[Keyboard] Add stront keyboard (#21035)

keyboards/stront/lvgl_helpers.h

@@ -0,0 +1,13 @@
+// Copyright 2023 zzeneg (@zzeneg)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "qp_lvgl.h"
+
+lv_obj_t *create_button(lv_obj_t *parent, const char *text, lv_style_t *style, lv_style_t *style_pressed);
+
+void use_flex_row(void *obj);
+void use_flex_column(void *obj);
+void toggle_state(void *obj, lv_state_t state, bool enabled);
+void toggle_hidden(void *obj, bool visible);
+void resize_font(void *label, int32_t v);
+void debug_set_obj_border(lv_obj_t *obj);