android::CameraHardwareInterface Class Reference

CameraHardwareInterface.h defines the interface to the camera hardware abstraction layer, used for setting and getting parameters, live previewing, and taking pictures. More...

#include <CameraHardwareInterface.h>


Public Member Functions

virtual ~CameraHardwareInterface ()
virtual sp< IMemoryHeap > getPreviewHeap () const =0
 Return the IMemoryHeap for the preview image heap.
virtual status_t startPreview (preview_callback cb, void *user)=0
 Start preview mode.
virtual void stopPreview ()=0
 Stop a previously started preview.
virtual status_t autoFocus (autofocus_callback, void *user)=0
 Start auto focus, the callback routine is called once when focusing is complete.
virtual status_t takePicture (shutter_callback, raw_callback, jpeg_callback, void *user)=0
 Take a picture.
virtual status_t cancelPicture (bool cancel_shutter, bool cancel_raw, bool cancel_jpeg)=0
 Cancel a picture that was started with takePicture.
virtual status_t setParameters (const CameraParameters &params)=0
 Set the camera parameters.
virtual CameraParameters getParameters () const =0
 Return the camera parameters.
virtual void release ()=0
 Release the hardware resources owned by this object.
virtual status_t dump (int fd, const Vector< String16 > &args) const =0
 Dump state of the camera hardware.

Detailed Description

CameraHardwareInterface.h defines the interface to the camera hardware abstraction layer, used for setting and getting parameters, live previewing, and taking pictures.

It is a referenced counted interface with RefBase as its base class. CameraService calls openCameraHardware() to retrieve a strong pointer to the instance of this interface and may be called multiple times. The following steps describe a typical sequence:

  1. After CameraService calls openCameraHardware(), getParameters() and setParameters() are used to initialize the camera instance. CameraService calls getPreviewHeap() to establish access to the preview heap so it can be registered with SurfaceFlinger for efficient display updating while in preview mode.
  2. startPreview() is called, which is passed a preview_callback() function and a user parameter. The camera instance then periodically calls preview_callback() each time a new preview frame is available. The callback routine has two parameters: the first is a pointer to the IMemory containing the frame and the second a user parameter. If the preview_callback code needs to use this memory after returning, it must copy the data.

Prior to taking a picture, CameraService calls autofocus() with autofocus_callback() and a user parameter. When auto focusing has completed, the camera instance calls autofocus_callback(), which informs the application whether focusing was successful. The camera instance only calls autofocus_callback() once and it is up to the application to call autoFocus() again if refocusing is desired.

CameraService calls takePicture() to request the camera instance take a picture. This method has two callbacks: raw_callback() and jpeg_callback(). When the raw image is available, raw_callback() is called with a pointer to the IMemory containing the raw image. When the jpeg image is available, jpeg_callback() is called with a pointer to the IMemory containing the jpeg image. As with preview_callback(), the memory must be copied if it's needed after returning.

Definition at line 79 of file CameraHardwareInterface.h.

Constructor & Destructor Documentation

virtual android::CameraHardwareInterface::~CameraHardwareInterface (  )  [inline, virtual]

Definition at line 81 of file CameraHardwareInterface.h.

Member Function Documentation

virtual sp<IMemoryHeap> android::CameraHardwareInterface::getPreviewHeap (  )  const [pure virtual]

Return the IMemoryHeap for the preview image heap.

virtual status_t android::CameraHardwareInterface::startPreview ( preview_callback  cb,
void *  user 
) [pure virtual]

Start preview mode.

When a preview image is available preview_callback is called with the user parameter. The call back parameter may be null.

virtual void android::CameraHardwareInterface::stopPreview (  )  [pure virtual]

Stop a previously started preview.

virtual status_t android::CameraHardwareInterface::autoFocus ( autofocus_callback  ,
void *  user 
) [pure virtual]

Start auto focus, the callback routine is called once when focusing is complete.

autoFocus() will be called again if another auto focus is needed.

virtual status_t android::CameraHardwareInterface::takePicture ( shutter_callback  ,
raw_callback  ,
jpeg_callback  ,
void *  user 
) [pure virtual]

Take a picture.

The raw_callback is called when the uncompressed image is available. The jpeg_callback is called when the compressed image is available. These call backs may be null. The user parameter is passed to each of the call back routines.

virtual status_t android::CameraHardwareInterface::cancelPicture ( bool  cancel_shutter,
bool  cancel_raw,
bool  cancel_jpeg 
) [pure virtual]

Cancel a picture that was started with takePicture.

You may cancel any of the shutter, raw, or jpeg callbacks. Calling this method when no picture is being taken is a no-op.

virtual status_t android::CameraHardwareInterface::setParameters ( const CameraParameters &  params  )  [pure virtual]

Set the camera parameters.

virtual CameraParameters android::CameraHardwareInterface::getParameters (  )  const [pure virtual]

Return the camera parameters.

virtual void android::CameraHardwareInterface::release (  )  [pure virtual]

Release the hardware resources owned by this object.

Note that this is *not* done in the destructor.

virtual status_t android::CameraHardwareInterface::dump ( int  fd,
const Vector< String16 > &  args 
) const [pure virtual]

Dump state of the camera hardware.

The documentation for this class was generated from the following file: