1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H 18 #define HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H 19 20 /* 21 * Contains declaration of a class PreviewWindow that encapsulates functionality 22 * of a preview window set via set_preview_window camera HAL API. 23 */ 24 25 namespace android { 26 27 class EmulatedCameraDevice; 28 29 /* Encapsulates functionality of a preview window set via set_preview_window 30 * camera HAL API. 31 * 32 * Objects of this class are contained in EmulatedCamera objects, and handle 33 * relevant camera API callbacks. 34 */ 35 class PreviewWindow { 36 public: 37 /* Constructs PreviewWindow instance. */ 38 PreviewWindow(); 39 40 /* Destructs PreviewWindow instance. */ 41 ~PreviewWindow(); 42 43 /*************************************************************************** 44 * Camera API 45 **************************************************************************/ 46 47 public: 48 /* Actual handler for camera_device_ops_t::set_preview_window callback. 49 * This method is called by the containing emulated camera object when it is 50 * handing the camera_device_ops_t::set_preview_window callback. 51 * Param: 52 * window - Preview window to set. This parameter might be NULL, which 53 * indicates preview window reset. 54 * preview_fps - Preview's frame frequency. This parameter determins when 55 * a frame received via onNextFrameAvailable call will be pushed to 56 * the preview window. If 'window' parameter passed to this method is 57 * NULL, this parameter is ignored. 58 * Return: 59 * NO_ERROR on success, or an appropriate error status. 60 */ 61 status_t setPreviewWindow(struct preview_stream_ops* window, 62 int preview_fps); 63 64 /* Starts the preview. 65 * This method is called by the containing emulated camera object when it is 66 * handing the camera_device_ops_t::start_preview callback. 67 */ 68 status_t startPreview(); 69 70 /* Stops the preview. 71 * This method is called by the containing emulated camera object when it is 72 * handing the camera_device_ops_t::start_preview callback. 73 */ 74 void stopPreview(); 75 76 /* Checks if preview is enabled. */ isPreviewEnabled()77 inline bool isPreviewEnabled() 78 { 79 return mPreviewEnabled; 80 } 81 82 /**************************************************************************** 83 * Public API 84 ***************************************************************************/ 85 86 public: 87 /* Next frame is available in the camera device. 88 * This is a notification callback that is invoked by the camera device when 89 * a new frame is available. The frame is available through the |camera_dev| 90 * object. Remember to use an EmulatedCameraDevice::FrameLock object to 91 * protect access to the frame while using it. 92 * Note that most likely this method is called in context of a worker thread 93 * that camera device has created for frame capturing. 94 * Param: 95 * timestamp - Frame's timestamp. 96 * camera_dev - Camera device instance that delivered the frame. 97 */ 98 void onNextFrameAvailable(nsecs_t timestamp, 99 EmulatedCameraDevice* camera_dev); 100 101 /*************************************************************************** 102 * Private API 103 **************************************************************************/ 104 105 protected: 106 /* Adjusts cached dimensions of the preview window frame according to the 107 * frame dimensions used by the camera device. 108 * 109 * When preview is started, it's not known (hard to define) what are going 110 * to be the dimensions of the frames that are going to be displayed. Plus, 111 * it might be possible, that such dimensions can be changed on the fly. So, 112 * in order to be always in sync with frame dimensions, this method is 113 * called for each frame passed to onNextFrameAvailable method, in order to 114 * properly adjust frame dimensions, used by the preview window. 115 * Note that this method must be called while object is locked. 116 * Param: 117 * camera_dev - Camera device, prpviding frames displayed in the preview 118 * window. 119 * Return: 120 * true if cached dimensions have been adjusted, or false if cached 121 * dimensions match device's frame dimensions. 122 */ 123 bool adjustPreviewDimensions(EmulatedCameraDevice* camera_dev); 124 125 /*************************************************************************** 126 * Data members 127 **************************************************************************/ 128 129 protected: 130 /* Locks this instance for data changes. */ 131 Mutex mObjectLock; 132 133 /* Preview window instance. */ 134 preview_stream_ops* mPreviewWindow; 135 136 /* 137 * Cached preview window frame dimensions. 138 */ 139 140 int mPreviewFrameWidth; 141 int mPreviewFrameHeight; 142 143 /* Preview status. */ 144 bool mPreviewEnabled; 145 }; 146 147 }; /* namespace android */ 148 149 #endif /* HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H */ 150