AspectRatioStrategy

const val FALLBACK_RULE_AUTO = 1: Int

CameraX automatically chooses the next best aspect ratio which contains the closest field of view (FOV) of the camera sensor, from the remaining options.

const val FALLBACK_RULE_NONE = 0: Int

CameraX doesn't fall back to select sizes of any other aspect ratio when this fallback rule is used.

Note that an AspectRatioStrategy with more restricted settings may result in that no resolution can be selected to use. Applications will receive IllegalArgumentException when binding the UseCases with such kind of AspectRatioStrategy.

const val RATIO_16_9_FALLBACK_AUTO_STRATEGY: AspectRatioStrategy

The pre-defined aspect ratio strategy that selects sizes with RATIO_16_9 in priority. Then, selects sizes with other aspect ratios according to which aspect ratio can contain the closest FOV of the camera sensor.

Please see the Output streams, Cropping, and Zoom introduction to know more about the camera FOV.

const val RATIO_4_3_FALLBACK_AUTO_STRATEGY: AspectRatioStrategy

The pre-defined default aspect ratio strategy that selects sizes with RATIO_4_3 in priority. Then, selects sizes with other aspect ratios according to which aspect ratio can contain the closest FOV of the camera sensor.

Please see the Output streams, Cropping, and Zoom introduction to know more about the camera FOV.

AspectRatioStrategy(preferredAspectRatio: Int, fallbackRule: Int)

Creates a new AspectRatioStrategy instance, configured with the specified preferred aspect ratio and fallback rule.

OEMs might make the width or height of the supported output sizes be mod 16 aligned for performance reasons. This means that the device might support 1920x1088 instead of 1920x1080, even though a 16:9 aspect ratio size is 1920x1080. CameraX can select these mod 16 aligned sizes when applications specify the preferred aspect ratio as RATIO_16_9.

Some devices may have issues using sizes of the preferred aspect ratios. CameraX recommends that applications use the FALLBACK_RULE_AUTO setting to avoid no resolution being available, as an IllegalArgumentException may be thrown when calling bindToLifecycle to bind UseCases with the AspectRatioStrategy specified in the ResolutionSelector.

fun getFallbackRule(): Int

Returns the specified fallback rule for choosing the aspect ratio when the preferred aspect ratio is not available.

fun getPreferredAspectRatio(): Int

Returns the specified preferred aspect ratio.