1 files changed, 50 insertions, 0 deletions
diff --git a/src/device/screen.h b/src/device/screen.h
new file mode 100644
index 0000000..5d0e3b3
--- /dev/null
+++ b/src/device/screen.h
@@ -0,0 +1,50 @@
+/**
+ * Simple API for scrolling lines. Keeps things simple by not even assuming
+ * which screen is being drawn on.
+ */
+
+#ifndef DEVICE_SCREEN_H
+#define DEVICE_SCREEN_H
+
+#include <time.h>
+#include <OLEDDisplay.h>
+#include <Wire.h>
+
+#define SCREEN_WIDTH		(128)
+#define SCREEN_HEIGHT		(32)
+#define FONT_WIDTH		(8)
+#define SCREEN_MAX_CHARS	(SCREEN_WIDTH / FONT_WIDTH)
+
+/**
+ * Struct that keeps track of the lines on the screen.
+ */
+struct display_status {
+	OLEDDisplay *screen;		/* Screen to draw on. */
+	time_t delta;			/* Seconds/Line */
+	time_t last_scroll_time;	/* Last second the line was scrolled */
+	char *message;			/* Entire message to be shown */
+	char *first_line;		/* First line on display */
+	char *second_line;		/* Second line on display */
+	size_t message_len;		/* Length of the message */
+	size_t line_cursor;		/* Index of the first line being displayed. */
+};
+
+/**
+ * Displays scrolling text on the screen.
+ */
+int display_update_scroll(struct display_status *status);
+
+#define END_OF_MESSAGE	(1 << 0)
+/**
+ * Initialises display_status structure so it can be used for
+ * display_update_scroll.
+ *
+ * screen	- screen to draw on
+ *
+ * status	- structure to Initialise
+ *
+ * msg		- message to scroll on the screen
+ */
+void display_status_init(OLEDDisplay *screen, struct display_status *status, char *msg);
+
+#endif /* DEVICE_SCREEN_H */
+\ No newline at end of file