[evolution] Bug 764542 - ECalendar next/previous month arrows oversized in gtk+ 3.20

[Milan Crha <mcrha src gnome org>]

commit afb752ef81a16e4221d083906b4d5d38c9332c9f
Author: Milan Crha <mcrha redhat com>
Date:   Mon Apr 4 17:19:37 2016 +0200

    Bug 764542 - ECalendar next/previous month arrows oversized in gtk+ 3.20

 e-util/e-calendar.c |   78 ++++++++++++++++++++++++++++++++-------------------
 1 files changed, 49 insertions(+), 29 deletions(-)
---
diff --git a/e-util/e-calendar.c b/e-util/e-calendar.c
index b28c191..9579d67 100644
--- a/e-util/e-calendar.c
+++ b/e-util/e-calendar.c
@@ -124,6 +124,50 @@ calitem_month_width_changed_cb (ECalendarItem *item,
        gtk_widget_queue_resize (GTK_WIDGET (cal));
 }
 
+static GtkWidget *
+e_calendar_create_button (GtkArrowType arrow_type)
+{
+       GtkWidget *button, *pixmap;
+
+       button = gtk_button_new ();
+       gtk_button_set_relief (GTK_BUTTON (button), GTK_RELIEF_NONE);
+       gtk_widget_show (button);
+
+       pixmap = gtk_arrow_new (arrow_type, GTK_SHADOW_NONE);
+       gtk_widget_show (pixmap);
+       gtk_container_add (GTK_CONTAINER (button), pixmap);
+
+       #if GTK_CHECK_VERSION (3, 20, 0)
+       {
+               GtkCssProvider *css_provider;
+               GtkStyleContext *style_context;
+               GError *error = NULL;
+
+               css_provider = gtk_css_provider_new ();
+               gtk_css_provider_load_from_data (css_provider,
+                       "button.ecalendar {"
+                       " min-height: 0px;"
+                       " min-width: 0px;"
+                       " padding: 0px;"
+                       "}", -1, &error);
+               style_context = gtk_widget_get_style_context (button);
+               if (error == NULL) {
+                       gtk_style_context_add_class (style_context, "ecalendar");
+                       gtk_style_context_add_provider (
+                               style_context,
+                               GTK_STYLE_PROVIDER (css_provider),
+                               GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+               } else {
+                       g_warning ("%s: %s", G_STRFUNC, error->message);
+                       g_clear_error (&error);
+               }
+               g_object_unref (css_provider);
+       }
+       #endif
+
+       return button;
+}
+
 static void
 e_calendar_class_init (ECalendarClass *class)
 {
@@ -151,7 +195,7 @@ e_calendar_init (ECalendar *cal)
        GnomeCanvasGroup *canvas_group;
        PangoFontDescription *small_font_desc;
        PangoContext *pango_context;
-       GtkWidget *button, *pixmap;
+       GtkWidget *button;
        AtkObject *a11y;
 
        pango_context = gtk_widget_create_pango_context (GTK_WIDGET (cal));
@@ -181,9 +225,7 @@ e_calendar_init (ECalendar *cal)
                G_CALLBACK (calitem_month_width_changed_cb), cal);
 
        /* Create the arrow buttons to move to the previous/next month. */
-       button = gtk_button_new ();
-       gtk_button_set_relief (GTK_BUTTON (button), GTK_RELIEF_NONE);
-       gtk_widget_show (button);
+       button = e_calendar_create_button (GTK_ARROW_LEFT);
        g_signal_connect_swapped (
                button, "pressed",
                G_CALLBACK (e_calendar_on_prev_pressed), cal);
@@ -194,10 +236,6 @@ e_calendar_init (ECalendar *cal)
                button, "clicked",
                G_CALLBACK (e_calendar_on_prev_clicked), cal);
 
-       pixmap = gtk_arrow_new (GTK_ARROW_LEFT, GTK_SHADOW_NONE);
-       gtk_widget_show (pixmap);
-       gtk_container_add (GTK_CONTAINER (button), pixmap);
-
        cal->prev_item = gnome_canvas_item_new (
                canvas_group,
                gnome_canvas_widget_get_type (),
@@ -206,9 +244,7 @@ e_calendar_init (ECalendar *cal)
        a11y = gtk_widget_get_accessible (button);
        atk_object_set_name (a11y, _("Previous month"));
 
-       button = gtk_button_new ();
-       gtk_button_set_relief (GTK_BUTTON (button), GTK_RELIEF_NONE);
-       gtk_widget_show (button);
+       button = e_calendar_create_button (GTK_ARROW_RIGHT);
        g_signal_connect_swapped (
                button, "pressed",
                G_CALLBACK (e_calendar_on_next_pressed), cal);
@@ -219,10 +255,6 @@ e_calendar_init (ECalendar *cal)
                button, "clicked",
                G_CALLBACK (e_calendar_on_next_clicked), cal);
 
-       pixmap = gtk_arrow_new (GTK_ARROW_RIGHT, GTK_SHADOW_NONE);
-       gtk_widget_show (pixmap);
-       gtk_container_add (GTK_CONTAINER (button), pixmap);
-
        cal->next_item = gnome_canvas_item_new (
                canvas_group,
                gnome_canvas_widget_get_type (),
@@ -232,9 +264,7 @@ e_calendar_init (ECalendar *cal)
        atk_object_set_name (a11y, _("Next month"));
 
        /* Create the arrow buttons to move to the previous/next year. */
-       button = gtk_button_new ();
-       gtk_button_set_relief (GTK_BUTTON (button), GTK_RELIEF_NONE);
-       gtk_widget_show (button);
+       button = e_calendar_create_button (GTK_ARROW_LEFT);
        g_signal_connect_swapped (
                button, "pressed",
                G_CALLBACK (e_calendar_on_prev_year_pressed), cal);
@@ -245,10 +275,6 @@ e_calendar_init (ECalendar *cal)
                button, "clicked",
                G_CALLBACK (e_calendar_on_prev_year_clicked), cal);
 
-       pixmap = gtk_arrow_new (GTK_ARROW_LEFT, GTK_SHADOW_NONE);
-       gtk_widget_show (pixmap);
-       gtk_container_add (GTK_CONTAINER (button), pixmap);
-
        cal->prev_item_year = gnome_canvas_item_new (
                canvas_group,
                gnome_canvas_widget_get_type (),
@@ -257,9 +283,7 @@ e_calendar_init (ECalendar *cal)
        a11y = gtk_widget_get_accessible (button);
        atk_object_set_name (a11y, _("Previous year"));
 
-       button = gtk_button_new ();
-       gtk_button_set_relief (GTK_BUTTON (button), GTK_RELIEF_NONE);
-       gtk_widget_show (button);
+       button = e_calendar_create_button (GTK_ARROW_RIGHT);
        g_signal_connect_swapped (
                button, "pressed",
                G_CALLBACK (e_calendar_on_next_year_pressed), cal);
@@ -270,10 +294,6 @@ e_calendar_init (ECalendar *cal)
                button, "clicked",
                G_CALLBACK (e_calendar_on_next_year_clicked), cal);
 
-       pixmap = gtk_arrow_new (GTK_ARROW_RIGHT, GTK_SHADOW_NONE);
-       gtk_widget_show (pixmap);
-       gtk_container_add (GTK_CONTAINER (button), pixmap);
-
        cal->next_item_year = gnome_canvas_item_new (
                canvas_group,
                gnome_canvas_widget_get_type (),