elm_spinner: add feature in spinner to change values while dragging relative to the speed of dragging

Summary:
Currently the values in spinner change while dragging only based on
the amount of pixels dragged, this patch will enable Spinner to change value
based on the speed of dragging so that it will be more user friendly. This
will help users to alter drag values by big amounts if dragged in a good speed.

Test Plan: test_spinner.c in elementary_test

Reviewers: raster, prince.dubey, shilpasingh, cedric

Reviewed By: cedric

Subscribers: poornima.srinivasan, rajeshps, govi

Differential Revision: https://phab.enlightenment.org/D2659

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>

legacy/elementary/AUTHORS

@@ -164,3 +164,4 @@ Jee-Yong Um <conr2d@gmail.com>
 Ji-In Moon <jiin.moon@samsung.com> 
 Subodh Kumar <s7158.kumar@samsung.com>
 Kumar Navneet <k.navneet@samsung.com>
+Godly T Alias <godly.talias@samsung.com>

legacy/elementary/src/bin/test_spinner.c

@@ -35,7 +35,7 @@ test_spinner(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED, void *event_i
    elm_spinner_label_format_set(sp, "%1.1f units");
    elm_spinner_step_set(sp, 1.3);
    elm_spinner_wrap_set(sp, EINA_TRUE);
-   elm_spinner_min_max_set(sp, -50.0, 250.0);
+   elm_spinner_min_max_set(sp, -5000.0, 5000.0);
    evas_object_size_hint_align_set(sp, EVAS_HINT_FILL, 0.5);
    evas_object_size_hint_weight_set(sp, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
    evas_object_smart_callback_add(sp, "spinner,drag,start",

legacy/elementary/src/lib/elm_authors.h

@@ -162,6 +162,7 @@
  * @author yinsc <shouchen.yin@@samsung.com>
  * @author Subodh Kumar <s7158.kumar@@samsung.com>
  * @author Kumar Navneet <k.navneet@@samsung.com>
+ * @author Godly T Alias <godly.talias@@samsung.com>
  *
  * Please contact <enlightenment-devel@lists.sourceforge.net> to get in
  * contact with the developers and maintainers.

legacy/elementary/src/lib/elm_spinner.c

@@ -217,11 +217,18 @@ _drag_cb(void *data,
    else
      eo_do((Eo *)wd->resize_obj,
            edje_obj_part_drag_value_get("elm.dragable.slider", &pos, NULL));
+   if (sd->drag_prev_pos != 0)
+     sd->drag_val_step = pow((pos - sd->drag_prev_pos), 2);
+   else
+     sd->drag_val_step = 1;
 
-   delta = pos * sd->step * _elm_config->scale;
+
+   delta = sd->drag_val_step * sd->step * _elm_config->scale;
+   if (pos < sd->drag_prev_pos) delta *= -1;
+   sd->drag_prev_pos = pos;
    /* If we are on rtl mode, change the delta to be negative on such changes */
    if (elm_widget_mirrored_get(obj)) delta *= -1;
-   if (_value_set(data, sd->drag_start_val + delta)) _label_write(data);
+   if (_value_set(data, sd->val + delta)) _label_write(data);
    sd->dragging = 1;
 }
 
@@ -233,7 +240,8 @@ _drag_start_cb(void *data,
 {
    ELM_SPINNER_DATA_GET(data, sd);
 
-   sd->drag_start_val = sd->val;
+   sd->drag_prev_pos = 0;
+   sd->drag_val_step = 1;
 
    evas_object_smart_callback_call(obj, SIG_DRAG_START, NULL);
 }
@@ -247,7 +255,8 @@ _drag_stop_cb(void *data,
    ELM_SPINNER_DATA_GET(data, sd);
    ELM_WIDGET_DATA_GET_OR_RETURN(data, wd);
 
-   sd->drag_start_val = 0;
+   sd->drag_prev_pos = 0;
+   sd->drag_val_step = 1;
    edje_object_part_drag_value_set
      (wd->resize_obj, "elm.dragable.slider", 0.0, 0.0);
 

legacy/elementary/src/lib/elm_widget_spinner.h

@@ -32,8 +32,7 @@ struct _Elm_Spinner_Data
    const char           *label;
    double                val, val_min, val_max, val_base;
    double                step; /**< step for the value change. 1 by default. */
-   double                drag_start_val; /**< spinner value on drag start.
+   double                drag_prev_pos, drag_val_step;
-                                         this is reset to 0 when drag stops. */
    double                spin_speed, interval, first_interval;
    int                   round;
    Ecore_Timer          *delay_change_timer; /**< a timer for a delay,changed smart callback */