diff --git a/src/lv_draw/lv_draw_mask.c b/src/lv_draw/lv_draw_mask.c
index e6492d713..384bf0d28 100644
--- a/src/lv_draw/lv_draw_mask.c
+++ b/src/lv_draw/lv_draw_mask.c
@@ -382,7 +382,7 @@ void lv_draw_mask_radius_init(lv_draw_mask_radius_param_t * param, const lv_area
  * @param opa_bottom opacity at the bottom
  * @param y_bottom at which coordinate reach `opa_bottom`.
  */
-void lv_draw_mask_fade_init(lv_draw_mask_fade_param_t * param, lv_area_t * coords, lv_opa_t opa_top, lv_coord_t y_top,
+void lv_draw_mask_fade_init(lv_draw_mask_fade_param_t * param, const lv_area_t * coords, lv_opa_t opa_top, lv_coord_t y_top,
                             lv_opa_t opa_bottom, lv_coord_t y_bottom)
 {
     lv_area_copy(&param->cfg.coords, coords);
@@ -401,7 +401,7 @@ void lv_draw_mask_fade_init(lv_draw_mask_fade_param_t * param, lv_area_t * coord
  * @param coords coordinates of the map (absolute coordinates)
  * @param map array of bytes with the mask values
  */
-void lv_draw_mask_map_init(lv_draw_mask_map_param_t * param, lv_area_t * coords, const lv_opa_t * map)
+void lv_draw_mask_map_init(lv_draw_mask_map_param_t * param, const lv_area_t * coords, const lv_opa_t * map)
 {
     lv_area_copy(&param->cfg.coords, coords);
     param->cfg.map = map;
diff --git a/src/lv_draw/lv_draw_mask.h b/src/lv_draw/lv_draw_mask.h
index 6c36c6480..ccacb5242 100644
--- a/src/lv_draw/lv_draw_mask.h
+++ b/src/lv_draw/lv_draw_mask.h
@@ -257,7 +257,7 @@ void lv_draw_mask_radius_init(lv_draw_mask_radius_param_t * param, const lv_area
  * @param opa_bottom opacity at the bottom
  * @param y_bottom at which coordinate reach `opa_bottom`.
  */
-void lv_draw_mask_fade_init(lv_draw_mask_fade_param_t * param, lv_area_t * coords, lv_opa_t opa_top, lv_coord_t y_top,
+void lv_draw_mask_fade_init(lv_draw_mask_fade_param_t * param, const lv_area_t * coords, lv_opa_t opa_top, lv_coord_t y_top,
                             lv_opa_t opa_bottom, lv_coord_t y_bottom);
 
 /**
@@ -266,7 +266,7 @@ void lv_draw_mask_fade_init(lv_draw_mask_fade_param_t * param, lv_area_t * coord
  * @param coords coordinates of the map (absolute coordinates)
  * @param map array of bytes with the mask values
  */
-void lv_draw_mask_map_init(lv_draw_mask_map_param_t * param, lv_area_t * coords, const lv_opa_t * map);
+void lv_draw_mask_map_init(lv_draw_mask_map_param_t * param, const lv_area_t * coords, const lv_opa_t * map);
 
 /**********************
  *      MACROS
diff --git a/src/lv_widgets/lv_chart.c b/src/lv_widgets/lv_chart.c
index 34533d63a..087bbc58e 100644
--- a/src/lv_widgets/lv_chart.c
+++ b/src/lv_widgets/lv_chart.c
@@ -803,8 +803,8 @@ static void draw_series_line(lv_obj_t * chart, const lv_area_t * series_area, co
 
         has_fade = area_dsc.bg_grad_dir == LV_GRAD_DIR_VER ? true : false;
         if(has_fade) {
-            lv_draw_mask_fade_init(&mask_fade_p, &chart->coords, area_dsc.bg_main_color_stop, chart->coords.y1,
-                                   area_dsc.bg_grad_color_stop, chart->coords.y2);
+            lv_draw_mask_fade_init(&mask_fade_p, series_area, area_dsc.bg_main_color_stop, series_area->y1,
+                                   area_dsc.bg_grad_color_stop, series_area->y2);
         }
     }