+/**
+ * @brief The output functions for a backend module.
+ */
+typedef struct _tdm_func_output {
+ /**
+ * @brief Get the capabilities of a output object
+ * @param[in] output A output object
+ * @param[out] caps The capabilities of a output object
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @remark
+ * A backend module @b SHOULD implement this function. TDM calls this function
+ * not only at the initial time, but also at the update time when new output
+ * is connected.\n
+ * #tdm_caps_output contains connection status, modes, avaiable properties,
+ * size restriction information, etc.
+ */
+ tdm_error (*output_get_capability)(tdm_output *output, tdm_caps_output *caps);
+
+ /**
+ * @brief Get a layer array of a output object
+ * @param[in] output A output object
+ * @param[out] count The count of layers
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A layer array which is @b newly-allocated
+ * @remark
+ * A backend module @b SHOULD implement this function. TDM calls this function
+ * not only at the initial time, but also at the update time when new output
+ * is connected.\n
+ * A backend module @b SHOULD return the @b newly-allocated array which contains
+ * "tdm_layer*" data. It will be freed in frontend.
+ */
+ tdm_layer **(*output_get_layers)(tdm_output *output, int *count,
+ tdm_error *error);
+
+ /**
+ * @brief Set the property which has a given id
+ * @param[in] output A output object
+ * @param[in] id The property id
+ * @param[in] value The value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_set_property)(tdm_output *output, unsigned int id,
+ tdm_value value);
+
+ /**
+ * @brief Get the property which has a given id
+ * @param[in] output A output object
+ * @param[in] id The property id
+ * @param[out] value The value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_get_property)(tdm_output *output, unsigned int id,
+ tdm_value *value);
+
+ /**
+ * @brief Wait for VBLANK
+ * @param[in] output A output object
+ * @param[in] interval vblank interval
+ * @param[in] sync 0: asynchronous, 1:synchronous
+ * @param[in] user_data The user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see output_set_vblank_handler, tdm_output_vblank_handler
+ * @remark
+ * If this function returns TDM_ERROR_NONE, a backend module @b SHOULD call
+ * a user vblank handler with the user data of this function after interval
+ * vblanks.
+ */
+ tdm_error (*output_wait_vblank)(tdm_output *output, int interval, int sync,
+ void *user_data);
+
+ /**
+ * @brief Set a user vblank handler
+ * @param[in] output A output object
+ * @param[in] func A user vblank handler
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_set_vblank_handler)(tdm_output *output,
+ tdm_output_vblank_handler func);
+
+ /**
+ * @brief Commit changes for a output object
+ * @param[in] output A output object
+ * @param[in] sync 0: asynchronous, 1:synchronous
+ * @param[in] user_data The user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see output_set_commit_handler, tdm_output_commit_handler
+ * @remark
+ * When this function is called, a backend module @b SHOULD apply the all
+ * changes of the given output object to screen as well as the layer changes
+ * of this output.
+ * If this function returns TDM_ERROR_NONE, a backend module @b SHOULD call
+ * a user commit handler with the user data of this function after all
+ * changes of the given output object are applied.
+ */
+ tdm_error (*output_commit)(tdm_output *output, int sync, void *user_data);
+
+ /**
+ * @brief Set a user commit handler
+ * @param[in] output A output object
+ * @param[in] func A user commit handler
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_set_commit_handler)(tdm_output *output,
+ tdm_output_commit_handler func);
+
+ /**
+ * @brief Set DPMS of a output object synchronously
+ * @param[in] output A output object
+ * @param[in] dpms_value DPMS value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_set_dpms)(tdm_output *output, tdm_output_dpms dpms_value);
+
+ /**
+ * @brief Get DPMS of a output object
+ * @param[in] output A output object
+ * @param[out] dpms_value DPMS value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_get_dpms)(tdm_output *output, tdm_output_dpms *dpms_value);
+
+ /**
+ * @brief Set one of available modes of a output object
+ * @param[in] output A output object
+ * @param[in] mode A output mode
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_set_mode)(tdm_output *output, const tdm_output_mode *mode);
+
+ /**
+ * @brief Get the mode of a output object
+ * @param[in] output A output object
+ * @param[out] mode A output mode
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*output_get_mode)(tdm_output *output, const tdm_output_mode **mode);
+
+ /**
+ * @brief Create a capture object of a output object
+ * @param[in] output A output object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A capture object
+ * @see capture_destroy() function of #tdm_func_capture
+ * @remark
+ * A backend module doesn't need to implement this function if a hardware
+ * doesn't have the capture device.
+ */
+ tdm_capture *(*output_create_capture)(tdm_output *output, tdm_error *error);
+
+ /**
+ * @brief Set a output connection status handler
+ * @details A backend module need to call the output status handler when the
+ * output connection status has been changed to let the TDM frontend know
+ * the change.
+ * @param[in] output A output object
+ * @param[in] func A output status handler
+ * @param[in] user_data The user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 1.1.0
+ */
+ tdm_error (*output_set_status_handler)(tdm_output *output,
+ tdm_output_status_handler func,
+ void *user_data);
+
+ /**
+ * @brief Set a output dpms handler
+ * @details This function can be NULL if an output doesn't support asynchronous
+ * DPMS control. Otherwise, a backend module needs to call the output dpms handler
+ * to let the TDM frontend know the output DPMS change indeed.
+ * @param[in] output A output object
+ * @param[in] func A output dpms handler
+ * @param[in] user_data The user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see #output_set_dpms_async, #TDM_OUTPUT_CAPABILITY_ASYNC_DPMS
+ * @since 1.4.0
+ */
+ tdm_error (*output_set_dpms_handler)(tdm_output *output,
+ tdm_output_dpms_handler func,
+ void *user_data);
+
+ /**
+ * @brief Set DPMS of a output object asynchronously
+ * @param[in] output A output object
+ * @details This function can be NULL if an output doesn't support asynchronous
+ * DPMS control. Otherwise, an output should have #TDM_OUTPUT_CAPABILITY_ASYNC_DPMS
+ * flags which #output_get_capability returns. And if a output dpms handler is added with
+ * #output_set_dpms_handler, a backend module needs to call the output dpms handler
+ * to let the TDM frontend know the output DPMS change indeed.
+ * @param[in] dpms_value DPMS value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see #output_set_dpms_handler, #TDM_OUTPUT_CAPABILITY_ASYNC_DPMS
+ * @since 1.7.0
+ */
+ tdm_error (*output_set_dpms_async)(tdm_output *output, tdm_output_dpms dpms_value);
+
+ /**
+ * @brief Get a hwc object of a output object
+ * @param[in] output A output object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A hwc object
+ */
+ tdm_hwc *(*output_get_hwc)(tdm_output *output, tdm_error *error);
+
+ void (*reserved5)(void);
+ void (*reserved6)(void);
+ void (*reserved7)(void);
+ void (*reserved8)(void);
+} tdm_func_output;
+
+/**
+ * @brief The layer functions for a backend module.
+ */
+typedef struct _tdm_func_layer {
+ /**
+ * @brief Get the capabilities of a layer object
+ * @param[in] layer A layer object
+ * @param[out] caps The capabilities of a layer object
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @remark
+ * A backend module @b SHOULD implement this function. TDM calls this function
+ * not only at the initial time, but also at the update time when new output
+ * is connected.\n
+ * #tdm_caps_layer contains avaiable formats/properties, zpos information, etc.
+ */
+ tdm_error (*layer_get_capability)(tdm_layer *layer, tdm_caps_layer *caps);
+
+ /**
+ * @brief Set the property which has a given id.
+ * @param[in] layer A layer object
+ * @param[in] id The property id
+ * @param[in] value The value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*layer_set_property)(tdm_layer *layer, unsigned int id,
+ tdm_value value);
+
+ /**
+ * @brief Get the property which has a given id.
+ * @param[in] layer A layer object
+ * @param[in] id The property id
+ * @param[out] value The value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*layer_get_property)(tdm_layer *layer, unsigned int id,
+ tdm_value *value);
+
+ /**
+ * @brief Set the geometry information to a layer object
+ * @param[in] layer A layer object
+ * @param[in] info The geometry information
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see output_commit() function of #tdm_func_output
+ * @remark
+ * A backend module would apply the geometry information when the output object
+ * of a layer object is committed.
+ */
+ tdm_error (*layer_set_info)(tdm_layer *layer, tdm_info_layer *info);
+
+ /**
+ * @brief Get the geometry information to a layer object
+ * @param[in] layer A layer object
+ * @param[out] info The geometry information
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*layer_get_info)(tdm_layer *layer, tdm_info_layer *info);
+
+ /**
+ * @brief Set a TDM buffer to a layer object
+ * @param[in] layer A layer object
+ * @param[in] buffer A TDM buffer
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see output_commit() function of #tdm_func_output
+ * @remark
+ * A backend module would show a TDM buffer on screen when the output object
+ * of a layer object is committed.
+ */
+ tdm_error (*layer_set_buffer)(tdm_layer *layer, tbm_surface_h buffer);
+
+ /**
+ * @brief Unset a TDM buffer from a layer object
+ * @param[in] layer A layer object
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @remark
+ * A backend module @b SHOULD remove the current showing buffer from screen.
+ */
+ tdm_error (*layer_unset_buffer)(tdm_layer *layer);
+
+ /**
+ * @brief Set the zpos for a VIDEO layer object
+ * @param[in] layer A layer object
+ * @param[in] zpos z-order
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see tdm_caps_layer, tdm_layer_capability
+ * @remark
+ * A backend module doesn't need to implement this function if a backend
+ * module doesn't have VIDEO layers.\n
+ * This function is for VIDEO layers.
+ * GRAPHIC layers are non-changeable. The zpos of GRAPHIC layers starts
+ * from 0. If there are 4 GRAPHIC layers, The zpos SHOULD be 0, 1, 2, 3.\n
+ * But the zpos of VIDEO layer is changeable. And The zpos of VIDEO layers
+ * is less than GRAPHIC layers or more than GRAPHIC layers.
+ * ie, ..., -2, -1, 4, 5, ... (if 0 <= GRAPHIC layer's zpos < 4).
+ * The zpos of VIDEO layers is @b relative. It doesn't need to start
+ * from -1 or 4. Let's suppose that there are two VIDEO layers.
+ * One has -2 zpos. Another has -4 zpos. Then -2 Video layer is higher
+ * than -4 VIDEO layer.
+ */
+ tdm_error (*layer_set_video_pos)(tdm_layer *layer, int zpos);
+
+ /**
+ * @brief Create a capture object of a layer object
+ * @param[in] output A output object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A capture object
+ * @see capture_destroy() function of #tdm_func_capture
+ * @remark
+ * A backend module doesn't need to implement this function if a hardware
+ * doesn't have the capture device.
+ */
+ tdm_capture *(*layer_create_capture)(tdm_layer *layer, tdm_error *error);
+
+ /**
+ * @brief Get buffer flags which the layer can support.
+ * @param[in] layer A layer object
+ * @param[out] flags The buffer flags which should be the tbm_bo flags
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*layer_get_buffer_flags)(tdm_layer *layer, unsigned int *flags);
+
+ void (*reserved1)(void);
+ void (*reserved2)(void);
+ void (*reserved3)(void);
+ void (*reserved4)(void);
+ void (*reserved5)(void);
+ void (*reserved6)(void);
+ void (*reserved7)(void);
+} tdm_func_layer;
+
+typedef struct _tdm_func_hwc {
+ /**
+ * @brief Create a new window on the given hwc.
+ * @param[in] hwc A hwc object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A created window object
+ * @since 2.0.0
+ */
+ tdm_hwc_window *(*hwc_create_window)(tdm_hwc *hwc, tdm_error *error);
+
+ /**
+ * @brief Get the supported format array for the hwc windows of a hwc object.
+ * @param[in] hwc A hwc object
+ * @param[out] formats The available format array
+ * @param[out] count The count of formats
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_get_supported_formats)(tdm_hwc *hwc, const tbm_format **formats,
+ int *count);
+
+
+ /**
+ * @brief Get the available property array of a hwc object.
+ * @param[in] hwc A hwc object
+ * @param[out] props The available property array
+ * @param[out] count The count of properties
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_get_available_properties)(tdm_hwc *hwc, const tdm_prop **props,
+ int *count);
+
+ /**
+ * @brief Get a target buffer queue
+ * @param[in] hwc A hwc object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A buffer queue
+ * @since 2.0.0
+ */
+ tbm_surface_queue_h (*hwc_get_client_target_buffer_queue)(tdm_hwc *hwc,
+ tdm_error *error);
+
+ /**
+ * @brief Set the client(relative to the TDM) target buffer
+ * @details Sets the buffer which will receive the hwc of client composition.
+ * Window marked as TDM_COMPOSITION_CLIENT or TDM_COMPOSITION_DEVICE_CANDIDATE
+ * will be composited into this buffer prior to the call to hwc_commit(),
+ * and windows not marked as TDM_COMPOSITION_CLIENT and
+ * TDM_COMPOSITION_DEVICE_CANDIDATE should be composited with this buffer by the
+ * device.
+ *
+ * The buffer handle provided may be null if no windows are being composited by
+ * the client. This must not result in an error (unless an invalid display
+ * handle is also provided).
+ *
+ * The damage parameter describes a buffer damage region as defined in the
+ * description of hwc_window_set_buffer_damage().
+ *
+ * Will be called before hwc_commit() if any of the layers are marked as
+ * TDM_COMPOSITION_CLIENT or TDM_COMPOSITION_DEVICE_CANDIDATE. If no layers are
+ * so marked, then it is not necessary to call this function. It is not necessary
+ * to call hwc_validate() after changing the target through this function.
+ * @param[in] hwc A hwc object
+ * @param[in] target The new target buffer
+ * @param[in] damage The buffer damage region
+ * @param[in] composited_wnds The array of composited hwc_wnds
+ * @param[in] num_wnds The size of #composited_wnds array
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+ tdm_error (*hwc_set_client_target_buffer)(tdm_hwc *hwc,
+ tbm_surface_h target_buffer,
+ tdm_region damage);
+
+ /**
+ * @brief Validate the hwc
+ * @details Instructs the device to inspect all of the layer state and
+ * determine if there are any composition type changes necessary before
+ * presenting the hwc. Permitted changes are described in the definition
+ * of tdm_composition_t above.
+ * @param[in] hwc A hwc object
+ * @param[out] num_types The number of composition type changes required by
+ * the device; if greater than 0, the client must either set and validate new
+ * types, or call hwc_accept_changes() to accept the changes returned by
+ * hwc_get_changed_composition_types(); must be the same as the number of
+ * changes returned by hwc_get_changed_composition_types (see the
+ * declaration of that function for more information); pointer will be non-NULL
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+ tdm_error (*hwc_validate)(tdm_hwc *hwc, tdm_hwc_window **composited_wnds,
+ uint32_t num_wnds, uint32_t *num_types);
+
+ /**
+ * @brief Get changed composition types
+ * @details Retrieves the windows for which the device requires a different
+ * composition type than had been set prior to the last call to hwc_validate().
+ * The client will either update its state with these types and call
+ * hwc_accept_changes, or will set new types and attempt to validate the
+ * display again.
+ * layers and types may be NULL to retrieve the number of elements which
+ * will be returned. The number of elements returned must be the same as the
+ * value returned in num_types from the last call to hwc_validate().
+ * @param[in] hwc A hwc object
+ * @param[out] num_elements If windows or types were NULL, the number of layers
+ * and types which would have been returned; if both were non-NULL, the
+ * number of elements returned in layers and types, which must not exceed
+ * the value stored in num_elements prior to the call; pointer will be
+ * non-NULL
+ * @param[out] windows An array of windows
+ * @param[out] composition_types An array of composition types, each
+ * corresponding to an element of windows
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+ tdm_error (*hwc_get_changed_composition_types)(tdm_hwc *hwc, uint32_t *num_elements,
+ tdm_hwc_window **hwc_window,
+ tdm_hwc_window_composition *composition_types);
+ /**
+ * @brief Accepts the changes required by the device
+ * @details Accepts the changes required by the device from the previous
+ * hwc_validate() call (which may be queried using
+ * hwc_get_chaged_composition_types()) and revalidates the display. This
+ * function is equivalent to requesting the changed types from
+ * hwc_get_chaged_composition_types(), setting those types on the
+ * corresponding windows, and then calling hwc_validate again.
+ * After this call it must be valid to present this display. Calling this after
+ * hwc_validate() returns 0 changes must succeed with TDM_ERROR_NONE, but
+ * should have no other effect.
+ * @param[in] hwc A hwc object
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+ tdm_error (*hwc_accept_changes)(tdm_hwc *hwc);
+
+ /**
+ * @brief Commit changes for a output object
+ * @param[in] hwc A hwc object
+ * @param[in] sync 0: asynchronous, 1:synchronous
+ * @param[in] user_data The user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see hwc_set_commit_handler, tdm_hwc_commit_handler
+ * @remark
+ * When this function is called, a backend module @b SHOULD apply the all
+ * changes of the given output object to screen as well as the layer changes
+ * of this output.
+ * If this function returns TDM_ERROR_NONE, a backend module @b SHOULD call
+ * a user commit handler with the user data of this function after all
+ * changes of the given output object are applied.
+ */
+ tdm_error (*hwc_commit)(tdm_hwc *hwc, int sync, void *user_data);
+
+ /**
+ * @brief Set a user commit handler
+ * @param[in] hwc A hwc object
+ * @param[in] func A user commit handler
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_set_commit_handler)(tdm_output *hwc, tdm_hwc_commit_handler func);
+} tdm_func_hwc;
+
+/**
+ * @brief The window functions for a backend module.
+ * @since 2.0.0
+ */
+typedef struct _tdm_func_hwc_window {
+ /**
+ * @brief Destroys the given window.
+ * @param[in] window the pointer of the window to destroy
+ * @since 2.0.0
+ */
+ void (*hwc_window_destroy)(tdm_hwc_window *hwc_window);
+
+ /**
+ * @brief Get a buffer queue for the window object
+ * @param[in] hwc_window A window object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A buffer queue
+ */
+ tbm_surface_queue_h (*hwc_window_get_buffer_queue)(tdm_hwc_window *hwc_window,
+ tdm_error *error);
+
+ /**
+ * @brief Sets the desired composition type of the given window.
+ * @details During hwc_validate(), the device may request changes to
+ * the composition types of any of the layers as described in the definition
+ * of tdm_hwc_window_composition_t above.
+ * @param[in] hwc_window A window object
+ * @param[in] composition_type The new composition type
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_window_set_composition_type)(tdm_hwc_window *hwc_window,
+ tdm_hwc_window_composition composition_type);
+
+ /**
+ * @brief Set the buffer damage
+ * @details Provides the region of the source buffer which has been modified
+ * since the last frame. This region does not need to be validated before
+ * calling hwc_commit().
+ * Once set through this function, the damage region remains the same until a
+ * subsequent call to this function.
+ * If damage.num_rects > 0, then it may be assumed that any portion of the source
+ * buffer not covered by one of the rects has not been modified this frame. If
+ * damage.num_rects == 0, then the whole source buffer must be treated as if it
+ * has been modified.
+ * If the layer's contents are not modified relative to the prior frame, damage
+ * will contain exactly one empty rect([0, 0, 0, 0]).
+ * The damage rects are relative to the pre-transformed buffer, and their origin
+ * is the top-left corner. They will not exceed the dimensions of the latched
+ * buffer.
+ * @param[in] hwc_window A window object
+ * @param[in] damage The new buffer damage region
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_window_set_buffer_damage)(tdm_hwc_window *hwc_window,
+ tdm_region damage);
+
+ /**
+ * @brief Set the information to a window object
+ * @details The information will be applied when the hwc object
+ * of a layer object is committed.
+ * @param[in] hwc_window A window object
+ * @param[in] info The geometry information
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_window_set_info)(tdm_hwc_window *hwc_window,
+ tdm_hwc_window_info *info);
+
+ /**
+ * @brief Get the geometry information to a layer object
+ * @param[in] layer A layer object
+ * @param[out] info The geometry information
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_window_get_info)(tdm_hwc_window *hwc_window,
+ tdm_hwc_window_info *info);
+
+ /**
+ * @brief Set a TDM buffer to a window object
+ * @details A TDM buffer will be applied when the hwc object
+ * of a layer object is committed.
+ * @param[in] hwc_window A window object
+ * @param[in] buffer A TDM buffer
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ *
+ * Implementation should return #TDM_ERROR_BUSY if #hwc_window can't
+ * be updated right now, this won't be interpreted like some critical
+ * error.
+ */
+ tdm_error (*hwc_window_set_buffer)(tdm_hwc_window *hwc_window,
+ tbm_surface_h buffer);
+
+ /**
+ * @brief Set the property which has a given id.
+ * @param[in] hwc window A hwc window object
+ * @param[in] id The property id
+ * @param[in] value The value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_window_set_property)(tdm_hwc_window *hwc_window,
+ uint32_t id, tdm_value value);
+
+ /**
+ * @brief Get the property which has a given id.
+ * @param[in] hwc window A hwc window object
+ * @param[in] id The property id
+ * @param[out] value The value
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*hwc_window_get_property)(tdm_hwc_window *hwc_window,
+ uint32_t id, tdm_value *value);
+} tdm_func_hwc_window;
+
+/**
+ * @brief The pp functions for a backend module.
+ */
+typedef struct _tdm_func_pp {
+ /**
+ * @brief Destroy a pp object
+ * @param[in] pp A pp object
+ * @see display_create_pp() function of #tdm_func_display
+ */
+ void (*pp_destroy)(tdm_pp *pp);
+
+ /**
+ * @brief Set the geometry information to a pp object
+ * @param[in] pp A pp object
+ * @param[in] info The geometry information
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see pp_commit() function of #tdm_func_pp
+ * @remark
+ * A backend module would apply the geometry information when committed.
+ */
+ tdm_error (*pp_set_info)(tdm_pp *pp, tdm_info_pp *info);
+
+ /**
+ * @brief Attach a source buffer and a destination buffer to a pp object
+ * @param[in] pp A pp object
+ * @param[in] src A source buffer
+ * @param[in] dst A destination buffer
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @see pp_set_info() function of #tdm_func_pp
+ * @see pp_commit() function of #tdm_func_pp
+ * @see pp_set_done_handler, tdm_pp_done_handler
+ * @remark
+ * A backend module converts the image of a source buffer to a destination
+ * buffer when committed. The size/crop/transform information is set via
+ * #pp_set_info() of #tdm_func_pp. When done, a backend module @b SHOULD
+ * return the source/destination buffer via tdm_pp_done_handler.
+ */
+ tdm_error (*pp_attach)(tdm_pp *pp, tbm_surface_h src, tbm_surface_h dst);
+
+ /**
+ * @brief Commit changes for a pp object
+ * @param[in] pp A pp object
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+ tdm_error (*pp_commit)(tdm_pp *pp);
+
+ /**
+ * @brief Set a user done handler to a pp object
+ * @param[in] pp A pp object
+ * @param[in] func A user done handler
+ * @param[in] user_data user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @remark
+ * A backend module @b SHOULD call #tdm_pp_done_handler when converintg a image is done.
+ */
+ tdm_error (*pp_set_done_handler)(tdm_pp *pp, tdm_pp_done_handler func,
+ void *user_data);
+
+ void (*reserved1)(void);
+ void (*reserved2)(void);
+ void (*reserved3)(void);
+ void (*reserved4)(void);
+ void (*reserved5)(void);
+ void (*reserved6)(void);
+ void (*reserved7)(void);
+ void (*reserved8)(void);