Open MIDI device and display notes being played in real time.

Every time a key on the MIDI input device is pressed, a whole note appears
on the appropriate staff. When the key is released, the note disappears.

No ledger lines are drawn yet, and there appears to be a bug where notes
get stuck on (refusing to disappear after a key is released) triggered
most easily by pressing *many* keys simultaneously several times.

diff --git a/Makefile b/Makefile
index a00d6bf960e42b094ebf6aa882087007656b1ae2..db95a9d24fcc0e45b7d6cea7f91bbb32f5f601c0 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -8,9 +8,9 @@ scherzo_modules = $(scherzo_srcs:.c=.o)
 
 WARN_CFLAGS = -Wall -Wextra
 
-SCHERZO_CFLAGS = $(CFLAGS) $(WARN_CFLAGS) $(CONFIGURE_CFLAGS) $(extra_cflags) `pkg-config --cflags gtk+-2.0`
+SCHERZO_CFLAGS = $(CFLAGS) $(WARN_CFLAGS) $(CONFIGURE_CFLAGS) $(extra_cflags) `pkg-config --cflags gtk+-2.0 alsa`
 
-SCHERZO_LDFLAGS = $(LDFLAGS) `pkg-config --libs gtk+-2.0` -ltalloc
+SCHERZO_LDFLAGS = $(LDFLAGS) `pkg-config --libs gtk+-2.0 alsa` -ltalloc
 
 # The user has not set any verbosity, default to quiet mode and inform the
 # user how to enable verbose compiles.
@@ -40,7 +40,7 @@ DEPS := $(scherzo_srcs:%.c=.deps/%.d)
 scherzo: $(scherzo_modules)
        $(call quiet,CC $(CFLAGS)) $^ $(SCHERZO_LDFLAGS) -o $@
 
-CLEAN := $(CLEAN) scherzo $(chorale_modules)
+CLEAN := $(CLEAN) scherzo $(scherzo_modules)
 
 .PHONY : clean
 clean:

diff --git a/scherzo.c b/scherzo.c
index 329884da93764973e0d595265d85dd5e2ac9b061..e6a67ec1ce7bbc4e83046d9e94f2d10e7c5d1bcd 100644 (file)
--- a/scherzo.c
+++ b/scherzo.c
@@ -19,14 +19,23 @@
 #include <gtk/gtk.h>
 #include <gdk/gdkkeysyms.h>
 
+#include <asoundlib.h>
+
 #include "score.h"
 
 #define unused(foo) foo __attribute__((unused))
 
+#define MIDI_BUF_SIZE 4096
+
 typedef struct scherzo
 {
+    GtkWidget *window;
     score_t *score;
     int staff_height;
+    score_staff_t *treble;
+    score_staff_t *bass;
+    int midi_fd;
+    snd_midi_event_t *snd_midi_event;
 } scherzo_t;
 
 static int
@@ -105,14 +114,148 @@ on_key_press_event (GtkWidget *widget,
     return FALSE;
 }
 
+static void
+_midi_to_score_pitch_and_octave (unsigned char midi_note,
+                                score_pitch_t *pitch,
+                                int *octave)
+{
+    *octave = midi_note / 12 - 1;
+
+    switch (midi_note % 12)
+    {
+    case 0:
+       *pitch = SCORE_PITCH_C;
+       break;
+    case 1:
+       *pitch = SCORE_PITCH_Cs;
+       break;
+    case 2:
+       *pitch = SCORE_PITCH_D;
+       break;
+    case 3:
+       *pitch = SCORE_PITCH_Ds;
+       break;
+    case 4:
+       *pitch = SCORE_PITCH_E;
+       break;
+    case 5:
+       *pitch = SCORE_PITCH_F;
+       break;
+    case 6:
+       *pitch = SCORE_PITCH_Fs;
+       break;
+    case 7:
+       *pitch = SCORE_PITCH_G;
+       break;
+    case 8:
+       *pitch = SCORE_PITCH_Gs;
+       break;
+    case 9:
+       *pitch = SCORE_PITCH_A;
+       break;
+    case 10:
+       *pitch = SCORE_PITCH_As;
+       break;
+    case 11:
+       *pitch = SCORE_PITCH_B;
+       break;
+    }
+}
+
+static void
+scherzo_add_note_midi (scherzo_t *scherzo, unsigned char midi_note)
+{
+    score_staff_t *staff;
+    score_pitch_t pitch;
+    int octave;
+
+    /* Anything at Middle C and above goes on the treble staff by default. */
+    if (midi_note >= 60)
+       staff = scherzo->treble;
+    else
+       staff = scherzo->bass;
+
+    _midi_to_score_pitch_and_octave (midi_note, &pitch, &octave);
+
+    score_staff_add_note (staff, pitch, octave, SCORE_DURATION_WHOLE);
+}
+
+static void
+scherzo_remove_note_midi (scherzo_t *scherzo, unsigned char midi_note)
+{
+    score_staff_t *staff;
+    score_pitch_t pitch;
+    int octave;
+    score_note_t *note;
+
+    /* Anything at Middle C and above goes on the treble staff by default. */
+    if (midi_note >= 60)
+       staff = scherzo->treble;
+    else
+       staff = scherzo->bass;
+
+    _midi_to_score_pitch_and_octave (midi_note, &pitch, &octave);
+
+    note = score_staff_find_note (staff, pitch, octave, SCORE_DURATION_WHOLE);
+    score_staff_remove_note (staff, note);
+}
+
+static int
+on_midi_input (unused (GIOChannel *channel),
+              unused (GIOCondition condition),
+              void *user_data)
+{
+    unsigned char buf[MIDI_BUF_SIZE], *next;
+    scherzo_t *scherzo = user_data;
+    ssize_t remaining;
+    snd_seq_event_t event;
+
+    remaining = read (scherzo->midi_fd, buf, MIDI_BUF_SIZE);
+
+    next = buf;
+    while (remaining) {
+       long consumed;
+
+       consumed = snd_midi_event_encode (scherzo->snd_midi_event,
+                                         next, remaining, &event);
+
+       remaining -= consumed;
+
+       switch (event.type) {
+       case SND_SEQ_EVENT_NONE:
+           /* Incomplete event. Nothing to do. */
+           break;
+       case SND_SEQ_EVENT_NOTEON:
+           scherzo_add_note_midi (scherzo, event.data.note.note);
+           gtk_widget_queue_draw (scherzo->window);
+           break;
+       case SND_SEQ_EVENT_NOTEOFF:
+           scherzo_remove_note_midi (scherzo, event.data.note.note);
+           gtk_widget_queue_draw (scherzo->window);
+           break;
+       case SND_SEQ_EVENT_CLOCK:
+           /* Ignore for now as my piano sends a constant stream of these. */
+           break;
+       case SND_SEQ_EVENT_SENSING:
+           /* Ignore for now as my piano sends a constant stream of these. */
+           break;
+       default:
+           fprintf (stderr, "Fixme: Do not yet know how to handle MIDI event %d\n",
+                    event.type);
+           break;
+       }
+    }
+    
+    /* Return TRUE to continue to get called in the future. */
+    return TRUE;
+}
+
 int
 main (int argc, char *argv[])
 {
-    GtkWidget *window;
     GtkWidget *drawing_area;
     scherzo_t scherzo;
-    score_staff_t *treble;
-    score_staff_t *bass;
+    int err;
 
     gtk_init (&argc, &argv);
 
@@ -121,49 +264,52 @@ main (int argc, char *argv[])
     score_set_staff_height (scherzo.score, scherzo.staff_height);
 
     score_add_brace (scherzo.score, 2);
-    treble = score_add_staff (scherzo.score, SCORE_CLEF_G);
-    bass = score_add_staff (scherzo.score, SCORE_CLEF_F);
-
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (D, 4, WHOLE));
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (E, 4, WHOLE));
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (F, 4, WHOLE));
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (G, 4, WHOLE));
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (A, 4, WHOLE));
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (B, 4, WHOLE));
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (C, 5, WHOLE));
-    score_staff_add_note (treble, SCORE_BUILD_NOTE (D, 5, WHOLE));
-
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (B, 2, WHOLE));
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (C, 3, WHOLE));
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (D, 3, WHOLE));
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (E, 3, WHOLE));
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (F, 3, WHOLE));
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (G, 3, WHOLE));
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (A, 3, WHOLE));
-    score_staff_add_note (bass, SCORE_BUILD_NOTE (B, 3, WHOLE));
-
-    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
-
-    gtk_window_set_default_size (GTK_WINDOW (window), 600, 400);
-
-    g_signal_connect (window, "delete-event",
+    scherzo.treble = score_add_staff (scherzo.score, SCORE_CLEF_G);
+    scherzo.bass = score_add_staff (scherzo.score, SCORE_CLEF_F);
+
+    err = snd_midi_event_new (MIDI_BUF_SIZE, &scherzo.snd_midi_event);
+    if (err) {
+       fprintf (stderr, "Out of memory.\n");
+       return 1;
+    }
+
+#define MIDI_DEVICE "/dev/midi1"
+    scherzo.midi_fd = open (MIDI_DEVICE, O_RDONLY);
+    if (scherzo.midi_fd < 0) {
+       printf ("failed to open " MIDI_DEVICE ". Midi input will not be available.\n");
+    } else {
+       GIOChannel *channel;
+
+       channel = g_io_channel_unix_new (scherzo.midi_fd);
+       g_io_channel_set_encoding (channel, NULL, NULL);
+       g_io_add_watch (channel, G_IO_IN, on_midi_input, &scherzo);
+    }
+
+    scherzo.window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+
+    gtk_window_set_default_size (GTK_WINDOW (scherzo.window), 600, 400);
+
+    g_signal_connect (scherzo.window, "delete-event",
                      G_CALLBACK (on_delete_event_quit), NULL);
 
     drawing_area = gtk_drawing_area_new ();
 
-    gtk_container_add (GTK_CONTAINER (window), drawing_area);
+    gtk_container_add (GTK_CONTAINER (scherzo.window), drawing_area);
 
     g_signal_connect (drawing_area, "expose-event",  
                      G_CALLBACK (on_expose_event_draw),
                      &scherzo);
 
-    g_signal_connect (window, "key-press-event",  
+    g_signal_connect (scherzo.window, "key-press-event",  
                      G_CALLBACK (on_key_press_event),
                      &scherzo);
     
-    gtk_widget_show_all (window);
+    gtk_widget_show_all (scherzo.window);
     
     gtk_main ();
 
+    snd_midi_event_free (scherzo.snd_midi_event);
+    talloc_free (scherzo.score);
+
     return 0;
 }

diff --git a/score.c b/score.c
index 7a1c231a4b82cfdcef0d972dcf88ac6c1168e645..b2866096e3c0183c254ae6ae3838e9325c637dcb 100644 (file)
--- a/score.c
+++ b/score.c
@@ -18,6 +18,8 @@
  * along with this program.  If not, see http://www.gnu.org/licenses/ .
  */
 
+#include <string.h>
+
 #include "score.h"
 
 struct score_staff
@@ -222,7 +224,6 @@ _draw_staff (score_t *score, cairo_t *cr,
 {
     int i;
     cairo_glyph_t clef_glyph;
-    cairo_text_extents_t clef_extents;
 
     cairo_save (cr);
 
@@ -249,8 +250,6 @@ _draw_staff (score_t *score, cairo_t *cr,
     cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); /* black */
     cairo_show_glyphs (cr, &clef_glyph, 1);
 
-    cairo_glyph_extents (cr, &clef_glyph, 1, &clef_extents);
-
     /* Draw staff lines */
     for (i = 0; i < 5; i++) {
        cairo_move_to (cr, 0, i * score->space_height + score->line_width / 2.0);
@@ -263,12 +262,14 @@ _draw_staff (score_t *score, cairo_t *cr,
     cairo_stroke (cr);
 
     /* Make space for clef before drawing notes */
-    cairo_translate (cr, (int) (1.5 * clef_extents.width), 0);
+    cairo_translate (cr, (int) (4 * score->space_height), 0);
 
     /* Draw notes */
     for (i = 0; i < staff->num_notes; i++) {
        _draw_note (score, cr, staff, staff->notes[i]);
+       /* Draw all notes concurrent for now (as a chord)
        cairo_translate (cr, score->space_height * 2.0, 0);
+       */
     }
 
     cairo_restore (cr);
@@ -402,3 +403,47 @@ score_staff_add_note (score_staff_t *staff,
     return note;
 }
 
+void
+score_staff_remove_note (score_staff_t *staff, score_note_t *note)
+{
+    int i;
+
+    for (i = 0; i < staff->num_notes; i++)
+       if (staff->notes[i] == note)
+           break;
+
+    if (i == staff->num_notes)
+       return;
+
+    if (i < staff->num_notes - 1)
+    {
+       memmove (staff->notes + i,
+                staff->notes + i + 1, 
+                (staff->num_notes - 1 - i) * sizeof (score_note_t *));
+    }
+
+    staff->num_notes -= 1;
+}
+
+score_note_t *
+score_staff_find_note (score_staff_t *staff,
+                      score_pitch_t pitch,
+                      int octave,
+                      score_duration_t duration)
+{
+    int i;
+    score_note_t *note;
+
+    for (i = 0; i < staff->num_notes; i++) {
+       note = staff->notes[i];
+       if (note->pitch == pitch &&
+           note->octave == octave &&
+           note->duration == duration)
+       {
+           return note;
+       }
+    }
+
+    return NULL;
+}
+

diff --git a/score.h b/score.h
index 98dd26f89cb9f20f216e84afcd43de872a7e8d5b..a07b9266d4aa5725f0221200c791165e407d81dd 100644 (file)
--- a/score.h
+++ b/score.h
@@ -178,6 +178,18 @@ score_staff_add_note (score_staff_t *staff,
                      int octave,
                      score_duration_t);
 
+/* Remove the given note from the given staff. */
+void
+score_staff_remove_note (score_staff_t *staff, score_note_t *note);
+
+/* Return the first note on the given staff with the given pitch,
+ * octave, and durations. Returns NULL if no match is found. */
+score_note_t *
+score_staff_find_note (score_staff_t *staff,
+                      score_pitch_t pitch,
+                      int octave,
+                      score_duration_t duration);
+
 /* Draw the given score_t onto the given cairo_t.
  *
  * The caller can call cairo_translate before calling score_draw to