feat(multi-touch): Multi-touch gesture detection in LVGL port

Author: PetrESP

components/esp_lvgl_port/Kconfig

@@ -6,5 +6,10 @@ menu "ESP LVGL PORT"
         default n
         help
             Enables using PPA for screen rotation.
-
+    config LVGL_PORT_ENABLE_GESTURES
+        depends on LV_USE_GESTURE_RECOGNITION
+        bool "Enable gesture detection"
+        default n
+        help
+            Enables gesture detection.
 endmenu

components/esp_lvgl_port/README.md

@@ -275,6 +275,22 @@ Display rotation can be changed at runtime.
 > [!NOTE]
 > During the hardware rotating, the component call [`esp_lcd`](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/lcd.html) API. When using software rotation, you cannot use neither `direct_mode` nor `full_refresh` in the driver. See [LVGL documentation](https://docs.lvgl.io/8.3/porting/display.html?highlight=sw_rotate) for more info.
 
+### Detecting gestures
+
+LVGL includes support for software detection of multi-touch gestures.
+This detection can be enabled by setting the `LVGL_PORT_ENABLE_GESTURES` config and having `ESP_LCD_TOUCH_MAX_POINTS` > 1.
+Example usage of the gesture callback can be found in LVGL [documentation](https://docs.lvgl.io/master/details/main-modules/indev/gestures.html).
+
+The LVGL port task is responsible for passing the touch coordinates to the gesture recognizers and calling the registered callback when a gesture is detected.
+
+To correctly distinguish two finger swipe from rotation, we recommend changing the default value (which is 0) for the rotation threshold.
+From our testing we recommend starting with 0.15 radians.
+
+```
+    lv_indev_t indev = bsp_display_get_input_dev();
+    lv_indev_set_rotation_rad_threshold(indev, 0.15f);
+```
+
 ### Using PSRAM canvas
 
 If the SRAM is insufficient, you can use the PSRAM as a canvas and use a small trans_buffer to carry it, this makes drawing more efficient.

components/esp_lvgl_port/idf_component.yml

@@ -1,4 +1,4 @@
-version: "2.6.3"
+version: "2.6.4"
 description: ESP LVGL port
 url: https://github.com/espressif/esp-bsp/tree/master/components/esp_lvgl_port
 dependencies:

components/esp_lvgl_port/src/lvgl9/esp_lvgl_port_touch.c

@@ -9,6 +9,7 @@
 #include "esp_check.h"
 #include "esp_lcd_touch.h"
 #include "esp_lvgl_port.h"
+#include "esp_timer.h"
 
 static const char *TAG = "LVGL";
 
@@ -117,15 +118,42 @@ static void lvgl_port_touchpad_read(lv_indev_t *indev_drv, lv_indev_data_t *data
     assert(touch_ctx);
     assert(touch_ctx->handle);
 
-    uint16_t touchpad_x[1] = {0};
-    uint16_t touchpad_y[1] = {0};
+    uint16_t touchpad_x[CONFIG_ESP_LCD_TOUCH_MAX_POINTS] = {0};
+    uint16_t touchpad_y[CONFIG_ESP_LCD_TOUCH_MAX_POINTS] = {0};
     uint8_t touchpad_cnt = 0;
 
     /* Read data from touch controller into memory */
     esp_lcd_touch_read_data(touch_ctx->handle);
 
     /* Read data from touch controller */
-    bool touchpad_pressed = esp_lcd_touch_get_coordinates(touch_ctx->handle, touchpad_x, touchpad_y, NULL, &touchpad_cnt, 1);
+    bool touchpad_pressed = esp_lcd_touch_get_coordinates(touch_ctx->handle, touchpad_x, touchpad_y, NULL, &touchpad_cnt, CONFIG_ESP_LCD_TOUCH_MAX_POINTS);
+
+#if (CONFIG_ESP_LCD_TOUCH_MAX_POINTS > 1 && CONFIG_LVGL_PORT_ENABLE_GESTURES)
+    // Number of touch points which need to be constantly updated inside gesture recognizers
+#define GESTURE_TOUCH_POINTS 2
+
+    uint8_t touchpad_track_id[CONFIG_ESP_LCD_TOUCH_MAX_POINTS] = {0};
+
+    /* Read track IDs for TODO number of touch points*/
+    esp_err_t err =  esp_lcd_touch_get_track_id(touch_ctx->handle, touchpad_track_id, GESTURE_TOUCH_POINTS);
+
+    /* Initialize LVGL touch data for each activated touch point */
+    /* static */ lv_indev_touch_data_t touches[CONFIG_ESP_LCD_TOUCH_MAX_POINTS] = {0};
+    if (err != ESP_ERR_NOT_SUPPORTED) {
+        for (int i = 0; i < touchpad_cnt; i++) {
+            touches[i].state = LV_INDEV_STATE_PRESSED;
+            touches[i].point.x = touchpad_x[i];
+            touches[i].point.y = touchpad_y[i];
+            touches[i].id = touchpad_track_id[i];
+            touches[i].timestamp = esp_timer_get_time() / 1000;
+        }
+    }
+
+    /* Pass touch data to LVGL gesture recognizers */
+    lv_indev_gesture_recognizers_update(indev_drv, touches, GESTURE_TOUCH_POINTS);
+    lv_indev_gesture_recognizers_set_data(indev_drv, data);
+
+#endif
 
     if (touchpad_pressed && touchpad_cnt > 0) {
         data->point.x = touch_ctx->scale.x * touchpad_x[0];