From 39d03a80f45847a1977cfe9cc6a509b1613d0aca Mon Sep 17 00:00:00 2001
From: Gabor Kiss-Vamosi <kisvegabor@gmail.com>
Date: Wed, 16 Nov 2022 11:32:00 +0100
Subject: [PATCH] feat(table): scroll to the selected cell with key navigation

Fixes https://forum.lvgl.io/t/grid-navigation-with-automatic-scrolling-for-table/10285
---
 src/widgets/lv_table.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/widgets/lv_table.c b/src/widgets/lv_table.c
index 5ff65ab23..8adba1310 100644
--- a/src/widgets/lv_table.c
+++ b/src/widgets/lv_table.c
@@ -42,6 +42,7 @@ static lv_res_t get_pressed_cell(lv_obj_t * obj, uint16_t * row, uint16_t * col)
 static size_t get_cell_txt_len(const char * txt);
 static void copy_cell_txt(char * dst, const char * txt);
 static void get_cell_area(lv_obj_t * obj, uint16_t row, uint16_t col, lv_area_t * area);
+static void scroll_to_selected_cell(lv_obj_t * obj);
 
 static inline bool is_cell_empty(void * cell)
 {
@@ -516,6 +517,7 @@ static void lv_table_event(const lv_obj_class_t * class_p, lv_event_t * e)
         if(col == LV_TABLE_CELL_NONE || row == LV_TABLE_CELL_NONE) {
             table->col_act = 0;
             table->row_act = 0;
+            scroll_to_selected_cell(obj);
             lv_obj_invalidate(obj);
             return;
         }
@@ -560,6 +562,8 @@ static void lv_table_event(const lv_obj_class_t * class_p, lv_event_t * e)
             table->row_act = row;
             lv_obj_invalidate(obj);
 
+            scroll_to_selected_cell(obj);
+
             res = lv_event_send(obj, LV_EVENT_VALUE_CHANGED, NULL);
             if(res != LV_RES_OK) return;
         }
@@ -1004,4 +1008,26 @@ static void get_cell_area(lv_obj_t * obj, uint16_t row, uint16_t col, lv_area_t
 
 }
 
+
+static void scroll_to_selected_cell(lv_obj_t * obj)
+{
+    lv_table_t * table = (lv_table_t *)obj;
+
+    lv_area_t a;
+    get_cell_area(obj, table->row_act, table->col_act, &a);
+    if(a.x1 < 0) {
+        lv_obj_scroll_by_bounded(obj, -a.x1, 0, LV_ANIM_ON);
+    }
+    else if(a.x2 > lv_obj_get_width(obj)) {
+        lv_obj_scroll_by_bounded(obj, lv_obj_get_width(obj) - a.x2, 0, LV_ANIM_ON);
+    }
+
+    if(a.y1 < 0) {
+        lv_obj_scroll_by_bounded(obj, 0, -a.y1, LV_ANIM_ON);
+    }
+    else if(a.y2 > lv_obj_get_height(obj)) {
+        lv_obj_scroll_by_bounded(obj, 0, lv_obj_get_height(obj) - a.y2 , LV_ANIM_ON);
+    }
+
+}
 #endif