3 files changed, 44 insertions, 9 deletions

diff --git a/navit/command.c b/navit/command.c
index 8594aa851..68e64d309 100644
--- a/navit/command.c
+++ b/navit/command.c
@@ -112,7 +112,7 @@ command_attr_type(struct result *res)
 }
 
 static int
-command_object_get_attr(struct attr *object, enum attr_type attr_type, struct attr *ret)
+command_object_get_attr(struct context *ctx, struct attr *object, enum attr_type attr_type, struct attr *ret)
 {
 	struct object_func *func=object_func_lookup(object->type);
 	if (!func || !func->get_attr)
@@ -125,7 +125,7 @@ command_get_attr(struct context *ctx, struct result *res)
 {
 	int result;
 	enum attr_type attr_type=command_attr_type(res);
-	result=command_object_get_attr(&res->attr, attr_type, &res->attr);
+	result=command_object_get_attr(ctx, &res->attr, attr_type, &res->attr);
 	if (result) {
 		res->var=res->attrn;
 		res->varlen=res->attrnlen;
@@ -314,7 +314,7 @@ command_call_function(struct context *ctx, struct result *res)
 		ctx->error=missing_closing_brace;
 		return;
 	}
-	if (command_object_get_attr(&res->attr, attr_callback_list, &cbl)) {
+	if (command_object_get_attr(ctx, &res->attr, attr_callback_list, &cbl)) {
 		int valid;
 		dbg(0,"function call %s from %s\n",function, attr_to_name(res->attr.type));
 		callback_list_call_attr_4(cbl.u.callback_list, attr_command, function, list, NULL, &valid);
@@ -663,16 +663,34 @@ command_evaluate_to_string(struct attr *attr, char *expr, int **error)
 	char *ret;
 
 	command_evaluate_to(attr, expr, &ctx, &res);
-	if (error)
-		*error=ctx.error;
 	if (!ctx.error)
 		ret=get_string(&ctx, &res);
+	if (error)
+		*error=ctx.error;
 	if (ctx.error)
 		return NULL;
 	else
 		return ret;
 }
 
+int
+command_evaluate_to_int(struct attr *attr, char *expr, int **error)
+{
+	struct result res;
+	struct context ctx;
+	char *ret;
+
+	command_evaluate_to(attr, expr, &ctx, &res);
+	if (!ctx.error)
+		ret=get_int(&ctx, &res);
+	if (error)
+		*error=ctx.error;
+	if (ctx.error)
+		return 0;
+	else
+		return ret;
+}
+
 void
 command_evaluate(struct attr *attr, char *expr)
 {
diff --git a/navit/osd.c b/navit/osd.c
index f18abe652..4df2126df 100644
--- a/navit/osd.c
+++ b/navit/osd.c
@@ -147,6 +147,10 @@ osd_set_std_attr(struct attr **attrs, struct osd_item *item, int flags)
 	if (attr)
 		item->osd_configuration = attr->u.num;
 
+	attr=attr_search(attrs, NULL, attr_enable_expression);
+	if (attr)
+		item->enable_expression = g_strdup(attr->u.str);
+
 	attr = attr_search(attrs, NULL, attr_w);
 	if (attr) {
 		if (attr->u.num > ATTR_REL_MAXABS) {
@@ -208,11 +212,23 @@ osd_set_std_attr(struct attr **attrs, struct osd_item *item, int flags)
 void
 osd_std_config(struct osd_item *item, struct navit *navit)
 {
-	struct attr osd_configuration;
+	struct attr attr;
 	dbg(1,"enter\n");
-	if (!navit_get_attr(navit, attr_osd_configuration, &osd_configuration, NULL))
-		osd_configuration.u.num=-1;
-	item->configured = !!(osd_configuration.u.num & item->osd_configuration);
+	if (item->enable_expression) {
+		int error,configured;
+		attr.type=attr_navit;
+		attr.u.navit=navit;
+		configured=command_evaluate_to_int(&navit, item->enable_expression, &error);
+		if (error) {
+			dbg(0,"evaluating %s resulted in error %d\n", item->enable_expression, error);
+			configured=0;
+		}
+		item->configured = !!configured;
+	} else {
+		if (!navit_get_attr(navit, attr_osd_configuration, &attr, NULL))
+			attr.u.num=-1;
+		item->configured = !!(attr.u.num & item->osd_configuration);
+	}
 	graphics_overlay_disable(item->gr, !item->configured);
 }
 
diff --git a/navit/osd.h b/navit/osd.h
index 99b760dd4..21c27897e 100644
--- a/navit/osd.h
+++ b/navit/osd.h
@@ -44,6 +44,7 @@ struct osd_item {
 	struct callback *resize_cb;
 	int pressed;
 	char *command;
+	char *enable_expression;
 };
 
 /* prototypes */