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Search Central Live Tokyo: The 2025 Return



Get ready, Japan! We're thrilled to announce the return of Search Central Live Tokyo on Nov 7,
2025! If you are fluent in Japanese and are interested, read on! We're bringing
back all the elements you loved, with even mo...
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Google
12 Sep 2025

Think Week 2025

At Think Retail 2025, we shared our next-gen AI-powered solutions to help retailers connect with their customers.
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Google
10 Sep 2025

HDR and User Interfaces




Posted by Alec Mouri - Software Engineer






As explained in What is HDR?, we can think of HDR as only referring to a luminance range brighter than SDR. When integrating HDR content into a user interface, you must be careful when your user interface is primarily SDR colors and assets. The human visual system adapts to perceived color based on the surrounding environment, which can lead to surprising results. We’ll look at one pertinent example.

Simultaneous Contrast

Consider the following image:

Source: Wikipedia


This image shows two gray rectangles with different background colors. For most people viewing this image, the two gray rectangles appear to be different shades of gray: the topmost rectangle with a darker background appears to be a lighter shade than the bottommost rectangle with a lighter background.

But these are the same shades of gray! You can prove this to yourself by using your favorite color picking tool or by looking at the below image:




This illustrates a visual phenomenon called simultaneous contrast. Readers who are interested in the biological explanation may learn more here.

Nearby differences in color are therefore “emphasized”: colors appear darker when immediately next to brighter colors. That same color would appear lighter when immediately next to darker colors.

Implications on Mixing HDR and SDR

The effect of simultaneous contrast affects the appearance of user interfaces that need to present a mixture of HDR and SDR content. The peak luminance allowed by HDR will create an effect of simultaneous contrast: the eye will adapt* to a higher peak luminance (and oftentimes a higher average luminance in practice), which will perceptually cause SDR content to appear dimmer although technically the SDR content luminance has not changed at all. For users, this can be expressed as: my phone screen became “grey” or “washed out”.

We can see this phenomenon in the below image. The device on the right simulates how photos may appear with an SDR UI, if those photos were rendered as HDR. Note that the August photos look identical when compared side-by-side, but the quality of the SDR UI is visually degraded.




Applications, when designing for HDR, need to consider how “much” SDR is shown at any given time in their screens when controlling how bright HDR is “allowed” to be. A UI that is dominated by SDR, such as a gallery view where small amounts of HDR content are displayed, can suddenly appear to be darker than expected.

When building your UI, consider the impact of HDR on text legibility or the appearance of nearby SDR assets, and use the appropriate APIs provided by your platform to constrain HDR brightness, or even disable HDR. For example, a 2x headroom for HDR brightness may be acceptable to balance the quality of your HDR scene with your SDR elements. In contrast, a UI that is dominated by HDR, such as full-screen video without other UI elements on-top, does not need to consider this as strongly, as the focus of the UI is on the HDR content itself. In those situations, a 5x headroom (or higher, depending on content metadata such as UltraHDR's max_content_boost) may be more appropriate.

It might be tempting to “brighten” SDR content instead. Resist this temptation! This will cause your application to be too bright, especially if there are other applications or system UI elements on-screen.

How to control HDR headroom

Android 15 introduced a control for desired HDR headroom. You can have your application request that the system uses a particular HDR headroom based on the context around your desired UI:

If you only want to show SDR content, simply request no headroom.
If you only want to show HDR content, then request a high HDR headroom up to and according to the demands of the content.
If you want to show a mixture of HDR and SDR content, then can request an intermediate headroom value accordingly. Typical headroom amounts would be around 2x for a mixed scene and 5-8x for a fully-HDR scene.


Here is some example usage:

// Required for the window to respect the desired HDR headroom.
// Note that the equivalent api on SurfaceView does NOT require
// COLOR_MODE_HDR to constraint headroom, if there is HDR content displayed
// on the SurfaceView.
window.colorMode = ActivityInfo.COLOR_MODE_HDR
// Illustrative values: different headroom values may be used depending on
// the desired headroom of the content AND particularities of apps's UI
// design.
window.desiredHdrHeadroom =
if(/* SDR only */) {
0f
} else {
if (/* Mixed, mostly SDR */) {
1.5f
} else {
if ( /* Mixed, mostly HDR */) {
3f
} else {
/* HDR only */
5f
}
}
}


Other platforms also have APIs that allow for developers to have some control over constraining HDR content in their application.

Web platforms have a more coarse concept: The First Public Working Draft of the CSS Color HDR Module adds a constrained-high option to constrain the headroom for mixed HDR and SDR scenes. Within the Apple ecosystem, constrainedHigh is similarly coarse, reckoning with the challenges of displaying mixed HDR and SDR scenes on consumer displays.

If you are a developer who is considering supporting HDR, be thoughtful about how HDR interacts with your UI and use HDR headroom controls appropriately.



*There are other mechanisms the eye employs for light adaptation, like pupillary light reflex, which amplifies this visual phenomenon (brighter peak HDR light means the pupil constricts, which causes less light to hit the retina).
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Google
10 Sep 2025

Use Gemini to refine text in Slides

What’s changing You can now refine text within a text box in Google Slides using Gemini. In just a few clicks, you can ask Gemini to help rephrase, shorten, formalize, or bulletize the current text using pre-set options optimized for Slides. Alter...
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Google
5 Sep 2025

How Dashlane Brought Credential Manager to Wear OS with Only 78 New Lines of Code




Posted by John Zoeller - Developer Relations Engineer, Loyrn Hairston - Product Marketing Manager, and Jonathan Salamon - Dashlane Staff Software Engineer







Dashlane is a password management and provision tool that provides a secure way to manage user credentials, access control, and authentication across multiple systems and applications.

Dashlane has over 18 million users and 20,000 businesses in 180 countries. It’s available on Android, Wear OS, iOS, macOS, Windows, and as a web app with an extension for Chrome, Firefox, Edge, and Safari.

Recently, they expanded their offerings by creating a Wear OS app with a Credential Provider integration from the Credential Manager API, bringing passkeys to their clients and users on smartwatches.

Streamlining Authentication on Wear OS

Dashlane users have frequently requested a Wear OS solution that provides standalone authentication for their favorite apps. In the past, Wear OS lacked the key APIs necessary for this request, which kept Dashlane from being able to provide the functionality. In their words:

“Our biggest challenge was the lack of a standard credentials API on Wear OS, which meant that it was impossible to bring our core features to this platform.”

This has changed with the introduction of the new Credential Manager API on Wear OS.

Credential Manager provides a simplified, standardized user sign-in experience with built-in authentication options for passkeys, passwords, and federated identities like Sign in with Google. Conveniently, it can be implemented with minimal effort by reusing the same code as the mobile version.

The Dashlane team was thrilled to learn about this, as it meant they could save a lot of time and effort: “[The] CredentialManager API provides the same API on phones and Wear OS; you write the code only once to support multiple form factors.”

Selecting Dashlane-provided credentials is simple for users


After Dashlane had planned out their roadmap, they were able execute their vision for the new app with only a small engineering investment, reusing 92% of the Credential Manager code from their mobile app. And because the developers built Dashlane’s app UI with Jetpack Compose for Wear OS, 60% of their UI code was also reused.




Developing for Wear OS

To provide credentials to other apps with Credential Manager, Dashlane needed to implement the Credential Provider interface on Wear OS. This proved to be a simple exercise in calling their existing mobile code, where Dashlane had already implemented behavior for credential querying and credential selection.

For example, Dashlane was able to reuse their logic to handle client invocations of CredentialManager.getCredential. When a client invokes this, the Android framework propagates the client’s getCredentialRequest to Dashlane’s CredentialProviderService.onBeginGetCredentialRequest implementation to retrieve the credentials specified in the request.

Dashlane delegates the logic for onBeginGetCredentialRequest to their handleGetCredentials function, below, which is shared between their mobile and Wear OS implementations.

// When a Credential Manager client calls 'getCredential', the Android
// framework invokes `onBeginGetCredentialRequest`. Dashlane
// implemented this `handleGetCredentials` function to handle some of
// the logic needed for `onBeginGetCredentialRequest`
override fun handleGetCredentials(
context: Context,
request: BeginGetCredentialRequest):
List<CredentialEntry> =
request.beginGetCredentialOptions.flatMap { option ->
when (option) {
// Handle passkey credential
is BeginGetPublicKeyCredentialOption -> {
val passkeyRequestOptions = Gson().fromJson(
option.requestJson, PasskeyRequestOptions::class.java)

credentialLoader.loadPasskeyCredentials(
passkeyRequestOptions.rpId,
passkeyRequestOptions.allowCredentials ?: listOf()
).map { passkey ->
val passkeyDisplayName = getSuggestionTitle(passkey, context)

PublicKeyCredentialEntry.Builder(
context,
passkeyDisplayName,
pendingIntentForGet(context, passkey.id),
option
)
.setLastUsedTime(passkey.locallyViewedDate)
.setIcon(buildMicroLogomarkIcon(context = context))
.setDisplayName(passkeyDisplayName)
.build()
// Handle other credential types


Reusing precise logic flows like this made it a breeze for Dashlane to implement their Wear OS app.

“The Credential Manager API is unified across phones and Wear OS, which was a huge advantage. It meant we only had to write our code once.”

Impact and Improved Growth

The team is excited to be among the first credential providers on wearables: “Being one of the first on Wear OS was a key differentiator for us. It reinforces our brand as an innovator, focusing on the user experience, better meeting and serving our users where they are.”

As an early adopter of this new technology, Dashlanes Wear OS app has already shown early promise, as described by Dashlane software engineer, Sebastien Eggenspieler: “In the first 3 months, our Wear OS app organically grew to represent 1% of our active device install base.”

With their new experience launched, Wear OS apps can now rely on Dashlane as a trusted credential provider for their own Credential Manager integrations, using Dashlane to allow users to log in with a single tap; and users can view details about their credentials right from their wrist.

Dashlane’s innovative design helps users manage their credentials


Dashlane’s Recommendations to Wear OS Developers

With their implementation complete, the Dashlane team can offer some advice for other developers who are considering the Credential Manager API. Their message is clear: “the future is passwordless… and passkeys are leading the way, [so] provide a passkey option.”

As a true innovator in their field, and the preferred credential provider for so many users, we are thrilled to have Dashlane support Credential Manager. They truly inspired us with their commitment to providing Wear OS users with the best experience possible:

“We hope that in the future every app developer will migrate their existing users to the Credential Manager API.”

Get Started with Credential Manager

With its elegant simplicity and built-in secure authentication methods, the Credential Manager API provides a simple, straightforward authentication experience for users that changes the game in Wear OS.

Want to find out more about how Dashlane is driving the future of end-user authentication? Check out our video blog with their team in Paris, and read about how they found a 70% in sign-in conversion rates with passkeys.

To learn more about how you can implement Credential Manager, read our official developer and UX guides, and be sure to check out our brand new blog post and video blog as part of Wear OS Spotlight week!

We’ve also expanded our existing Credential Manager sample to support Wear OS, to help guide you along the way, and if you'd like to provide credentials like Dashlane, you can use our Credential Provider sample.

Finally, explore how you can start developing additional experiences for Wear OS today with our documentation and samples.
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Google
3 Sep 2025