expo: Support simple themes

It is a pain to manually set the fonts of all objects to be consistent.
Some spacing settings are also better set globally than by manually
positioning each object.

Add a 'theme' to the expo, to hold this information. For now it includes
only the font size.

Signed-off-by: Simon Glass <sjg@chromium.org>

boot/expo.c

@@ -231,3 +231,23 @@ int expo_action_get(struct expo *exp, struct expo_action *act)
 
 	return act->type == EXPOACT_NONE ? -EAGAIN : 0;
 }
+
+int expo_apply_theme(struct expo *exp, ofnode node)
+{
+	struct scene *scn;
+	struct expo_theme *theme = &exp->theme;
+	int ret;
+
+	log_debug("Applying theme %s\n", ofnode_get_name(node));
+
+	memset(theme, '\0', sizeof(struct expo_theme));
+	ofnode_read_u32(node, "font-size", &theme->font_size);
+
+	list_for_each_entry(scn, &exp->scene_head, sibling) {
+		ret = scene_apply_theme(scn, theme);
+		if (ret)
+			return log_msg_ret("app", ret);
+	}
+
+	return 0;
+}

boot/scene.c

@@ -466,3 +466,31 @@ int scene_calc_dims(struct scene *scn, bool do_menus)
 
 	return 0;
 }
+
+int scene_apply_theme(struct scene *scn, struct expo_theme *theme)
+{
+	struct scene_obj *obj;
+	int ret;
+
+	/* Avoid error-checking optional items */
+	scene_txt_set_font(scn, scn->title_id, NULL, theme->font_size);
+
+	list_for_each_entry(obj, &scn->obj_head, sibling) {
+		switch (obj->type) {
+		case SCENEOBJT_NONE:
+		case SCENEOBJT_IMAGE:
+		case SCENEOBJT_MENU:
+			break;
+		case SCENEOBJT_TEXT:
+			scene_txt_set_font(scn, obj->id, NULL,
+					   theme->font_size);
+			break;
+		}
+	}
+
+	ret = scene_arrange(scn);
+	if (ret)
+		return log_msg_ret("arr", ret);
+
+	return 0;
+}

boot/scene_internal.h

@@ -89,6 +89,15 @@ int scene_calc_dims(struct scene *scn, bool do_menus);
  */
 int scene_menu_arrange(struct scene *scn, struct scene_obj_menu *menu);
 
+/**
+ * scene_apply_theme() - Apply a theme to a scene
+ *
+ * @scn: Scene to update
+ * @theme: Theme to apply
+ * Returns: 0 if OK, -ve on error
+ */
+int scene_apply_theme(struct scene *scn, struct expo_theme *theme);
+
 /**
  * scene_menu_send_key() - Send a key to a menu for processing
  *

doc/develop/expo.rst

@@ -155,8 +155,13 @@ such as scanning devices for more bootflows.
 Themes
 ------
 
-Expo does not itself support themes. The bootflow_menu implement supposed a
-basic theme, applying font sizes to the various text objects in the expo.
+Expo supports simple themes, for setting the font size, for example. Use the
+expo_apply_theme() function to load a theme, passing a node with the required
+properties:
+
+font-size
+    Font size to use for all text (type: u32)
+
 
 API documentation
 -----------------

include/expo.h

@@ -7,6 +7,7 @@
 #ifndef __SCENE_H
 #define __SCENE_H
 
+#include <dm/ofnode_decl.h>
 #include <linux/list.h>
 
 struct udevice;
@@ -42,6 +43,19 @@ struct expo_action {
 	};
 };
 
+/**
+ * struct expo_theme - theme for the expo
+ *
+ * @font_size: Default font size for all text
+ * @menu_inset: Inset width (on each side and top/bottom) for menu items
+ * @menuitem_gap_y: Gap between menu items in pixels
+ */
+struct expo_theme {
+	u32 font_size;
+	u32 menu_inset;
+	u32 menuitem_gap_y;
+};
+
 /**
  * struct expo - information about an expo
  *
@@ -57,6 +71,7 @@ struct expo_action {
  * type set to EXPOACT_NONE if there is no action
  * @text_mode: true to use text mode for the menu (no vidconsole)
  * @priv: Private data for the controller
+ * @theme: Information about fonts styles, etc.
  * @scene_head: List of scenes
  * @str_head: list of strings
  */
@@ -69,6 +84,7 @@ struct expo {
 	struct expo_action action;
 	bool text_mode;
 	void *priv;
+	struct expo_theme theme;
 	struct list_head scene_head;
 	struct list_head str_head;
 };
@@ -583,4 +599,12 @@ int expo_send_key(struct expo *exp, int key);
  */
 int expo_action_get(struct expo *exp, struct expo_action *act);
 
+/**
+ * expo_apply_theme() - Apply a theme to an expo
+ *
+ * @exp: Expo to update
+ * @node: Node containing the theme
+ */
+int expo_apply_theme(struct expo *exp, ofnode node);
+
 #endif /*__SCENE_H */

test/boot/expo.c

@@ -226,7 +226,7 @@ static int expo_object(struct unit_test_state *uts)
 }
 BOOTSTD_TEST(expo_object, UT_TESTF_DM | UT_TESTF_SCAN_FDT);
 
-/* Check setting object attributes */
+/* Check setting object attributes and using themes */
 static int expo_object_attr(struct unit_test_state *uts)
 {
 	struct scene_obj_menu *menu;
@@ -236,6 +236,7 @@ static int expo_object_attr(struct unit_test_state *uts)
 	struct expo *exp;
 	ulong start_mem;
 	char name[100];
+	ofnode node;
 	char *data;
 	int id;
 
@@ -273,6 +274,11 @@ static int expo_object_attr(struct unit_test_state *uts)
 	ut_asserteq(-ENOENT, scene_menu_set_title(scn, OBJ_TEXT2, OBJ_TEXT));
 	ut_asserteq(-EINVAL, scene_menu_set_title(scn, OBJ_MENU, OBJ_TEXT2));
 
+	node = ofnode_path("/bootstd/theme");
+	ut_assert(ofnode_valid(node));
+	ut_assertok(expo_apply_theme(exp, node));
+	ut_asserteq(30, txt->font_size);
+
 	expo_destroy(exp);
 
 	ut_assertok(ut_check_delta(start_mem));