Draw tree view rows in alternating colours ('zebra stripes')

NOTE:

Please see the README and the file `data/zebra-stripes.css` for information
on how to actually activate the zebra stripes.

1 files changed, 170 insertions, 0 deletions

diff --git a/patches/treeview-zebra-stripes.c b/patches/treeview-zebra-stripes.c
new file mode 100644
index 0000000..8dafa16
--- /dev/null
+++ b/patches/treeview-zebra-stripes.c
@@ -0,0 +1,170 @@
+/* Treeview Zebra Stripes:
+ * (based on gtk3-classic patch 'treeview__alternating_row_colours.patch'):
+ *
+ * Adds appropriate style classes to each cell in a GtkTreeView, so that themes
+ * can draw the rows of a treeview in alternating colours, also known as
+ * 'zebra stripes'.
+ */
+
+
+#include <gtk/gtk.h>
+#include <gdk/gdk.h>
+#include <glib.h>
+#include <cairo/cairo.h>
+
+#include <gtk3-classic.h>
+
+
+#undef  G_LOG_DOMAIN
+#define G_LOG_DOMAIN	"Gtk3-Classic::Treeview-Zebra-Stripes"
+
+
+static gboolean	find_row_index	(GtkTreeView *	treeview,
+				 GtkTreeModel *	model,
+				 GtkTreeIter *	start_iter,
+				 GtkTreePath *	target_path,
+				 int *		index);
+
+
+INTERCEPTED_CLASS_METHOD (gtk_cell_area, render,
+			  (GtkCellArea *	area,
+			   GtkCellAreaContext *	context,
+			   GtkWidget *		widget,
+			   cairo_t *		cr,
+			   const GdkRectangle *	background_area,
+			   const GdkRectangle *	cell_area,
+			   GtkCellRendererState	flags,
+			   gboolean		paint_focus),
+			  void)
+
+
+void treeview_zebra_stripes_init ()
+{
+	GtkCellAreaClass * gtk_cell_area_class =
+	 g_type_class_ref (GTK_TYPE_CELL_AREA);
+
+	INTERCEPT_CLASS_METHOD (gtk_cell_area, GTK_CELL_AREA_CLASS,
+				render)
+
+	g_type_class_unref (gtk_cell_area_class);
+}
+
+
+static void
+new_gtk_cell_area_render
+(GtkCellArea *		area,
+ GtkCellAreaContext *	context,
+ GtkWidget *		widget,
+ cairo_t *		cr,
+ const GdkRectangle *	background_area,
+ const GdkRectangle *	cell_area,
+ GtkCellRendererState	flags,
+ gboolean		paint_focus)
+{
+	GtkTreeView *		treeview;
+	GtkTreeModel *		model;
+	GtkStyleContext *	style;
+	gint			bin_x, bin_y;
+	GtkTreePath *		path;
+	int			index;
+	GtkTreeViewColumn *	column;
+	GList *			columns;
+
+
+	if (GTK_IS_TREE_VIEW (widget))
+	{
+		treeview = GTK_TREE_VIEW (widget);
+		model = gtk_tree_view_get_model (treeview);
+		style = gtk_widget_get_style_context (widget);
+		columns = gtk_tree_view_get_columns (treeview);
+
+		bin_x = cell_area->x + cell_area->width - 1;
+		bin_y = cell_area->y + cell_area->height - 1;
+
+		gtk_tree_view_get_path_at_pos (treeview, bin_x, bin_y,
+					       &path, &column, NULL, NULL);
+		if (path != NULL)
+		{
+			index = 0;
+			find_row_index (treeview, model, NULL, path, &index);
+			gtk_tree_path_free (path);
+			gtk_style_context_add_class (style,
+			  ((index % 2) ? "even" : "odd"));
+		}
+
+		if (column == columns->data)
+			gtk_style_context_add_class (style, "first");
+		if (column == g_list_last (columns)->data)
+			gtk_style_context_add_class (style, "last");
+		if ((flags & GTK_CELL_RENDERER_SORTED))
+			gtk_style_context_add_class (style, "sorted");
+
+		gtk_render_background (style, cr,
+				       background_area->x, background_area->y,
+				       background_area->width,
+				       background_area->height);
+	}
+
+
+	CALL_ORIGINAL_CLASS_METHOD (gtk_cell_area, render,
+				    (area, context, widget, cr,
+				     background_area, cell_area,
+				     flags, paint_focus));
+}
+
+
+/* Helper functions */
+
+static gboolean
+find_row_index
+(GtkTreeView *	treeview,
+ GtkTreeModel *	model,
+ GtkTreeIter *	start_iter,
+ GtkTreePath *	target_path,
+ int *		index)
+{
+	GtkTreeIter	iter;
+	GtkTreeIter	child_iter;
+	GtkTreePath *	path;
+
+
+	if (start_iter == NULL)
+	{
+		if (! gtk_tree_model_get_iter_first (model, &iter))
+			return TRUE;
+	}
+	else
+		iter = *start_iter;
+
+	while (1)
+	{
+		path = gtk_tree_model_get_path (model, &iter);
+
+		if (gtk_tree_path_compare (path, target_path) == 0)
+		{
+			gtk_tree_path_free (path);
+			return TRUE;
+		}
+
+		if (gtk_tree_view_row_expanded (treeview, path))
+		{
+			(*index)++;
+			gtk_tree_model_iter_children (model, &child_iter, &iter);
+			if (find_row_index (treeview, model, &child_iter,
+					    target_path, index))
+			{
+				gtk_tree_path_free (path);
+				return TRUE;
+			}
+		}
+
+		gtk_tree_path_free (path);
+		if (! gtk_tree_model_iter_next (model, &iter))
+			break;
+		else
+			(*index)++;
+	}
+
+
+	return FALSE;
+}