteElevation to represent the sum of elevation provided by Surfaces. Also changes Surface to use this absolute elevation when calculating elevation overlays, to represent the total elevation at that point in the hierarchy, and not the elevation of the nearest Surface.

Bug:

b/171031040

Test: ElevationOverlayTest, SurfaceTest
Relnote: "Surface now uses the absolute (total) elevation when calculating elevation overlays, so a Surface nested in another Surface will use the combined elevation to draw the overlay."
Change-Id: I7bd2b08da276d5624baad6a2e59eb74bc021bc45

M compose/material/material/api/current.txt
M compose/material/material/api/public_plus_experimental_current.txt
M compose/material/material/api/restricted_current.txt
A compose/material/material/samples/src/main/java/androidx/compose/material/samples/ElevationSamples.kt
M compose/material/material/src/androidAndroidTest/kotlin/androidx/compose/material/ElevationOverlayTest.kt
M compose/material/material/src/androidAndroidTest/kotlin/androidx/compose/material/SurfaceTest.kt
M compose/material/material/src/commonMain/kotlin/androidx/compose/material/Elevation.kt
M compose/material/material/src/commonMain/kotlin/androidx/compose/material/Surface.kt

https://android-review.googlesource.com/1470849

lp...@google.com <lp...@google.com> Oct 29, 2020 01:46PM

Marked as fixed.

al...@gmail.com <al...@gmail.com> #7Oct 29, 2020 02:57PM

Woot thanks Louis!