Screen: adjustments, bug fixes and abstraction.

Line drawing code no longer assumes a particular screen as long as
it's interface includes OLEDDisplay.

Signed-off-by: Ramūnas Mažeikis <ramunasnezinomas@gmail.com>

2 files changed, 22 insertions, 9 deletions

diff --git a/src/device/screen.cpp b/src/device/screen.cpp
index cfabcc5..c923b99 100644
--- a/src/device/screen.cpp
+++ b/src/device/screen.cpp
@@ -1,7 +1,7 @@
 #include <time.h>
 #include <stdlib.h>
 #include <string.h>
-#include <SSD1306Brzo.h>
+#include <OLEDDisplay.h>
 #include <Wire.h>
 #include "screen.h"
 
@@ -9,6 +9,9 @@ void draw_lines(struct display_status *status);
 void update_lines(struct display_status *status);
 void init_msg(char *msg, size_t size);
 
+/* Effectively const. For type safety reasons. */
+static char NOTHING[] = {'\0'};
+
 void display_status_init(struct display_status *status, char *msg)
 {
 	status->delta = 2;	/* Currently default */
@@ -44,7 +47,7 @@ end:
 	return;
 }
 
-void display_update_scroll(struct display_status *status)
+int display_update_scroll(struct display_status *status)
 {
 	time_t crr_time = time(NULL);
 	/* Only scroll lines once a delta, because --- duh! */
@@ -54,9 +57,14 @@ void display_update_scroll(struct display_status *status)
 		update_lines(status);
 		draw_lines(status);
 	}
+	if (status->first_line == NOTHING && status->second_line == NOTHING) {
+		return END_OF_MESSAGE;
+	} else {
+		return 0;
+	}
 }
 
-void draw_lines(SSD1306Brzo *screen, struct display_status *status)
+void draw_lines(OLEDDisplay *screen, struct display_status *status)
 {
 	screen->clear();
 	screen->drawString(0, 0, status->first_line);
@@ -65,6 +73,10 @@ void draw_lines(SSD1306Brzo *screen, struct display_status *status)
 
 void update_lines(struct display_status *status)
 {
-	status->first_line = get_line(status, status->line_cursor);
-	status->second_line = get_line(status, status->line_cursor + 1);
+	status->first_line = (status->line_cursor * SCREEN_MAX_CHARS < status->message_len)
+			? status->message + status->line_cursor * SCREEN_MAX_CHARS
+			: NOTHING;
+	status->second_line = (status->line_cursor * SCREEN_MAX_CHARS < status->message_len)
+			? status->message + (status->line_cursor + 1) * SCREEN_MAX_CHARS
+			: NOTHING;
 }
\ No newline at end of file
diff --git a/src/device/screen.h b/src/device/screen.h
index 54734e5..5d0e3b3 100644
--- a/src/device/screen.h
+++ b/src/device/screen.h
@@ -7,7 +7,7 @@
 #define DEVICE_SCREEN_H
 
 #include <time.h>
-#include <SSD1306Brzo.h>
+#include <OLEDDisplay.h>
 #include <Wire.h>
 
 #define SCREEN_WIDTH		(128)
@@ -19,7 +19,7 @@
  * Struct that keeps track of the lines on the screen.
  */
 struct display_status {
-	SSD1306Brzo *screen;		/* Screen to draw on. */
+	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 */
@@ -32,8 +32,9 @@ struct display_status {
 /**
  * Displays scrolling text on the screen.
  */
-void display_update_scroll(struct display_status *status);
+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.
@@ -44,6 +45,6 @@ void display_update_scroll(struct display_status *status);
  *
  * msg		- message to scroll on the screen
  */
-void display_status_init(SSD1306Brzo *screen, struct display_status *status, char *msg);
+void display_status_init(OLEDDisplay *screen, struct display_status *status, char *msg);
 
 #endif /* DEVICE_SCREEN_H */
\ No newline at end of file