refactor display

- part of components
- separation between LMS & driver
- move slimp message to squeezelite

components/services/display.h

@@ -0,0 +1,33 @@
+/* 
+ *  (c) Philippe G. 2019, philippe_44@outlook.com
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#pragma once
+
+#define DISPLAY_CLEAR 	0x01
+#define DISPLAY_UPDATE	0x02
+
+enum display_pos_e { DISPLAY_TOP_LEFT, DISPLAY_MIDDLE_LEFT, DISPLAY_BOTTOM_LEFT, DISPLAY_CENTER };
+
+extern struct display_s {
+	bool (*init)(char *config, char *welcome);
+	void (*on)(bool state);
+	void (*brightness)(u8_t level);
+	void (*text)(enum display_pos_e pos, int attribute, char *msg);
+	void (*update)(void);
+	void (*v_draw)(u8_t *data);
+} *display;