Add preliminary chord analysis

[scherzo] / score.c

diff --git a/score.c b/score.c
index db07d5e9d57f33436688db8741d2a4442d519760..e319af0c238abaf594afee0088bc8c580de6f59e 100644 (file)
--- a/score.c
+++ b/score.c
@@ -26,6 +26,9 @@ struct score_staff
 {
     score_clef_t clef;
 
+    score_chord_t **chords;
+    int num_chords;
+
     score_note_t **notes;
     int num_notes;
 
@@ -178,6 +181,38 @@ _score_note_to_line (score_staff_t *staff, score_note_t *note)
     return c_line - (name - SCORE_PITCH_NAME_C) / 2.0 - 3.5 * (note->octave - 4);
 }
 
+/* chord->width is updated as a side effect */
+static void
+_draw_chord (score_t *score, cairo_t *cr,
+            score_staff_t *staff, score_chord_t *chord)
+{
+    cairo_text_extents_t chord_extents;
+    double total_staff_height;
+
+    /* XXX: The staff should manage this height itself. */
+    total_staff_height = (staff->upper_ledger_lines * score->space_height +
+                         score->staff_height +
+                         staff->lower_ledger_lines * score->space_height);
+
+    cairo_save (cr);
+
+    cairo_text_extents (cr, chord->name, &chord_extents);
+
+    cairo_select_font_face (cr, "serif", 0, 0);
+    cairo_set_font_size (cr, score->space_height * 3);
+
+    if (staff->clef == SCORE_CLEF_G)
+       cairo_move_to (cr, 0, - score->space_height * 0.5);
+    else
+       cairo_move_to (cr, 0, score->space_height * 0.5 + total_staff_height + chord_extents.y_bearing);
+
+    cairo_show_text (cr, chord->name);
+
+    chord->width = chord_extents.x_advance;
+
+    cairo_restore (cr);
+}
+
 static void
 _draw_note (score_t *score, cairo_t *cr,
            score_staff_t *staff, score_note_t *note)
@@ -300,6 +335,16 @@ _draw_staff (score_t *score, cairo_t *cr,
     /* Make space for clef before drawing notes */
     cairo_translate (cr, (int) (4 * score->space_height), 0);
 
+    /* Draw chord symbols */
+    cairo_save (cr);
+    {
+       for (i = 0; i < staff->num_chords; i++) {
+           _draw_chord (score, cr, staff, staff->chords[i]);
+           cairo_translate (cr, staff->chords[i]->width, 0.0);
+       }
+    }
+    cairo_restore (cr);
+
     /* Draw notes */
     for (i = 0; i < staff->num_notes; i++) {
        _draw_note (score, cr, staff, staff->notes[i]);
@@ -409,6 +454,9 @@ score_add_staff (score_t *score, score_clef_t clef)
     staff->notes = NULL;
     staff->num_notes = 0;
 
+    staff->chords = NULL;
+    staff->num_chords = 0;
+
     staff->upper_ledger_lines = 0;
     staff->lower_ledger_lines = 0;
 
@@ -427,6 +475,61 @@ score_add_staff (score_t *score, score_clef_t clef)
     return staff;
 }
 
+score_chord_t *
+score_add_chord (score_staff_t *staff,
+                const char *name)
+{
+    score_chord_t *chord;
+
+    chord = talloc (staff, score_chord_t);
+    if (chord == NULL)
+       return NULL;
+
+    chord->staff = staff;
+    chord->name = talloc_strdup (chord, name);
+
+    /* The width will get set correctly the first time _draw_chord is
+     * called. */
+    chord->width = 0.0;
+
+    staff->num_chords++;
+    staff->chords = talloc_realloc (staff,
+                                   staff->chords,
+                                   score_chord_t*,
+                                   staff->num_chords);
+    if (staff->chords == NULL) {
+       staff->num_chords = 0;
+       return NULL;
+    }
+
+    staff->chords[staff->num_chords - 1] = chord;
+
+    return chord;
+}
+
+void
+score_remove_chord (score_chord_t *chord)
+{
+    score_staff_t *staff = chord->staff;
+    int i;
+
+    for (i = 0; i < staff->num_chords; i++)
+       if (staff->chords[i] == chord)
+           break;
+
+    if (i == staff->num_chords)
+       return;
+
+    if (i < staff->num_chords - 1)
+    {
+       memmove (staff->chords + i,
+                staff->chords + i + 1, 
+                (staff->num_chords - 1 - i) * sizeof (score_chord_t *));
+    }
+
+    staff->num_chords -= 1;
+}
+
 score_note_t *
 score_add_note (score_staff_t *staff,
                score_pitch_t pitch,