[evolution] I#454 - [ECellCheckbox] Draw the check state using gtk+ theme

[Milan Crha <mcrha src gnome org>]

commit e6f810c3df6e061040c551f14cb9f88e5e52cd45
Author: Milan Crha <mcrha redhat com>
Date:   Fri May 24 12:42:17 2019 +0200

    I#454 - [ECellCheckbox] Draw the check state using gtk+ theme
    
    Closes https://gitlab.gnome.org/GNOME/evolution/issues/454

 src/e-util/e-cell-checkbox.c | 83 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 77 insertions(+), 6 deletions(-)
---
diff --git a/src/e-util/e-cell-checkbox.c b/src/e-util/e-cell-checkbox.c
index 501c0f15ac..d4ab4bac7c 100644
--- a/src/e-util/e-cell-checkbox.c
+++ b/src/e-util/e-cell-checkbox.c
@@ -34,8 +34,6 @@
 
 G_DEFINE_TYPE (ECellCheckbox, e_cell_checkbox, E_TYPE_CELL_TOGGLE)
 
-static GdkPixbuf *checks[2];
-
 static void
 ecc_print (ECellView *ecell_view,
            GtkPrintContext *context,
@@ -62,14 +60,87 @@ ecc_print (ECellView *ecell_view,
        cairo_restore (cr);
 }
 
+static void
+ecc_draw (ECellView *ecell_view,
+         cairo_t *cr,
+         gint model_col,
+         gint view_col,
+         gint row,
+         ECellFlags flags,
+         gint x1,
+         gint y1,
+         gint x2,
+         gint y2)
+{
+       GtkStyleContext *style_context;
+       GtkWidgetPath *widget_path;
+       gint xx, yy, ww, hh;
+       const gint value = GPOINTER_TO_INT (e_table_model_value_at (ecell_view->e_table_model, model_col, 
row));
+
+       if (value != 0 && value != 1)
+               return;
+
+       xx = x1;
+       yy = y1;
+       ww = x2 - x1;
+       hh = y2 - y1;
+
+       if (ww > 16) {
+               xx += (ww - 16) / 2;
+               ww = 16;
+       }
+
+       if (hh > 16) {
+               yy += (hh - 16) / 2;
+               hh = 16;
+       }
+
+       widget_path = gtk_widget_path_new ();
+       gtk_widget_path_append_type (widget_path, G_TYPE_NONE);
+       gtk_widget_path_iter_set_object_name (widget_path, -1, "check");
+
+       style_context = gtk_style_context_new ();
+       gtk_style_context_set_path (style_context, widget_path);
+       gtk_style_context_set_state (style_context,
+               (value ? GTK_STATE_FLAG_CHECKED : 0) |
+               ((flags & E_CELL_SELECTED) != 0 ? GTK_STATE_FLAG_SELECTED : 0));
+
+       gtk_render_frame (style_context, cr, xx, yy, ww, hh);
+       gtk_render_check (style_context, cr, xx, yy, ww, hh);
+
+       gtk_widget_path_unref (widget_path);
+       g_object_unref (style_context);
+}
+
 static void
 e_cell_checkbox_class_init (ECellCheckboxClass *class)
 {
        ECellClass *ecc = E_CELL_CLASS (class);
 
        ecc->print = ecc_print;
-       checks[0] = gdk_pixbuf_new_from_xpm_data (check_empty_xpm);
-       checks[1] = gdk_pixbuf_new_from_xpm_data (check_filled_xpm);
+       ecc->draw = ecc_draw;
+}
+
+static GdkPixbuf *
+ecc_get_check_singleton (gboolean the_empty)
+{
+       static GdkPixbuf *check_empty = NULL;
+       static GdkPixbuf *check_filled = NULL;
+       GdkPixbuf **pcheck;
+
+       if (the_empty)
+               pcheck = &check_empty;
+       else
+               pcheck = &check_filled;
+
+       if (*pcheck)
+               return g_object_ref (*pcheck);
+
+       *pcheck = gdk_pixbuf_new_from_xpm_data (the_empty ? check_empty_xpm : check_filled_xpm);
+
+       g_object_weak_ref (G_OBJECT (*pcheck), (GWeakNotify) g_nullify_pointer, pcheck);
+
+       return *pcheck;
 }
 
 static void
@@ -79,8 +150,8 @@ e_cell_checkbox_init (ECellCheckbox *eccb)
 
        pixbufs = e_cell_toggle_get_pixbufs (E_CELL_TOGGLE (eccb));
 
-       g_ptr_array_add (pixbufs, g_object_ref (checks[0]));
-       g_ptr_array_add (pixbufs, g_object_ref (checks[1]));
+       g_ptr_array_add (pixbufs, ecc_get_check_singleton (TRUE));
+       g_ptr_array_add (pixbufs, ecc_get_check_singleton (FALSE));
 }
 
 /**