# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1542063735 -3600
# Node ID b8630308b29e80d479bf12e04fc141743322e54c
# Parent  e7cf90210d941b89c889c9350b8f4289fb34ed90
Introduced an undefined character definition. Added string writing support.

diff -r e7cf90210d94 -r b8630308b29e include/font.h
--- a/include/font.h	Mon Nov 12 17:55:53 2018 +0100
+++ b/include/font.h	Tue Nov 13 00:02:15 2018 +0100
@@ -57,4 +57,7 @@
 int write_char(display_config_t *cfg, font_config_t *fcfg, char c,
                int x, int y, uint8_t colour);
 
+void write_string(display_config_t *cfg, font_config_t *fcfg, const char *s,
+                  int *x, int *y, uint8_t colour);
+
 #endif /* __FONT_H__ */
diff -r e7cf90210d94 -r b8630308b29e lib/font.c
--- a/lib/font.c	Mon Nov 12 17:55:53 2018 +0100
+++ b/lib/font.c	Tue Nov 13 00:02:15 2018 +0100
@@ -24,6 +24,14 @@
 
 
 
+/* Space is a special case. */
+
+static char_definition_t space = {
+    .width = 3, .height = 9, .data = {0, 0, 0, 0, 0, 0, 0, 0, 0}
+    };
+
+
+
 /* Initialise a font configuration. */
 
 void init_font(font_config_t *cfg, uint8_t *chars, uint32_t *table,
@@ -47,7 +55,7 @@
     if ((c >= fcfg->base) && (c < fcfg->limit))
         return (char_definition_t *) ((uint8_t *) fcfg->chars + fcfg->table[c - fcfg->base]);
     else
-        return NULL;
+        return &space;
 }
 
 /* Write a character to the screen, returning the next character position. */
@@ -61,11 +69,6 @@
             *displayline = cfg->screen_start + y * cfg->line_length,
             bitmap, mask;
 
-    /* Space is a special case. */
-
-    if (c == ' ')
-        return x + 3;
-
     for (sy = 0, dy = y; (sy < chardef->height) && (dy < cfg->line_count); sy++, dy++)
     {
         if (displayline >= cfg->screen_limit)
@@ -85,3 +88,26 @@
 
     return x + chardef->width;
 }
+
+/* Write a string to the screen, updating the coordinates to indicate the next
+   character position. */
+
+void write_string(display_config_t *cfg, font_config_t *fcfg, const char *s,
+                  int *x, int *y, uint8_t colour)
+{
+    const int line_height = 9;
+
+    while (*s)
+    {
+        if (*x + get_char_definition(fcfg, *s)->width > cfg->line_length)
+        {
+            *x = 0; *y += line_height;
+        }
+
+        if (*y + line_height >= cfg->line_count)
+            break;
+
+        *x = write_char(cfg, fcfg, *s, *x, *y, colour);
+        s++;
+    }
+}