Fix in-key note spelling for MIDI input

[scherzo] / scherzo.c

diff --git a/scherzo.c b/scherzo.c
index dd7fdbf076109c5f3728280c6ab4b0c1f246e0aa..dacefa8e8e8e186ec9fa6f20b9f79f05ab34e420 100644 (file)
--- a/scherzo.c
+++ b/scherzo.c
@@ -280,8 +280,6 @@ on_key_press_event (GtkWidget *widget,
 
     if (pitch != PITCH_NOT_A_PITCH) 
     {
-       pitch = scherzo_key_spell_pitch (&scherzo->key, pitch);
-
        scherzo_press_note (scherzo, pitch);
 
        return TRUE;
@@ -389,8 +387,6 @@ on_key_release_event (unused (GtkWidget *widget),
 
     if (pitch != PITCH_NOT_A_PITCH)
     {
-       pitch = scherzo_key_spell_pitch (&scherzo->key, pitch);
-
        scherzo_release_note (scherzo, pitch);
 
        return TRUE;
@@ -926,7 +922,17 @@ scherzo_update_notes_and_chord (scherzo_t *scherzo)
        /* Don't print root pitch for octaves and inversions,
         * (since a pitch name alone looks like a major triad) */
        if (signature->num_degrees < 3) {
+           /* In fact, don't print anything for octaves and
+            * inversions for now. It leads to a bit of flashing when
+            * playing chords.
+            *
+            * FIXME: What I'd like to have here is a small timeout,
+            * such that names only appear once an interval has been
+            * held for at least 100 ms or so. With that, it would be
+            * nice to display the interval names once again.
+            *
            chord_name = talloc_strdup (local, signature->name);
+           */
        } else {
            _spell_chord_by_signature (&scherzo->notes_pressed,
                                       signature, *root);
@@ -961,11 +967,54 @@ scherzo_update_notes_and_chord (scherzo_t *scherzo)
     talloc_free (local);
 }
 
+static void
+scherzo_set_key (scherzo_t *scherzo, pitch_t pitch)
+{
+    scherzo_key_init (&scherzo->key, pitch);
+    score_set_key (scherzo->score, pitch);
+}
+
+static bool
+pitches_are_diatonic_scale (pitch_t *pitches, int num_pitches)
+{
+    int diatonic_half_steps[7] = {
+       0, 2, 4, 5, 7, 9, 11
+    };
+    int half_steps;
+    pitch_t root;
+    int i;
+
+    if (num_pitches < 7)
+       return 0;
+
+    root = pitches[0];
+
+    for (i = 0; i < 7; i++) {
+       half_steps = pitch_from_root_in_half_steps (pitches[i], root);
+       if (half_steps != diatonic_half_steps[i])
+           return false;
+    }
+
+    return true;
+}
+
 static void
 scherzo_press_note (scherzo_t *scherzo, pitch_t pitch)
 {
     int i;
 
+    pitch = scherzo_key_spell_pitch (&scherzo->key, pitch);
+
+#define NUM_RECENT_PITCHES 7
+    static pitch_t recent_pitches[NUM_RECENT_PITCHES];
+
+    memmove (recent_pitches, recent_pitches + 1,
+            (NUM_RECENT_PITCHES - 1) * sizeof (pitch_t));
+    recent_pitches[NUM_RECENT_PITCHES - 1] = pitch;
+
+    if (pitches_are_diatonic_scale (recent_pitches, NUM_RECENT_PITCHES))
+       scherzo_set_key (scherzo, recent_pitches[0]);
+
     /* Do nothing if this note is already pressed. */
     for (i = 0; i < scherzo->notes_pressed.num_pitches; i++)
        if (scherzo->notes_pressed.pitches[i] == pitch)
@@ -982,6 +1031,8 @@ scherzo_press_note (scherzo_t *scherzo, pitch_t pitch)
 static void
 scherzo_release_note (scherzo_t *scherzo, pitch_t pitch)
 {
+    pitch = scherzo_key_spell_pitch (&scherzo->key, pitch);
+
     pitch_group_remove_pitch_enharmonic (&scherzo->notes_pressed, pitch);
 
     scherzo_update_notes_and_chord (scherzo);
@@ -1236,8 +1287,7 @@ main (int argc, char *argv[])
     scherzo.pedal_pressed = 0;
 
     /* Default to key of C Major, naturally. */
-    scherzo_key_init (&scherzo.key, PITCH_CLASS_LITERAL (C, NATURAL));
-    score_set_key (scherzo.score, scherzo.key.pitch);
+    scherzo_set_key (&scherzo, PITCH_CLASS_LITERAL (C, NATURAL));
 
     mnemon_init (&scherzo.mnemon);
     /* XXX: Should create a default file if one cannot be loaded. */