u8 msg_length; /* length of current_message */
u8 wrap_mode; /* whether to scroll or alternate between msgs */
u8 scroll_point; /* how far through the message we have scrolled */
+bool have_scrolled; /* true after one scroll (used for scroll_msg())*/
/* private prototypes */
void display_send_byte(char c);
void display_reset();
void display_update();
-void set_msg(char* newmsg, u8 wrap) {
- char* dest = current_message;
+void append_msg(char* newmsg, u8 wrap) {
+ char* dest = current_message+msg_length;
/* equivalent of a string copy */
- /* while (dest++ = newmsg++); */
- msg_length = 0;
while (newmsg) {
dest = newmsg;
dest++;
msg_length++;
}
wrap_mode = wrap;
+}
+
+void set_msg(char* newmsg, u8 wrap) {
+ msg_length = 0;
+ append_msg(newmsg, wrap);
scroll_point = 0;
display_update();
}
+void scroll_msg(char* newmsg) {
+ /* puts a message on display and does not return until the message has
+ * scrolled across once.
+ */
+ set_msg(newmsg, WRAP_SCROLL);
+ have_scrolled = 0;
+ while (!have_scrolled);
+}
+
void display_shift() {
/* update the display for WRAP_SCROLL or WRAP_ALTERNATE modes */
switch (wrap_mode) {
case WRAP_SCROLL:
+ case WRAP_ALTERNATE:
scroll_point++;
- if (scroll_point >= msg_length) scroll_point = 0;
+ if (scroll_point >= msg_length) {
+ scroll_point = 0;
+ have_scrolled = 1;
+ }
display_update();
break;
- case WRAP_ALTERNATE:
- scroll_point += 10;
- if (scroll_point >= msg_length) scroll_point = 0;
- /* the above means that only sets of multiples of 10 characters
- * are shown (excess ones are not) */
- display_update();
}
}
u8 i;
for (i=0; i < 10; i++) {
- display_buffer[i] = current_message[(i+scroll_point)%msg_length];
+ display_buffer[i] = current_message[
+ (i+(wrap_mode==WRAP_ALTERNATE?scroll_point/10:scroll_point))
+ %msg_length];
}
/* hmmm, will this cause some flickering of the display? */