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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H
#define HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H
#include <hardware/camera.h>
#include <utils/Errors.h>
#include <utils/Mutex.h>
#include <utils/Timers.h>
/*
* Contains declaration of a class PreviewWindow that encapsulates functionality
* of a preview window set via set_preview_window camera HAL API.
*/
namespace android {
class EmulatedCameraDevice;
/* Encapsulates functionality of a preview window set via set_preview_window
* camera HAL API.
*
* Objects of this class are contained in EmulatedCamera objects, and handle
* relevant camera API callbacks.
*/
class PreviewWindow {
public:
/* Constructs PreviewWindow instance. */
PreviewWindow();
/* Destructs PreviewWindow instance. */
~PreviewWindow();
/***************************************************************************
* Camera API
**************************************************************************/
public:
/* Actual handler for camera_device_ops_t::set_preview_window callback.
* This method is called by the containing emulated camera object when it is
* handing the camera_device_ops_t::set_preview_window callback.
* Param:
* window - Preview window to set. This parameter might be NULL, which
* indicates preview window reset.
* preview_fps - Preview's frame frequency. This parameter determins when
* a frame received via onNextFrameAvailable call will be pushed to
* the preview window. If 'window' parameter passed to this method is
* NULL, this parameter is ignored.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
status_t setPreviewWindow(struct preview_stream_ops* window, int preview_fps);
/* Starts the preview.
* This method is called by the containing emulated camera object when it is
* handing the camera_device_ops_t::start_preview callback.
*/
status_t startPreview();
/* Stops the preview.
* This method is called by the containing emulated camera object when it is
* handing the camera_device_ops_t::start_preview callback.
*/
void stopPreview();
/* Checks if preview is enabled. */
inline bool isPreviewEnabled() { return mPreviewEnabled; }
/****************************************************************************
* Public API
***************************************************************************/
public:
/* Next frame is available in the camera device.
* This is a notification callback that is invoked by the camera device when
* a new frame is available.
* Note that most likely this method is called in context of a worker thread
* that camera device has created for frame capturing.
* Param:
* frame - Captured frame, or NULL if camera device didn't pull the frame
* yet. If NULL is passed in this parameter use GetCurrentFrame method
* of the camera device class to obtain the next frame. Also note that
* the size of the frame that is passed here (as well as the frame
* returned from the GetCurrentFrame method) is defined by the current
* frame settings (width + height + pixel format) for the camera device.
* timestamp - Frame's timestamp.
* camera_dev - Camera device instance that delivered the frame.
*/
void onNextFrameAvailable(const void* frame, nsecs_t timestamp,
EmulatedCameraDevice* camera_dev);
/***************************************************************************
* Private API
**************************************************************************/
protected:
/* Adjusts cached dimensions of the preview window frame according to the
* frame dimensions used by the camera device.
*
* When preview is started, it's not known (hard to define) what are going
* to be the dimensions of the frames that are going to be displayed. Plus,
* it might be possible, that such dimensions can be changed on the fly. So,
* in order to be always in sync with frame dimensions, this method is
* called for each frame passed to onNextFrameAvailable method, in order to
* properly adjust frame dimensions, used by the preview window.
* Note that this method must be called while object is locked.
* Param:
* camera_dev - Camera device, prpviding frames displayed in the preview
* window.
* Return:
* true if cached dimensions have been adjusted, or false if cached
* dimensions match device's frame dimensions.
*/
bool adjustPreviewDimensions(EmulatedCameraDevice* camera_dev);
/* Checks if it's the time to push new frame to the preview window.
* Note that this method must be called while object is locked. */
bool isPreviewTime();
/***************************************************************************
* Data members
**************************************************************************/
protected:
/* Locks this instance for data changes. */
Mutex mObjectLock;
/* Preview window instance. */
preview_stream_ops* mPreviewWindow;
/* Timestamp (abs. microseconds) when last frame has been pushed to the
* preview window. */
uint64_t mLastPreviewed;
/* Preview frequency in microseconds. */
uint32_t mPreviewAfter;
/*
* Cached preview window frame dimensions.
*/
int mPreviewFrameWidth;
int mPreviewFrameHeight;
/* Preview status. */
bool mPreviewEnabled;
};
}; /* namespace android */
#endif /* HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H */
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