[gnome-calendar] year-view: add hover effect to the navigator

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 6a8a4dfad014d8933a94c70d6de5d946e8928f88
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Fri May 20 22:09:00 2016 -0300

    year-view: add hover effect to the navigator
    
    The current implementation of the Year navigator gives
    absolutely no clue that the days are actually selectable,
    which may confuse some users.
    
    A simple way to inform the user that the Year navigator
    is actually interactive is the hovering effect.
    
    Fix the lack of feedback by adding the hover effect to the
    year navigator.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762462

 data/theme/gtk-styles.css |    5 +++
 src/gcal-year-view.c      |   70 +++++++++++++++++++++++++++++++++++---------
 2 files changed, 60 insertions(+), 15 deletions(-)
---
diff --git a/data/theme/gtk-styles.css b/data/theme/gtk-styles.css
index c7f07f9..0222bce 100644
--- a/data/theme/gtk-styles.css
+++ b/data/theme/gtk-styles.css
@@ -122,6 +122,11 @@ calendar-view.second-view-header {
     font-weight: bold;
 }
 
+.year-navigator:hover {
+    background-color: alpha(@theme_fg_color, 0.1);
+    border-radius: 2px;
+}
+
 .year-navigator.with-events {
     background-color: @theme_fg_color;
     border-radius: 3px;
diff --git a/src/gcal-year-view.c b/src/gcal-year-view.c
index 74e97eb..abb9533 100644
--- a/src/gcal-year-view.c
+++ b/src/gcal-year-view.c
@@ -34,6 +34,7 @@ typedef struct
   /* month span from 0 to 11 */
   gint start_day, start_month;
   gint end_day, end_month;
+  gint hovered_day, hovered_month;
 } ButtonData;
 
 typedef struct
@@ -729,6 +730,27 @@ draw_month_grid (GcalYearView *year_view,
       box_padding_top = (box_side - layout_height) / 2 > 0 ? (box_side - layout_height) / 2 : 0;
       box_padding_start = (box_side - layout_width) / 2 > 0 ? (box_side - layout_width) / 2 : 0;
 
+      /* Draw the hover background */
+      if (year_view->selected_data->hovered_day == j &&
+          year_view->selected_data->hovered_month == month_nr)
+        {
+          gint hover_x, hover_y;
+
+          hover_x = box_side * column + x + sw * box_padding_start / 2.0 - year_view->k * box_side - 2.0;
+          hover_y = box_side * (row + 1) + y + box_padding_top - 1.0;
+
+          gtk_style_context_set_state (context, state_flags | GTK_STATE_FLAG_PRELIGHT);
+
+          gtk_render_background (context,
+                                 cr,
+                                 hover_x,
+                                 hover_y,
+                                 box_side - box_padding_start / 2.0,
+                                 box_side);
+
+          gtk_style_context_set_state (context, state_flags);
+        }
+
       selected_day = FALSE;
       if (year_view->selected_data->start_day != 0)
         {
@@ -1054,25 +1076,43 @@ navigator_motion_notify_cb (GcalYearView   *year_view,
   gint day, month;
   gboolean is_title = FALSE;
 
-  if (!year_view->button_pressed)
-    return FALSE;
+  if (calculate_day_month_for_coord (year_view, event->x, event->y, &day, &month, &is_title))
+    {
+      if (year_view->button_pressed)
+        {
+          /* Cancel the hover when selecting a date range */
+          year_view->selected_data->hovered_day = -1;
+          year_view->selected_data->hovered_month = -1;
 
-  if (!calculate_day_month_for_coord (year_view, event->x, event->y, &day, &month, &is_title))
-    goto fail;
+          if (is_title)
+            day = g_date_get_days_in_month (month + 1, year_view->date->year);
 
-  if (is_title)
-    day = g_date_get_days_in_month (month + 1, year_view->date->year);
+          year_view->selected_data->end_day = day;
+          year_view->selected_data->end_month = month;
+          gtk_widget_queue_draw (widget);
 
-  year_view->selected_data->end_day = day;
-  year_view->selected_data->end_month = month;
-  gtk_widget_queue_draw (widget);
-  return TRUE;
+          return GDK_EVENT_STOP;
+        }
+      else
+        {
+          /* We only deal with the hover effect when the button is not pressed */
+          year_view->selected_data->hovered_day = day;
+          year_view->selected_data->hovered_month = month;
+          gtk_widget_queue_draw (widget);
 
-fail:
-  year_view->selected_data->end_day = year_view->selected_data->start_day;
-  year_view->selected_data->end_month = year_view->selected_data->start_month;
-  gtk_widget_queue_draw (widget);
-  return TRUE;
+          return GDK_EVENT_PROPAGATE;
+        }
+    }
+  else
+    {
+      /* Reset the end day */
+      year_view->selected_data->end_day = year_view->selected_data->start_day;
+      year_view->selected_data->end_month = year_view->selected_data->start_month;
+
+      gtk_widget_queue_draw (widget);
+
+      return GDK_EVENT_STOP;
+    }
 }
 
 static void