Break out font stuff into new module

utils/font.c

@@ -0,0 +1,57 @@
+/** @file   font.h
+    @author M. P. Hayes, UCECE
+    @date   18 Sep 2011
+    @brief  Font lookup.
+*/
+
+#include "font.h"
+
+
+/** Determine if character in font.
+    @param font pointer to font structure
+    @param ch character to check
+    @return non-zero if character is in font.  */
+bool font_contains_p (font_t *font, char ch)
+{
+    int8_t index;
+
+    if (!font)
+        return 0;
+
+    index = ch - font->offset;
+    return index >= 0 && index < font->size;
+}
+
+
+/** Determine if pixel on or off.
+    @param font pointer to font structure
+    @param ch character to display
+    @param col column of font element
+    @param row row of font element
+    @return 1 if pixel on; if pixel out of bounds return 0.  */
+bool font_pixel_get (font_t *font, char ch, uint8_t col, uint8_t row)
+{
+    int8_t index;
+    font_data_t *char_data;
+    uint8_t offset;
+
+    if (!font)
+        return 0;
+
+    /* Check if desired pixel within size of an element.  */
+    if (col >= font->width || row >= font->height)
+        return 0;
+
+    /* Find index of font element.  */
+    index = ch - font->offset;
+    if (index < 0 || index >= font->size)
+        return 0;
+
+    /* Get start of font element data for ch.  */
+    char_data = &font->data[index * font->bytes];
+
+    /* Extract whether pixel should be on or off.  */
+    offset = row * font->width + col;
+    return (char_data[offset >> 3] & BIT (offset % 8)) != 0;
+}
+

utils/font.h

@@ -1,7 +1,7 @@
 /** @file   font.h
     @author M. P. Hayes, UCECE
     @date   1 March 2007
-    @brief  Font definition.
+    @brief  Font lookup.
 */
 
 #ifndef FONT_H
@@ -31,11 +31,20 @@ typedef const struct
 } font_t;
 
 
-/** Return the first character in the font.  */
-#define FONT_FIRST(font) ((font)->offset)
+/** Determine if character in font.
+    @param font pointer to font structure
+    @param ch character to check
+    @return non-zero if character is in font.  */
+bool font_contains_p (font_t *font, char ch);
 
-/** Return the last character in the font.  */
-#define FONT_LAST(font) ((font)->offset + (font)->size - 1)
 
+/** Determine if pixel on or off.
+    @param font pointer to font structure
+    @param ch character to display
+    @param col column of font element
+    @param row row of font element
+    @return 1 if pixel on; if pixel out of bounds return 0.  */
+bool
+font_pixel_get (font_t *font, char ch, uint8_t col, uint8_t row);
 
 #endif

utils/tinygl.c

@@ -123,24 +123,7 @@ void tinygl_clear (void)
     @return 1 if pixel on; if pixel out of bounds return 0.  */
 static bool tinygl_font_pixel_get (char ch, uint8_t col, uint8_t row)
 {
-    int8_t index;
-    font_data_t *char_data;
-    uint8_t offset;
-
-    if (!font || col >= font->width || row >= font->height)
-        return 0;
-
-    /* Find index of font entry.  */
-    index = ch - font->offset;
-    if (index < 0 || index >= font->size)
-        return 0;    
-
-    /* Get start of font entry data for ch.  */
-    char_data = &font->data[index * font->bytes];
-
-    /* Extract whether pixel should be on or off.  */
-    offset = row * font->width + col;
-    return (char_data[offset / 8] & BIT (offset % 8)) != 0;
+    return font_pixel_get (font, ch, col, row);
 }