Partial-screen magnification, introduced in Android 12 gives low-vision users improved viewing options.
Low-vision users might wear prescription eyeglasses, or they might have temporary difficulty interpreting a display due to environmental conditions or illness. Temporary difficulties can be caused by things like excessive lighting or extreme user fatigue.
The partial-screen magnification feature in Android 12 lets a user switch between full-screen magnification and partial-screen magnification. With partial-screen magnification, Users can drag the magnified partial screen around the display to view different areas. A switch button that lets the user toggle to a full-screen magnification appears when magnification is activated.
Figure 1. Switch button for toggling between views
The switch button fades out of view after five seconds of inactivity, and reappears when the user interacts with the screen again. Users can extend this duration by changing the Accessibility timeout value in Settings.
Users select their preferences under Magnifications in Settings. They can stay with the regular zoom functionality, and they can toggle between the zoom and magnify functions as needed by selecting Switch between full and partial screen under Choose how to magnify. (See Figure 2.)
Figure 2. Magnification options in Settings
Users have the option to switch between both by default, or they can select the Magnify full screen option. Android 11 devices that are upgraded to Android 12 have the partial-screen magnification function. A user with an Android 11 device that has been upgraded to Android 12 can also switch between both, but that's not a default option.
The magnification change is animated, as shown in Figure 3. The scale either increases or decreases gradually until the specified target value is reached.
Figure 3. Animation with magnification
OEMs and partners don’t need to do anything to implement the partial-screen
magnification feature in Android 12. It’s on by
default. To disable it, set the boolean
config_magnification_area value to
false in the config.xml
file, which removes it from Settings. When it’s enabled, Users
can turn it off in Settings, but they can't remove it. (When a user turns
the partial-screen magnification off in Settings, the
config_magnification_area setting original value of
Android 11 and lower partial screen magnification
Android 11 and lower devices that are upgraded to Android 12 can use this feature. Users with Android 11 (or lower) devices who originally used the full magnification function upgrade to Android 12 turn on full magnification for the first time, a notification dialog appears to remind them that they can magnify part of their screen.
If they’ve never used full magnification they can go to Settings > Accessibility > Magnification to use both full and partial-screen magnification.
Triple-tap and accessibility
When Users select partial-screen magnification by using a triple-tap movement, a warning pop-up dialog box appears that prompts them to Switch to accessibility button instead. They can select Use triple-tap, but the dialog pop-up ensures that anyone who wants more accessibility in the UI knows that it’s available. The accessibility button assists users who have hand tremors or any reasons that a triple-tap mechanism wouldn’t be useful for them.
Figure 4. Accessibility button dialog