migrating to esp-idf V4.0 gcc 8.2 and CMake

components/platform_display/display.h

@@ -0,0 +1,48 @@
+/* 
+ *  (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
+
+#include "gds.h"
+
+/* 
+ The displayer is not thread-safe and the caller must ensure use its own 
+ mutexes if it wants something better. Especially, text() line() and draw()
+ are not protected against each other.
+ In text mode (text/line) when using DISPLAY_SUSPEND, the displayer will 
+ refreshed line 2 one last time before suspending itself. As a result if it
+ is in a long sleep (scrolling pause), the refresh will happen after wakeup. 
+ So it can conflict with other display direct writes that have been made during
+ sleep. Note that if DISPLAY_SHUTDOWN has been called meanwhile, it (almost) 
+ never happens
+ The display_bus() shall be subscribed by other displayers so that at least
+ when this one (the main) wants to take control over display, it can signal
+ that to others
+*/ 
+extern struct GDS_Device *display;
+  
+enum displayer_cmd_e 	{ DISPLAYER_SHUTDOWN, DISPLAYER_ACTIVATE, DISPLAYER_SUSPEND, DISPLAYER_TIMER_PAUSE, DISPLAYER_TIMER_RUN };
+enum displayer_time_e 	{ DISPLAYER_ELAPSED, DISPLAYER_REMAINING };
+
+enum display_bus_cmd_e { DISPLAY_BUS_TAKE, DISPLAY_BUS_GIVE };
+bool (*display_bus)(void *from, enum display_bus_cmd_e cmd);
+
+void displayer_scroll(char *string, int speed);
+void displayer_control(enum displayer_cmd_e cmd, ...);
+void displayer_metadata(char *artist, char *album, char *title);
+void displayer_timer(enum displayer_time_e mode, int elapsed, int duration);