setPreviewWindow in camera hal

最新推荐文章于 2024-04-13 22:51:02 发布

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本文介绍了 Android Camera Hardware 中 mPreviewWindow 的定义及初始化过程。详细解析了 preview_stream_ops_t 结构体及其成员函数的作用，并展示了如何通过 set_buffers_geometry 设置预览窗口的尺寸和格式。

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1. mPreviewWindow 在hardware/intel/libcamera/CameraHardware.h 中定义

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preview_stream_ops_t* mPreviewWindow;

preview_stream_ops_t* mPreviewWindow;

preview_stream_ops_t 定义：

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1. typedef struct preview_stream_ops {
2. int (*dequeue_buffer)(struct preview_stream_ops* w,
3. buffer_handle_t** buffer, int *stride);
4. int (*enqueue_buffer)(struct preview_stream_ops* w,
5. buffer_handle_t* buffer);
6. int (*cancel_buffer)(struct preview_stream_ops* w,
7. buffer_handle_t* buffer);
8. int (*set_buffer_count)(struct preview_stream_ops* w, int count);
9. int (*set_buffers_geometry)(struct preview_stream_ops* pw,
10. int w, int h, int format);
11. int (*set_crop)(struct preview_stream_ops *w,
12. int left, int top, int right, int bottom);
13. int (*set_usage)(struct preview_stream_ops* w, int usage);
14. int (*set_swap_interval)(struct preview_stream_ops *w, int interval);
15. int (*get_min_undequeued_buffer_count)(const struct preview_stream_ops *w,
16. int *count);
17. int (*lock_buffer)(struct preview_stream_ops* w,
18. buffer_handle_t* buffer);
19. } preview_stream_ops_t;

   1. typedef struct preview_stream_ops {
   2.     int (*dequeue_buffer)(struct preview_stream_ops* w,
   3.                           buffer_handle_t** buffer, int *stride);
   4.     int (*enqueue_buffer)(struct preview_stream_ops* w,
   5.                 buffer_handle_t* buffer);
   6.     int (*cancel_buffer)(struct preview_stream_ops* w,
   7.                 buffer_handle_t* buffer);
   8.     int (*set_buffer_count)(struct preview_stream_ops* w, int count);
   9.     int (*set_buffers_geometry)(struct preview_stream_ops* pw,
  10.                 int w, int h, int format);
  11.     int (*set_crop)(struct preview_stream_ops *w,
  12.                 int left, int top, int right, int bottom);
  13.     int (*set_usage)(struct preview_stream_ops* w, int usage);
  14.     int (*set_swap_interval)(struct preview_stream_ops *w, int interval);
  15.     int (*get_min_undequeued_buffer_count)(const struct preview_stream_ops *w,
  16.                 int *count);
  17.     int (*lock_buffer)(struct preview_stream_ops* w,
  18.                 buffer_handle_t* buffer);
  19. } preview_stream_ops_t;

2. 初始化：

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# if (mPreviewWindow != 0) {
# int preview_width, preview_height;
# mParameters.getPreviewSize(&preview_width, &preview_height);
# mPreviewWindow->set_buffers_geometry(
# mPreviewWindow,
# preview_width,
# preview_height,
# HAL_PIXEL_FORMAT_RGB_565);
# }

# if (mPreviewWindow != 0) {
#         int preview_width, preview_height;
#         mParameters.getPreviewSize(&preview_width, &preview_height);
#         mPreviewWindow->set_buffers_geometry(
#             mPreviewWindow,
#             preview_width,
#             preview_height,
#             HAL_PIXEL_FORMAT_RGB_565);
#     }

mPreviewWindow->set_buffers_geometry（）在/frameworks/base/services/camera/libcameraservice/CameraHardwareInterface.h 中定义

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1. void initHalPreviewWindow()
2. {
3. mHalPreviewWindow.nw.cancel_buffer = __cancel_buffer;
4. mHalPreviewWindow.nw.lock_buffer = __lock_buffer;
5. mHalPreviewWindow.nw.dequeue_buffer = __dequeue_buffer;
6. mHalPreviewWindow.nw.enqueue_buffer = __enqueue_buffer;
7. mHalPreviewWindow.nw.set_buffer_count = __set_buffer_count;
8. mHalPreviewWindow.nw.set_buffers_geometry = __set_buffers_geometry;
9. mHalPreviewWindow.nw.set_crop = __set_crop;
10. mHalPreviewWindow.nw.set_usage = __set_usage;
11. mHalPreviewWindow.nw.set_swap_interval = __set_swap_interval;
12.
13. mHalPreviewWindow.nw.get_min_undequeued_buffer_count =
14. __get_min_undequeued_buffer_count;
15. }
16.
17. sp<ANativeWindow> mPreviewWindow;
18.
19. struct camera_preview_window {
20. struct preview_stream_ops nw;
21. void *user;
22. };
23.
24. struct camera_preview_window mHalPreviewWindow;
__set_buffers_geometry 封装了 native_window_set_buffers_geometry().
1. static int __set_buffers_geometry(struct preview_stream_ops* w,
2. int width, int height, int format)
3. {
4. ANativeWindow *a = anw(w);
5. return native_window_set_buffers_geometry(a,
6. width, height, format);
7. }

   1. void initHalPreviewWindow()
   2.     {
   3.         mHalPreviewWindow.nw.cancel_buffer = __cancel_buffer;
   4.         mHalPreviewWindow.nw.lock_buffer = __lock_buffer;
   5.         mHalPreviewWindow.nw.dequeue_buffer = __dequeue_buffer;
   6.         mHalPreviewWindow.nw.enqueue_buffer = __enqueue_buffer;
   7.         mHalPreviewWindow.nw.set_buffer_count = __set_buffer_count;
   8.         mHalPreviewWindow.nw.set_buffers_geometry = __set_buffers_geometry;
   9.         mHalPreviewWindow.nw.set_crop = __set_crop;
  10.         mHalPreviewWindow.nw.set_usage = __set_usage;
  11.         mHalPreviewWindow.nw.set_swap_interval = __set_swap_interval;
  12.

  13.         mHalPreviewWindow.nw.get_min_undequeued_buffer_count =
  14.                 __get_min_undequeued_buffer_count;
  15.     }
  16.

  17.     sp<ANativeWindow> mPreviewWindow;
  18.

  19.     struct camera_preview_window {
  20.         struct preview_stream_ops nw;
  21.         void *user;
  22.     };
  23.

  24.     struct camera_preview_window mHalPreviewWindow;

__set_buffers_geometry 封装了 native_window_set_buffers_geometry().

   1. static int __set_buffers_geometry(struct preview_stream_ops* w,
   2.                       int width, int height, int format)
   3.     {
   4.         ANativeWindow *a = anw(w);
   5.         return native_window_set_buffers_geometry(a,
   6.                           width, height, format);
   7.     }

native_window_set_buffers_geometry(). 在system/core/include/system/window.h 中定义：

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1. /*
2. * native_window_set_buffers_geometry(..., int w, int h, int format)
3. * All buffers dequeued after this call will have the dimensions and format
4. * specified. A successful call to this function has the same effect as calling
5. * native_window_set_buffers_size and native_window_set_buffers_format.
6. *
7. * XXX: This function is deprecated. The native_window_set_buffers_dimensions
8. * and native_window_set_buffers_format functions should be used instead.
9. */
10. static inline int native_window_set_buffers_geometry(
11. struct ANativeWindow* window,
12. int w, int h, int format)
13. {
14. return window->perform(window, NATIVE_WINDOW_SET_BUFFERS_GEOMETRY,
15. w, h, format);
16. }

   1. /*
   2.  * native_window_set_buffers_geometry(..., int w, int h, int format)
   3.  * All buffers dequeued after this call will have the dimensions and format
   4.  * specified. A successful call to this function has the same effect as calling
   5.  * native_window_set_buffers_size and native_window_set_buffers_format.
   6.  *
   7.  * XXX: This function is deprecated. The native_window_set_buffers_dimensions
   8.  * and native_window_set_buffers_format functions should be used instead.
   9.  */
  10. static inline int native_window_set_buffers_geometry(
  11.         struct ANativeWindow* window,
  12.         int w, int h, int format)
  13. {
  14.     return window->perform(window, NATIVE_WINDOW_SET_BUFFERS_GEOMETRY,
  15.             w, h, format);
  16. }

其他的函数也是类似的调用情况。