Surface
open class Surface : Parcelable
| kotlin.Any | |
| ↳ | android.view.Surface |
Handle onto a raw buffer that is being managed by the screen compositor.
A Surface is generally created by or from a consumer of image buffers (such as a android.graphics.SurfaceTexture, android.media.MediaRecorder, or android.renderscript.Allocation), and is handed to some kind of producer (such as OpenGL, MediaPlayer, or android.hardware.camera2.CameraDevice#createCaptureSession) to draw into.
Note: A Surface acts like a weak reference to the consumer it is associated with. By itself it will not keep its parent consumer from being reclaimed.
Summary
| Nested classes | |
|---|---|
| open |
Exception thrown when a Canvas couldn't be locked with |
| Constants | |
|---|---|
| static Int |
Change the frame rate even if the transition is going to be non-seamless, i. |
| static Int |
Change the frame rate only if the transition is going to be seamless. |
| static Int |
The surface requests a frame rate that is at least the specified frame rate. |
| static Int |
There are no inherent restrictions on the frame rate of this surface. |
| static Int |
This surface is being used to display content with an inherently fixed frame rate, e. |
| static Int |
Rotation constant: 0 degree rotation (natural orientation) |
| static Int |
Rotation constant: 180 degree rotation. |
| static Int |
Rotation constant: 270 degree rotation. |
| static Int |
Rotation constant: 90 degree rotation. |
| Inherited constants | |
|---|---|
| Public constructors | |
|---|---|
Surface(surfaceTexture: SurfaceTexture!)Create Surface from a |
|
Surface(from: SurfaceControl)Create a Surface associated with a given |
|
| Public methods | |
|---|---|
| open Unit |
Clears the frame rate which was set for this surface. |
| open Int |
Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. |
| open Boolean |
Check if CPU throttling is enabled. |
| open Boolean |
isValid()Returns true if this object holds a valid surface. |
| open Canvas! |
lockCanvas(inOutDirty: Rect!)Gets a |
| open Canvas! |
Gets a |
| open Unit |
readFromParcel(source: Parcel!) |
| open Unit |
release()Release the local reference to the server-side surface. |
| open Unit |
setFrameRate(frameRate: Float, compatibility: Int)Sets the intended frame rate for this surface. |
| open Unit |
setFrameRate(frameRate: Float, compatibility: Int, changeFrameRateStrategy: Int)Sets the intended frame rate for this surface. |
| open Unit |
setProducerThrottlingEnabled(enabled: Boolean)Control CPU throttling for Vulkan/EGL producers. |
| open String |
toString()Returns a string representation of the object. |
| open Unit |
unlockCanvas(canvas: Canvas!) |
| open Unit |
unlockCanvasAndPost(canvas: Canvas!)Posts the new contents of the |
| open Unit |
writeToParcel(dest: Parcel, flags: Int)Flatten this object in to a Parcel. |
| Protected methods | |
|---|---|
| open Unit |
finalize()Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
| Properties | |
|---|---|
| static Parcelable.Creator<Surface!> | |
Constants
CHANGE_FRAME_RATE_ALWAYS
static val CHANGE_FRAME_RATE_ALWAYS: Int
Change the frame rate even if the transition is going to be non-seamless, i.e. with visual interruptions for the user. Non-seamless switches might be used when the benefit of matching the content's frame rate outweighs the cost of the transition, for example when displaying long-running video content.
Value: 1CHANGE_FRAME_RATE_ONLY_IF_SEAMLESS
static val CHANGE_FRAME_RATE_ONLY_IF_SEAMLESS: Int
Change the frame rate only if the transition is going to be seamless.
Value: 0FRAME_RATE_COMPATIBILITY_AT_LEAST
static val FRAME_RATE_COMPATIBILITY_AT_LEAST: Int
The surface requests a frame rate that is at least the specified frame rate. This value should be used for UIs, animations, scrolling and fling, and anything that is not a game or video. For video, use FRAME_RATE_COMPATIBILITY_FIXED_SOURCE instead. For game content, use FRAME_RATE_COMPATIBILITY_DEFAULT.
Value: 2FRAME_RATE_COMPATIBILITY_DEFAULT
static val FRAME_RATE_COMPATIBILITY_DEFAULT: Int
There are no inherent restrictions on the frame rate of this surface. When the system selects a frame rate other than what the app requested, the app will be able to run at the system frame rate without requiring pull down. This value should be used when displaying game content, UIs, and anything that isn't video. In Android version Build.VERSION_CODES.BAKLAVA and above, use FRAME_RATE_COMPATIBILITY_DEFAULT for game content. For other cases, see FRAME_RATE_COMPATIBILITY_FIXED_SOURCE and FRAME_RATE_COMPATIBILITY_AT_LEAST.
Value: 0FRAME_RATE_COMPATIBILITY_FIXED_SOURCE
static val FRAME_RATE_COMPATIBILITY_FIXED_SOURCE: Int
This surface is being used to display content with an inherently fixed frame rate, e.g. a video that has a specific frame rate. When the system selects a frame rate other than what the app requested, the app will need to do pull down or use some other technique to adapt to the system's frame rate. The user experience is likely to be worse (e.g. more frame stuttering) than it would be if the system had chosen the app's requested frame rate. This value should be used for video content.
Value: 1ROTATION_0
static val ROTATION_0: Int
Rotation constant: 0 degree rotation (natural orientation)
Value: 0ROTATION_180
static val ROTATION_180: Int
Rotation constant: 180 degree rotation.
Value: 2ROTATION_270
static val ROTATION_270: Int
Rotation constant: 270 degree rotation.
Value: 3ROTATION_90
static val ROTATION_90: Int
Rotation constant: 90 degree rotation.
Value: 1Public constructors
Surface
Surface(surfaceTexture: SurfaceTexture!)
Create Surface from a SurfaceTexture. Images drawn to the Surface will be made available to the SurfaceTexture, which can attach them to an OpenGL ES texture via SurfaceTexture.updateTexImage. Please note that holding onto the Surface created here is not enough to keep the provided SurfaceTexture from being reclaimed. In that sense, the Surface will act like a weak reference to the SurfaceTexture.
| Parameters | |
|---|---|
surfaceTexture |
SurfaceTexture!: The SurfaceTexture that is updated by this Surface. |
| Exceptions | |
|---|---|
android.view.Surface.OutOfResourcesException |
if the surface could not be created. |
Surface
Surface(from: SurfaceControl)
Create a Surface associated with a given SurfaceControl. Buffers submitted to this surface will be displayed by the system compositor according to the parameters specified by the control. Multiple surfaces may be constructed from one SurfaceControl, but only one can be connected (e.g. have an active EGL context) at a time.
| Parameters | |
|---|---|
from |
SurfaceControl: The SurfaceControl to associate this Surface with. This value cannot be null. |
Public methods
clearFrameRate
open fun clearFrameRate(): Unit
Clears the frame rate which was set for this surface.
This is equivalent to calling setFrameRate(float,int,int) using 0 for frameRate.
Note that this only has an effect for surfaces presented on the display. If this surface is consumed by something other than the system compositor, e.g. a media codec, this call has no effect.
See Also
describeContents
open fun describeContents(): Int
Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. For example, if the object will include a file descriptor in the output of writeToParcel(android.os.Parcel,int), the return value of this method must include the CONTENTS_FILE_DESCRIPTOR bit.
| Return | |
|---|---|
Int |
a bitmask indicating the set of special object types marshaled by this Parcelable object instance. Value is either 0 or
|
isProducerThrottlingEnabled
open fun isProducerThrottlingEnabled(): Boolean
Check if CPU throttling is enabled.
| Return | |
|---|---|
Boolean |
true if back-pressure is enabled, false otherwise. |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
If the native window is invalid. |
See Also
isValid
open fun isValid(): Boolean
Returns true if this object holds a valid surface.
| Return | |
|---|---|
Boolean |
True if it holds a physical surface, so lockCanvas() will succeed. Otherwise returns false. |
lockCanvas
open fun lockCanvas(inOutDirty: Rect!): Canvas!
Gets a Canvas for drawing into this surface. After drawing into the provided Canvas, the caller must invoke unlockCanvasAndPost to post the new contents to the surface.
| Parameters | |
|---|---|
inOutDirty |
Rect!: A rectangle that represents the dirty region that the caller wants to redraw. This function may choose to expand the dirty rectangle if for example the surface has been resized or if the previous contents of the surface were not available. The caller must redraw the entire dirty region as represented by the contents of the inOutDirty rectangle upon return from this function. The caller may also pass null instead, in the case where the entire surface should be redrawn. |
| Return | |
|---|---|
Canvas! |
A canvas for drawing into the surface. |
| Exceptions | |
|---|---|
android.view.Surface.OutOfResourcesException |
If the canvas cannot be locked. |
java.lang.IllegalArgumentException |
If the inOutDirty rectangle is not valid. |
lockHardwareCanvas
open fun lockHardwareCanvas(): Canvas!
Gets a Canvas for drawing into this surface. After drawing into the provided Canvas, the caller must invoke unlockCanvasAndPost to post the new contents to the surface. Unlike lockCanvas(android.graphics.Rect) this will return a hardware-accelerated canvas. See the unsupported drawing operations for a list of what is and isn't supported in a hardware-accelerated canvas. It is also required to fully cover the surface every time lockHardwareCanvas() is called as the buffer is not preserved between frames. Partial updates are not supported.
| Return | |
|---|---|
Canvas! |
A canvas for drawing into the surface. |
| Exceptions | |
|---|---|
java.lang.IllegalStateException |
If the canvas cannot be locked. |
release
open fun release(): Unit
Release the local reference to the server-side surface. Always call release() when you're done with a Surface. This will make the surface invalid.
setFrameRate
open fun setFrameRate(
frameRate: Float,
compatibility: Int
): Unit
Sets the intended frame rate for this surface. Any switching of refresh rates is most probably going to be seamless.
| Parameters | |
|---|---|
frameRate |
Float: Value is 0.0f or greater |
compatibility |
Int: Value is one of the following: |
See Also
setFrameRate
open fun setFrameRate(
frameRate: Float,
compatibility: Int,
changeFrameRateStrategy: Int
): Unit
Sets the intended frame rate for this surface.
On devices that are capable of running the display at different refresh rates, the system may choose a display refresh rate to better match this surface's frame rate. Usage of this API won't introduce frame rate throttling, or affect other aspects of the application's frame production pipeline. However, because the system may change the display refresh rate, calls to this function may result in changes to Choreographer callback timings, and changes to the time interval at which the system releases buffers back to the application.
Note that this only has an effect for surfaces presented on the display. If this surface is consumed by something other than the system compositor, e.g. a media codec, this call has no effect.
| Parameters | |
|---|---|
frameRate |
Float: The intended frame rate of this surface, in frames per second. 0 is a special value that indicates the app will accept the system's choice for the display frame rate, which is the default behavior if this function isn't called. The frameRate parameter does not need to be a valid refresh rate for this device's display - e.g., it's fine to pass 30fps to a device that can only run the display at 60fps. Value is 0.0f or greater |
compatibility |
Int: The frame rate compatibility of this surface. The compatibility value may influence the system's choice of display frame rate. This parameter is ignored when frameRate is 0. Value is one of the following: |
changeFrameRateStrategy |
Int: Whether display refresh rate transitions caused by this surface should be seamless. A seamless transition is one that doesn't have any visual interruptions, such as a black screen for a second or two. This parameter is ignored when frameRate is 0. Value is one of the following: |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
If frameRate, compatibility or changeFrameRateStrategy are invalid. |
See Also
setProducerThrottlingEnabled
open fun setProducerThrottlingEnabled(enabled: Boolean): Unit
Control CPU throttling for Vulkan/EGL producers.
By default Vulkan and EGL producers are CPU throttled when they queue a buffer and the consumer is still processing the previous buffer. In practice, it means that eglSwapBuffers() or vkPresentKHR() calls will stall the CPU until the GPU is done processing the previous frame. This API allows to disable this throttling while queueing a buffer.
While the default it to have throttling enabled, the more correct and efficient behavior is to have it disabled. Unfortunately, some Vulkan applications may inadvertently rely on this stall which effectively behaves as consumer/producer synchronization, albeit, inefficiently. It is therefore recommended to always disable throttling and perform proper synchronization in Vulkan.
If the CPU produces frames faster than the GPU, natural throttling will happen when a buffer is dequeued, based on the size of the queue. This typically happen during the first drawing in OpenGL ES and in vkAcquireNextImageKHR() in Vulkan.
This API has no effect in asynchronous mode, where throttling is always enabled.
| Parameters | |
|---|---|
enabled |
Boolean: true to enable back-pressure, false to disable it. |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
If the native window is invalid. |
See Also
toString
open fun toString(): String
Returns a string representation of the object.
| Return | |
|---|---|
String |
a string representation of the object. |
unlockCanvas
open fununlockCanvas(canvas: Canvas!): Unit
Deprecated: This API has been removed and is not supported. Do not use.
unlockCanvasAndPost
open fun unlockCanvasAndPost(canvas: Canvas!): Unit
Posts the new contents of the Canvas to the surface and releases the Canvas.
| Parameters | |
|---|---|
canvas |
Canvas!: The canvas previously obtained from lockCanvas. |
writeToParcel
open fun writeToParcel(
dest: Parcel,
flags: Int
): Unit
Flatten this object in to a Parcel.
| Parameters | |
|---|---|
dest |
Parcel: The Parcel in which the object should be written. This value cannot be null. |
flags |
Int: Additional flags about how the object should be written. May be 0 or PARCELABLE_WRITE_RETURN_VALUE. Value is either 0 or a combination of the following:
|
Protected methods
finalize
protected open fun finalize(): Unit
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.
The general contract of finalize is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.
The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.
The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.
After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.
The finalize method is never invoked more than once by a Java virtual machine for any given object.
Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.
| Exceptions | |
|---|---|
java.lang.Throwable |
the Exception raised by this method |