X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=pitch.h;h=ffe9782c54b50cac05ba3470477f079afe31ddd6;hb=5b1797d26aff3a1b2f0cbe83583496b42abcd056;hp=4467aa86a825c239faa6842819c21d85b58fb1e6;hpb=54d2b1cb13bf52df22c93e58377a00b757644b94;p=scherzo

diff --git a/pitch.h b/pitch.h
index 4467aa8..ffe9782 100644
--- a/pitch.h
+++ b/pitch.h
@@ -60,6 +60,8 @@ typedef uint32_t pitch_t;
 #define PITCH_CLASS_LITERAL(literal_name, literal_accidental) \
     PITCH_LITERAL(literal_name, literal_accidental, 0)
 
+#define PITCH_NOT_A_PITCH ((pitch_t) -1)
+
 typedef enum pitch_accidental
 {
     PITCH_ACCIDENTAL_DOUBLE_FLAT,
@@ -108,4 +110,26 @@ pitch_raise_by_octaves (pitch_t pitch, int octaves);
 pitch_t
 pitch_lower_by_octaves (pitch_t pitch, int octaves);
 
+/* Number of half steps from 'root' up to 'pitch' (that is, counting
+ * the steps up a chromatic scale), within the same octave. */
+int
+pitch_from_root_in_half_steps (pitch_t pitch, pitch_t root);
+
+/* Respell 'pitch' to have a name that matches the (diatonic) scale
+ * 'degree' from 'root'.
+ *
+ * If the pitch is too distant from the specified degree to be
+ * respelled, the original pitch will be returned unmodified.
+ */
+pitch_t
+pitch_spell_as_degree (pitch_t pitch, pitch_t root, int degree);
+
+/* Return a MIDI note value corresponding to 'pitch' */
+unsigned char
+pitch_to_midi (pitch_t pitch);
+
+/* Return the pitch_t value corresponding to the given MIDI note value. */
+pitch_t
+pitch_from_midi (unsigned char midi_note);
+
 #endif /* PITCH_H */