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 #include <hardware/camera.h> 21 #include <utils/Errors.h> 22 #include <utils/Mutex.h> 23 #include <utils/Timers.h> 24 25 /* 26 * Contains declaration of a class PreviewWindow that encapsulates functionality 27 * of a preview window set via set_preview_window camera HAL API. 28 */ 29 30 namespace android { 31 32 class EmulatedCameraDevice; 33 34 /* Encapsulates functionality of a preview window set via set_preview_window 35 * camera HAL API. 36 * 37 * Objects of this class are contained in EmulatedCamera objects, and handle 38 * relevant camera API callbacks. 39 */ 40 class PreviewWindow { 41 public: 42 /* Constructs PreviewWindow instance. */ 43 PreviewWindow(); 44 45 /* Destructs PreviewWindow instance. */ 46 ~PreviewWindow(); 47 48 /*************************************************************************** 49 * Camera API 50 **************************************************************************/ 51 52 public: 53 /* Actual handler for camera_device_ops_t::set_preview_window callback. 54 * This method is called by the containing emulated camera object when it is 55 * handing the camera_device_ops_t::set_preview_window callback. 56 * Param: 57 * window - Preview window to set. This parameter might be NULL, which 58 * indicates preview window reset. 59 * preview_fps - Preview's frame frequency. This parameter determins when 60 * a frame received via onNextFrameAvailable call will be pushed to 61 * the preview window. If 'window' parameter passed to this method is 62 * NULL, this parameter is ignored. 63 * Return: 64 * NO_ERROR on success, or an appropriate error status. 65 */ 66 status_t setPreviewWindow(struct preview_stream_ops* window, int preview_fps); 67 68 /* Starts the preview. 69 * This method is called by the containing emulated camera object when it is 70 * handing the camera_device_ops_t::start_preview callback. 71 */ 72 status_t startPreview(); 73 74 /* Stops the preview. 75 * This method is called by the containing emulated camera object when it is 76 * handing the camera_device_ops_t::start_preview callback. 77 */ 78 void stopPreview(); 79 80 /* Checks if preview is enabled. */ isPreviewEnabled()81 inline bool isPreviewEnabled() { return mPreviewEnabled; } 82 83 /**************************************************************************** 84 * Public API 85 ***************************************************************************/ 86 87 public: 88 /* Next frame is available in the camera device. 89 * This is a notification callback that is invoked by the camera device when 90 * a new frame is available. 91 * Note that most likely this method is called in context of a worker thread 92 * that camera device has created for frame capturing. 93 * Param: 94 * frame - Captured frame, or NULL if camera device didn't pull the frame 95 * yet. If NULL is passed in this parameter use GetCurrentFrame method 96 * of the camera device class to obtain the next frame. Also note that 97 * the size of the frame that is passed here (as well as the frame 98 * returned from the GetCurrentFrame method) is defined by the current 99 * frame settings (width + height + pixel format) for the camera device. 100 * timestamp - Frame's timestamp. 101 * camera_dev - Camera device instance that delivered the frame. 102 */ 103 void onNextFrameAvailable(const void* frame, nsecs_t timestamp, 104 EmulatedCameraDevice* camera_dev); 105 106 /*************************************************************************** 107 * Private API 108 **************************************************************************/ 109 110 protected: 111 /* Adjusts cached dimensions of the preview window frame according to the 112 * frame dimensions used by the camera device. 113 * 114 * When preview is started, it's not known (hard to define) what are going 115 * to be the dimensions of the frames that are going to be displayed. Plus, 116 * it might be possible, that such dimensions can be changed on the fly. So, 117 * in order to be always in sync with frame dimensions, this method is 118 * called for each frame passed to onNextFrameAvailable method, in order to 119 * properly adjust frame dimensions, used by the preview window. 120 * Note that this method must be called while object is locked. 121 * Param: 122 * camera_dev - Camera device, prpviding frames displayed in the preview 123 * window. 124 * Return: 125 * true if cached dimensions have been adjusted, or false if cached 126 * dimensions match device's frame dimensions. 127 */ 128 bool adjustPreviewDimensions(EmulatedCameraDevice* camera_dev); 129 130 /* Checks if it's the time to push new frame to the preview window. 131 * Note that this method must be called while object is locked. */ 132 bool isPreviewTime(); 133 134 /*************************************************************************** 135 * Data members 136 **************************************************************************/ 137 138 protected: 139 /* Locks this instance for data changes. */ 140 Mutex mObjectLock; 141 142 /* Preview window instance. */ 143 preview_stream_ops* mPreviewWindow; 144 145 /* Timestamp (abs. microseconds) when last frame has been pushed to the 146 * preview window. */ 147 uint64_t mLastPreviewed; 148 149 /* Preview frequency in microseconds. */ 150 uint32_t mPreviewAfter; 151 152 /* 153 * Cached preview window frame dimensions. 154 */ 155 156 int mPreviewFrameWidth; 157 int mPreviewFrameHeight; 158 159 /* Preview status. */ 160 bool mPreviewEnabled; 161 }; 162 163 }; /* namespace android */ 164 165 #endif /* HW_EMULATOR_CAMERA_PREVIEW_WINDOW_H */ 166