upload android base code part6

android/device/generic/goldfish/camera/PreviewWindow.h

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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
+
+/*
+ * 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. The frame is available through the |camera_dev|
+     * object. Remember to use an EmulatedCameraDevice::FrameLock object to
+     * protect access to the frame while using it.
+     * Note that most likely this method is called in context of a worker thread
+     * that camera device has created for frame capturing.
+     * Param:
+     * timestamp - Frame's timestamp.
+     * camera_dev - Camera device instance that delivered the frame.
+     */
+    void onNextFrameAvailable(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);
+
+    /***************************************************************************
+     * Data members
+     **************************************************************************/
+
+protected:
+    /* Locks this instance for data changes. */
+    Mutex                           mObjectLock;
+
+    /* Preview window instance. */
+    preview_stream_ops*             mPreviewWindow;
+
+    /*
+     * Cached preview window frame dimensions.
+     */
+
+    int                             mPreviewFrameWidth;
+    int                             mPreviewFrameHeight;
+
+    /* Preview status. */
+    bool                            mPreviewEnabled;
+};
+
+}; /* namespace android */
+
+#endif  /* HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H */