@@ -44,13 +44,18 @@ template <typename Pixel> class Display : public BaseComponent {
4444 /* *
4545 * @brief Callback for lvgl to flush segments of pixel data from the pixel
4646 * buffers to the display.
47+ * @param disp The display to flush data to.
48+ * @param area The area of the display to flush data to.
49+ * @param color_map The color data to flush to the display.
4750 */
48- using flush_fn = lv_display_flush_cb_t ;
51+ typedef std::function<void (lv_display_t *disp, const lv_area_t *area, uint8_t *color_map)>
52+ flush_fn;
4953
5054 /* *
5155 * @brief Callback for lvgl event handler to reconfigure the display hardware.
56+ * @param rotation The new rotation setting for the display.
5257 */
53- typedef void (*rotation_fn)( const DisplayRotation &rotation);
58+ typedef std::function< void ( const DisplayRotation &rotation)> rotation_fn ;
5459
5560 /* *
5661 * @brief Callback for setting the display brightness.
@@ -325,20 +330,64 @@ template <typename Pixel> class Display : public BaseComponent {
325330 */
326331 size_t vram_size_bytes () const { return display_buffer_px_size_ * sizeof (Pixel); }
327332
333+ /* *
334+ * @brief Set the rotation of the display.
335+ * @note This function is called by the event handler when the display
336+ * resolution changes, so that the display hardware can be reconfigured
337+ * to match the new software rotation setting.
338+ * @param rotation The new rotation setting for the display.
339+ */
340+ void set_rotation (DisplayRotation rotation) {
341+ if (rotation_callback_ != nullptr ) {
342+ rotation_callback_ (rotation);
343+ }
344+ }
345+
346+ /* *
347+ * @brief Flush the data to the display.
348+ * @warning This function is called by the LVGL flush callback, so it is
349+ * recommended to not call this function directly.
350+ * @param disp The display to flush data to.
351+ * @param area The area of the display to flush data to.
352+ * @param color_map The color data to flush to the display.
353+ */
354+ void flush (lv_display_t *disp, const lv_area_t *area, uint8_t *color_map) {
355+ if (flush_callback_ != nullptr ) {
356+ flush_callback_ (disp, area, color_map);
357+ }
358+ }
359+
328360protected:
329361 /* *
330362 * @brief LVGL event handler.
363+ * @param event The event to handle.
331364 */
332365 static void event_cb (lv_event_t *event) {
333366 if (lv_event_get_code (event) == LV_EVENT_RESOLUTION_CHANGED) {
334- auto rotation = lv_display_get_rotation (lv_display_get_default ());
335- auto rotation_callback = reinterpret_cast <rotation_fn>(lv_event_get_user_data (event));
336- if (rotation_callback != nullptr ) {
337- rotation_callback (static_cast <DisplayRotation>(rotation));
367+ auto rotation =
368+ static_cast <DisplayRotation>(lv_display_get_rotation (lv_display_get_default ()));
369+ auto display = static_cast <Display *>(lv_display_get_user_data (lv_disp_get_default ()));
370+ if (display != nullptr ) {
371+ display->set_rotation (rotation);
338372 }
339373 }
340374 };
341375
376+ /* *
377+ * @brief Callback for the LVGL flush function to call when it needs to flush
378+ * data to the display.
379+ * @param disp The display to flush data to.
380+ * @param area The area of the display to flush data to.
381+ * @param color_map The color data to flush to the display.
382+ */
383+ static void flush_cb (lv_display_t *disp, const lv_area_t *area, uint8_t *color_map) {
384+ // use the display to call the registered flush callback appropriately
385+ auto display = static_cast <Display *>(lv_display_get_user_data (disp));
386+ if (display != nullptr ) {
387+ display->flush (disp, area, color_map);
388+ }
389+ }
390+
342391 /* *
343392 * @brief Initialize the lvgl subsystem, display buffer configuration, and
344393 * display driver. Start the task to run the high-priority lvgl
@@ -350,19 +399,31 @@ template <typename Pixel> class Display : public BaseComponent {
350399 */
351400 void init_gfx (const flush_fn flush_callback, const rotation_fn rotation_callback,
352401 DisplayRotation rotation, const Task::BaseConfig &task_config) {
402+ // save the callbacks
403+ if (flush_callback == nullptr ) {
404+ logger_.error (" No flush callback provided, cannot initialize display!"
405+ assert (false ); // cannot continue without a flush callback
406+ }
407+ flush_callback_ = flush_callback;
408+ if (rotation_callback == nullptr ) {
409+ logger_.warn (" No rotation callback provided, resolution changed event will not automatically "
410+ " update the display hardware rotation."
411+ }
412+ rotation_callback_ = rotation_callback;
413+
353414 lv_init ();
354415
355416 display_ = lv_display_create (width_, height_);
417+ // store a pointer to this object in the display user data, so that we can
418+ // access it in the flush callback
419+ lv_display_set_user_data (display_, this );
356420
357421 // Configure the lvgl display buffer with our pixel buffers
358422 lv_display_set_buffers (display_, vram_0_, vram_1_, vram_size_bytes (),
359423 LV_DISPLAY_RENDER_MODE_PARTIAL);
360- lv_display_set_flush_cb (display_, flush_callback );
424+ lv_display_set_flush_cb (display_, Display::flush_cb );
361425
362- if (rotation_callback != nullptr ) {
363- lv_display_add_event_cb (display_, event_cb, LV_EVENT_RESOLUTION_CHANGED,
364- reinterpret_cast <void *>(rotation_callback));
365- }
426+ lv_display_add_event_cb (display_, event_cb, LV_EVENT_RESOLUTION_CHANGED, this );
366427
367428 lv_display_set_rotation (display_, static_cast <lv_display_rotation_t >(rotation));
368429
@@ -449,6 +510,8 @@ template <typename Pixel> class Display : public BaseComponent {
449510 std::unique_ptr<Task> task_;
450511 size_t width_;
451512 size_t height_;
513+ flush_fn flush_callback_{nullptr };
514+ rotation_fn rotation_callback_{nullptr };
452515 size_t display_buffer_px_size_;
453516 Pixel *vram_0_{nullptr };
454517 Pixel *vram_1_{nullptr };
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