year-view: Added visual clue for days with events

Year view didn't have hints for days with events and this feature was
requested to be added to gnome-calendar.

This is an old request but in the past gnome-design team though it would
be better to keep the layout simple without hints for days with events.
Now with the changes in gnome-shell calendar and in order to keep them
in sync, this feature was added to gnome-calendar.

In order to implement this code we had to add a few css styles and a
code to add a small circle below everyday with events. Although
gnome-shell calendar uses an svg image with a 3x3 dot, we chose to use a
pango function to draw the dot.

https://bugzilla.gnome.org/show_bug.cgi?id=743317

data/theme/gtk-styles.css

@@ -120,6 +120,19 @@ calendar-view.second-view-header {
     font-weight: bold;
 }
 
+.year-navigator.with-events {
+    background-color: @theme_fg_color;
+    border-radius: 3px;
+}
+
+.year-navigator.with-events-selected {
+    background-color: @theme_selected_bg_color;
+}
+
+.year-navigator.with-events-sunday {
+    background-color: alpha(@theme_fg_color, 0.5);
+}
+
 .sidebar-header {
     font-weight: bold;
     font-size: 11px;

src/gcal-year-view.c

@@ -28,6 +28,7 @@
 #define NAVIGATOR_CELL_WIDTH (210 + 15)
 #define NAVIGATOR_CELL_HEIGHT 210
 #define SIDEBAR_PREFERRED_WIDTH 200
+#define VISUAL_CLUES_SIDE 3.0
 
 typedef struct
 {
@@ -526,6 +527,8 @@ draw_month_grid (GcalYearView *year_view,
   gint days_delay, days, shown_rows, sunday_idx;
   gchar *str, *nr_day, *nr_week;
   gboolean selected_day;
+  GList *events;
+  icaltimetype start_date, end_date;
 
   cairo_save (cr);
   context = gtk_widget_get_style_context (widget);
@@ -590,6 +593,19 @@ draw_month_grid (GcalYearView *year_view,
   shown_rows = ceil (days / 7.0);
   sunday_idx = year_view->k * 6 + sw * ((7 - year_view->first_weekday) % 7);
 
+  start_date.day    = 1;
+  start_date.month  = month_nr + 1;
+  start_date.year   = year_view->date->year;
+  start_date.hour   = 0;
+  start_date.minute = 0;
+  start_date.second = 0;
+  end_date.day    = 1;
+  end_date.month  = month_nr + 1;
+  end_date.year   = year_view->date->year;
+  end_date.hour   = 23;
+  end_date.minute = 59;
+  end_date.second = 59;
+
   for (i = 0; i < 7 * shown_rows; i++)
     {
       column = i % 7;
@@ -695,6 +711,25 @@ draw_month_grid (GcalYearView *year_view,
                              layout);
         }
 
+      start_date.day = end_date.day = j;
+      events = gcal_manager_get_events (year_view->manager, &start_date, &end_date);
+      if (events != NULL)
+        {
+          gtk_style_context_save (context);
+          gtk_style_context_add_class (context, "with-events");
+          if (selected_day)
+            gtk_style_context_add_class (context, "with-events-selected");
+          else if (column == sunday_idx)
+            gtk_style_context_add_class (context, "with-events-sunday");
+          box_padding_start = (box_side - VISUAL_CLUES_SIDE) / 2 > 0 ? (box_side - VISUAL_CLUES_SIDE) / 2 : 0;
+          gtk_render_background (context, cr,
+                                 box_side * (column + 0.5 + year_view->k) + x + sw * box_padding_start - year_view->k * VISUAL_CLUES_SIDE,
+                                 box_side * (row + 1) + y + box_padding_top + layout_height + 2.0,
+                                 VISUAL_CLUES_SIDE, VISUAL_CLUES_SIDE);
+          gtk_style_context_restore (context);
+          g_list_free_full (events, g_free);
+        }
+
       g_free (nr_day);
     }
   pango_font_description_free (font_desc);