IAttachedSurfaceControl.BufferTransformHint Property
Definition
Important
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The transform hint can be used by a buffer producer to pre-rotate the rendering such that the final transformation in the system composer is identity.
public virtual int BufferTransformHint { [Android.Runtime.Register("getBufferTransformHint", "()I", "GetGetBufferTransformHintHandler:Android.Views.IAttachedSurfaceControl, Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null", ApiSince=32)] get; }[<get: Android.Runtime.Register("getBufferTransformHint", "()I", "GetGetBufferTransformHintHandler:Android.Views.IAttachedSurfaceControl, Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null", ApiSince=32)>]
member this.BufferTransformHint : intProperty Value
- Attributes
Remarks
The transform hint can be used by a buffer producer to pre-rotate the rendering such that the final transformation in the system composer is identity. This can be very useful when used in conjunction with the h/w composer HAL in situations where it cannot handle rotations or handle them with an additional power cost.
The transform hint should be used with ASurfaceControl APIs when submitting buffers. Example usage:
1. After a configuration change, before dequeuing a buffer, the buffer producer queries the function for the transform hint.
2. The desired buffer width and height is rotated by the transform hint.
3. The producer dequeues a buffer of the new pre-rotated size.
4. The producer renders to the buffer such that the image is already transformed, that is applying the transform hint to the rendering.
5. The producer applies the inverse transform hint to the buffer it just rendered.
6. The producer queues the pre-transformed buffer with the buffer transform.
7. The composer combines the buffer transform with the display transform. If the buffer transform happens to cancel out the display transform then no rotation is needed and there will be no performance penalties.
Note, when using ANativeWindow APIs in conjunction with a NativeActivity Surface or SurfaceView Surface, the buffer producer will already have access to the transform hint and no additional work is needed.
Java documentation for android.view.AttachedSurfaceControl.getBufferTransformHint().
Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.