fix(slider): adjusting the left knob too with encoder

https://forum.lvgl.io/t/slider-with-2-knobs-and-encoder-functionality/3770

CHANGELOG.md

@@ -16,6 +16,7 @@
 - fix(value_str) support Arabic letter connections in value string property
 - fix(indev) in LV_INDEV_TYPE_BUTTON recognize 1 cycle long presses too
 - fix(arc) make arc work with encoder
+- fix(slider) adjusting the left knob too with encoder
 
 ## v7.7.2 (17.11.2020)
 ### Bugfixes

src/lv_widgets/lv_bar.c

@@ -157,9 +157,11 @@ void lv_bar_set_value(lv_obj_t * bar, int16_t value, lv_anim_enable_t anim)
     lv_bar_ext_t * ext = lv_obj_get_ext_attr(bar);
     if(ext->cur_value == value) return;
 
-    int16_t new_value;
+    int16_t new_value = value;
-    new_value = value > ext->max_value ? ext->max_value : value;
+    new_value = value > ext->max_value ? ext->max_value : new_value;
     new_value = new_value < ext->min_value ? ext->min_value : new_value;
+    new_value = new_value < ext->start_value ? ext->start_value : new_value;
+
 
     if(ext->cur_value == new_value) return;
 #if LV_USE_ANIMATION == 0
@@ -184,9 +186,10 @@ void lv_bar_set_start_value(lv_obj_t * bar, int16_t start_value, lv_anim_enable_
     lv_bar_ext_t * ext = lv_obj_get_ext_attr(bar);
     if(ext->start_value == start_value) return;
 
-    int16_t new_value;
+    int16_t new_value = start_value;
-    new_value = start_value > ext->max_value ? ext->max_value : start_value;
+    new_value = new_value > ext->max_value ? ext->max_value : new_value;
-    new_value = new_value < ext->min_value ? ext->min_value : start_value;
+    new_value = new_value < ext->min_value ? ext->min_value : new_value;
+    new_value = new_value > ext->cur_value ? ext->cur_value : new_value;
 
     if(ext->start_value == new_value) return;
 #if LV_USE_ANIMATION == 0

src/lv_widgets/lv_slider.c

@@ -81,6 +81,7 @@ lv_obj_t * lv_slider_create(lv_obj_t * par, const lv_obj_t * copy)
     /*Initialize the allocated 'ext' */
     ext->value_to_set = NULL;
     ext->dragging = 0;
+    ext->right_knob_focus = 0;
     lv_style_list_init(&ext->style_knob);
 
     /*The signal and design functions are not copied so set them here*/
@@ -390,11 +391,20 @@ static lv_res_t lv_slider_signal(lv_obj_t * slider, lv_signal_t sign, void * par
         bool editing               = lv_group_get_editing(g);
         lv_indev_type_t indev_type = lv_indev_get_type(lv_indev_get_act());
         if(indev_type == LV_INDEV_TYPE_ENCODER) {
-            if(editing) lv_group_set_editing(g, false);
+            if(editing) {
+                if(ext->right_knob_focus == 0) ext->right_knob_focus = 1;
+                else {
+                    ext->right_knob_focus = 0;
+                    lv_group_set_editing(g, false);
+                }
+            }
         }
 #endif
 
     }
+    else if(sign == LV_SIGNAL_FOCUS) {
+        ext->right_knob_focus = 0;
+    }
     else if(sign == LV_SIGNAL_COORD_CHG) {
         /* The knob size depends on slider size.
          * During the drawing method the ext. size is used by the knob so refresh the ext. size.*/
@@ -425,12 +435,16 @@ static lv_res_t lv_slider_signal(lv_obj_t * slider, lv_signal_t sign, void * par
         char c = *((char *)param);
 
         if(c == LV_KEY_RIGHT || c == LV_KEY_UP) {
-            lv_slider_set_value(slider, lv_slider_get_value(slider) + 1, LV_ANIM_ON);
+            if(ext->right_knob_focus) lv_slider_set_value(slider, lv_slider_get_value(slider) + 1, LV_ANIM_ON);
+            else lv_slider_set_left_value(slider, lv_slider_get_left_value(slider) + 1, LV_ANIM_ON);
+
             res = lv_event_send(slider, LV_EVENT_VALUE_CHANGED, NULL);
             if(res != LV_RES_OK) return res;
         }
         else if(c == LV_KEY_LEFT || c == LV_KEY_DOWN) {
-            lv_slider_set_value(slider, lv_slider_get_value(slider) - 1, LV_ANIM_ON);
+            if(ext->right_knob_focus) lv_slider_set_value(slider, lv_slider_get_value(slider) - 1, LV_ANIM_ON);
+            else lv_slider_set_left_value(slider, lv_slider_get_left_value(slider) - 1, LV_ANIM_ON);
+
             res = lv_event_send(slider, LV_EVENT_VALUE_CHANGED, NULL);
             if(res != LV_RES_OK) return res;
         }

src/lv_widgets/lv_slider.h

@@ -49,6 +49,7 @@ typedef struct {
     lv_area_t right_knob_area;
     int16_t * value_to_set; /* Which bar value to set */
     uint8_t dragging : 1;       /*1: the slider is being dragged*/
+    uint8_t right_knob_focus :1;  /*1: with encoder now the right knob can be adjusted*/
 } lv_slider_ext_t;
 
 /** Built-in styles of slider*/