gtk_pianokeyboard.c

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/*-
 * Copyright (c) 2007, 2008 Edward Tomasz Napiera�ła <trasz@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * This is piano_keyboard, piano keyboard-like GTK+ widget.  It contains
 * no MIDI-specific code.
 *
 * For questions and comments, contact Edward Tomasz Napierala <trasz@FreeBSD.org>.
 */

#include <assert.h>
#include <string.h>
#include <stdint.h>
#include <cairo/cairo.h>

#include <gtk/gtk.h>
#include <gdk/gdkkeysyms.h>

#include "gtk_pianokeyboard.h"

#define PIANO_KEYBOARD_DEFAULT_WIDTH 730
#define PIANO_KEYBOARD_DEFAULT_HEIGHT 70

enum {
        NOTE_ON_SIGNAL,
        NOTE_OFF_SIGNAL,
        REST_SIGNAL,
        LAST_SIGNAL
};

static guint    piano_keyboard_signals[LAST_SIGNAL] = { 0 };

static void
draw_keyboard_cue(PianoKeyboard *pk, cairo_t* cr)
{
        int             w = pk->notes[0].w;
        int             h = pk->notes[0].h;

        int             first_note_in_lower_row = (pk->octave + 5) * 12;
        int             last_note_in_lower_row = (pk->octave + 6) * 12 - 1;
        int             first_note_in_higher_row = (pk->octave + 6) * 12;
        int             last_note_in_higher_row = (pk->octave + 7) * 12 + 4;

        cairo_set_source_rgb (cr, 1.0f, 0.0f, 0.0f);
        cairo_move_to (cr, pk->notes[first_note_in_lower_row].x + 3, h - 6);
        cairo_line_to (cr, pk->notes[last_note_in_lower_row].x + w - 3, h - 6);
        cairo_stroke (cr);

        cairo_set_source_rgb (cr, 0.0f, 0.0f, 1.0f);
        cairo_move_to (cr, pk->notes[first_note_in_higher_row].x + 3, h - 9);
        cairo_line_to (cr, pk->notes[last_note_in_higher_row].x + w - 3, h - 9);
        cairo_stroke (cr);
}

static void
queue_note_draw (PianoKeyboard* pk, int note)
{
        GdkWindow* w = GTK_WIDGET(pk)->window;

        if (w) {
                GdkRectangle r;

                r.x = pk->notes[note].x;
                r.y = 0;
                r.width = pk->notes[note].w;
                r.height = pk->notes[note].h;

                gdk_window_invalidate_rect (w, &r, TRUE);
        }
}

static void
draw_note(PianoKeyboard *pk, cairo_t* cr, int note)
{
        int             is_white = pk->notes[note].white;

        int             x = pk->notes[note].x;
        int             w = pk->notes[note].w;
        int             h = pk->notes[note].h;

        if (pk->notes[note].pressed || pk->notes[note].sustained) {
                if (is_white) {
                        cairo_set_source_rgb (cr, 0.60f, 0.60f, 0.60f);
                } else {
                        cairo_set_source_rgb (cr, 0.50f, 0.50f, 0.50f);
                }
        } else {
                if (is_white) {
                        cairo_set_source_rgb (cr, 1.0f, 1.0f, 1.0f);
                } else {
                        cairo_set_source_rgb (cr, 0.0f, 0.0f, 0.0f);
                }
        }

        cairo_set_line_width (cr, 1.0);

        cairo_rectangle (cr, x, 0, w, h);
        cairo_fill (cr);

        cairo_set_source_rgb(cr, 0.0f, 0.0f, 0.0f); /* black outline */
        cairo_rectangle (cr, x, 0, w, h);
        cairo_stroke (cr);

        if (pk->enable_keyboard_cue) {
                draw_keyboard_cue (pk, cr);
        }

        /* We need to redraw black keys that partially obscure the white one. */
        if (note < NNOTES - 2 && !pk->notes[note + 1].white) {
                draw_note(pk, cr, note + 1);
        }

        if (note > 0 && !pk->notes[note - 1].white) {
                draw_note(pk, cr, note - 1);
        }
}

static int
press_key(PianoKeyboard *pk, int key)
{
        assert(key >= 0);
        assert(key < NNOTES);

        pk->maybe_stop_sustained_notes = 0;

        /* This is for keyboard autorepeat protection. */
        if (pk->notes[key].pressed)
                return 0;

        if (pk->sustain_new_notes)
                pk->notes[key].sustained = 1;
        else
                pk->notes[key].sustained = 0;

        if (pk->monophonic && pk->last_key != key) {
                pk->notes[pk->last_key].pressed   = 0;
                pk->notes[pk->last_key].sustained = 0;
                queue_note_draw(pk, pk->last_key);
        }
        pk->last_key = key;

        pk->notes[key].pressed = 1;

        g_signal_emit_by_name(GTK_WIDGET(pk), "note-on", key);
        queue_note_draw(pk, key);

        return 1;
}

static int
release_key(PianoKeyboard *pk, int key)
{
        assert(key >= 0);
        assert(key < NNOTES);

        pk->maybe_stop_sustained_notes = 0;

        if (!pk->notes[key].pressed)
                return 0;

        if (pk->sustain_new_notes)
                pk->notes[key].sustained = 1;

        pk->notes[key].pressed = 0;

        if (pk->notes[key].sustained)
                return 0;

        g_signal_emit_by_name(GTK_WIDGET(pk), "note-off", key);
        queue_note_draw(pk, key);

        return 1;
}

static void
rest (PianoKeyboard* pk)
{
        g_signal_emit_by_name(GTK_WIDGET(pk), "rest");
}

static void
stop_unsustained_notes(PianoKeyboard *pk)
{
        int             i;

        for (i = 0; i < NNOTES; i++) {
                if (pk->notes[i].pressed && !pk->notes[i].sustained) {
                        pk->notes[i].pressed = 0;
                        g_signal_emit_by_name(GTK_WIDGET(pk), "note-off", i);
                        queue_note_draw(pk, i);
                }
        }
}

static void
stop_sustained_notes(PianoKeyboard *pk)
{
        int             i;

        for (i = 0; i < NNOTES; i++) {
                if (pk->notes[i].sustained) {
                        pk->notes[i].pressed = 0;
                        pk->notes[i].sustained = 0;
                        g_signal_emit_by_name(GTK_WIDGET(pk), "note-off", i);
                        queue_note_draw(pk, i);
                }
        }
}

static int
key_binding(PianoKeyboard *pk, const char *key)
{
        gpointer notused, note;
        gboolean found;

        assert(pk->key_bindings != NULL);

        found = g_hash_table_lookup_extended(pk->key_bindings, key, &notused, &note);

        if (!found)
                return -1;

        return (intptr_t)note;
}

static void
bind_key(PianoKeyboard *pk, const char *key, int note)
{
        assert(pk->key_bindings != NULL);

        g_hash_table_insert(pk->key_bindings, (const gpointer)key, (gpointer)((intptr_t)note));
}

static void
clear_notes(PianoKeyboard *pk)
{
        assert(pk->key_bindings != NULL);

        g_hash_table_remove_all(pk->key_bindings);
}

static void
bind_keys_qwerty(PianoKeyboard *pk)
{
        clear_notes(pk);

        bind_key(pk, "space", 128);

        /* Lower keyboard row - "zxcvbnm". */
        bind_key(pk, "z", 12);  /* C0 */
        bind_key(pk, "s", 13);
        bind_key(pk, "x", 14);
        bind_key(pk, "d", 15);
        bind_key(pk, "c", 16);
        bind_key(pk, "v", 17);
        bind_key(pk, "g", 18);
        bind_key(pk, "b", 19);
        bind_key(pk, "h", 20);
        bind_key(pk, "n", 21);
        bind_key(pk, "j", 22);
        bind_key(pk, "m", 23);

        /* Upper keyboard row, first octave - "qwertyu". */
        bind_key(pk, "q", 24);
        bind_key(pk, "2", 25);
        bind_key(pk, "w", 26);
        bind_key(pk, "3", 27);
        bind_key(pk, "e", 28);
        bind_key(pk, "r", 29);
        bind_key(pk, "5", 30);
        bind_key(pk, "t", 31);
        bind_key(pk, "6", 32);
        bind_key(pk, "y", 33);
        bind_key(pk, "7", 34);
        bind_key(pk, "u", 35);

        /* Upper keyboard row, the rest - "iop". */
        bind_key(pk, "i", 36);
        bind_key(pk, "9", 37);
        bind_key(pk, "o", 38);
        bind_key(pk, "0", 39);
        bind_key(pk, "p", 40);
}

static void
bind_keys_qwertz(PianoKeyboard *pk)
{
        bind_keys_qwerty(pk);

        /* The only difference between QWERTY and QWERTZ is that the "y" and "z" are swapped together. */
        bind_key(pk, "y", 12);
        bind_key(pk, "z", 33);
}

static void
bind_keys_azerty(PianoKeyboard *pk)
{
        clear_notes(pk);

        bind_key(pk, "space", 128);

        /* Lower keyboard row - "wxcvbn,". */
        bind_key(pk, "w", 12);  /* C0 */
        bind_key(pk, "s", 13);
        bind_key(pk, "x", 14);
        bind_key(pk, "d", 15);
        bind_key(pk, "c", 16);
        bind_key(pk, "v", 17);
        bind_key(pk, "g", 18);
        bind_key(pk, "b", 19);
        bind_key(pk, "h", 20);
        bind_key(pk, "n", 21);
        bind_key(pk, "j", 22);
        bind_key(pk, "comma", 23);

        /* Upper keyboard row, first octave - "azertyu". */
        bind_key(pk, "a", 24);
        bind_key(pk, "eacute", 25);
        bind_key(pk, "z", 26);
        bind_key(pk, "quotedbl", 27);
        bind_key(pk, "e", 28);
        bind_key(pk, "r", 29);
        bind_key(pk, "parenleft", 30);
        bind_key(pk, "t", 31);
        bind_key(pk, "minus", 32);
        bind_key(pk, "y", 33);
        bind_key(pk, "egrave", 34);
        bind_key(pk, "u", 35);

        /* Upper keyboard row, the rest - "iop". */
        bind_key(pk, "i", 36);
        bind_key(pk, "ccedilla", 37);
        bind_key(pk, "o", 38);
        bind_key(pk, "agrave", 39);
        bind_key(pk, "p", 40);
}

static gint
keyboard_event_handler(GtkWidget *mk, GdkEventKey *event, gpointer ignored)
{
        int             note;
        char            *key;
        guint           keyval;
        GdkKeymapKey    kk;
        PianoKeyboard   *pk = PIANO_KEYBOARD(mk);

        (void) ignored;

        /* We're not using event->keyval, because we need keyval with level set to 0.
           E.g. if user holds Shift and presses '7', we want to get a '7', not '&'. */
        kk.keycode = event->hardware_keycode;
        kk.level = 0;
        kk.group = 0;

        keyval = gdk_keymap_lookup_key(NULL, &kk);

        key = gdk_keyval_name(gdk_keyval_to_lower(keyval));

        if (key == NULL) {
                g_message("gtk_keyval_name() returned NULL; please report this.");
                return FALSE;
        }

        note = key_binding(pk, key);

        if (note < 0) {
                /* Key was not bound.  Maybe it's one of the keys handled in jack-keyboard.c. */
                return FALSE;
        }

        if (note == 128) {
                if (event->type == GDK_KEY_RELEASE) {
                        rest (pk);
                }

                return TRUE;
        }

        note += pk->octave * 12;

        assert(note >= 0);
        assert(note < NNOTES);

        if (event->type == GDK_KEY_PRESS) {
                press_key(pk, note);

        } else if (event->type == GDK_KEY_RELEASE) {
                release_key(pk, note);
        }

        return TRUE;
}

static int
get_note_for_xy(PianoKeyboard *pk, int x, int y)
{
        int             height = GTK_WIDGET(pk)->allocation.height;
        int             note;

        if (y <= height / 2) {
                for (note = 0; note < NNOTES - 1; note++) {
                        if (pk->notes[note].white)
                                continue;

                        if (x >= pk->notes[note].x && x <= pk->notes[note].x + pk->notes[note].w)
                                return note;
                }
        }

        for (note = 0; note < NNOTES - 1; note++) {
                if (!pk->notes[note].white)
                        continue;

                if (x >= pk->notes[note].x && x <= pk->notes[note].x + pk->notes[note].w)
                        return note;
        }

        return -1;
}

static gboolean
mouse_button_event_handler(PianoKeyboard *pk, GdkEventButton *event, gpointer ignored)
{
        int             x = event->x;
        int             y = event->y;

        int             note = get_note_for_xy(pk, x, y);

        (void) ignored;

        if (event->button != 1)
                return TRUE;

        if (event->type == GDK_BUTTON_PRESS) {
                /* This is possible when you make the window a little wider and then click
                   on the grey area. */
                if (note < 0) {
                        return TRUE;
                }

                if (pk->note_being_pressed_using_mouse >= 0)
                        release_key(pk, pk->note_being_pressed_using_mouse);

                press_key(pk, note);
                pk->note_being_pressed_using_mouse = note;

        } else if (event->type == GDK_BUTTON_RELEASE) {
                if (note >= 0) {
                        release_key(pk, note);

                } else {
                        if (pk->note_being_pressed_using_mouse >= 0)
                                release_key(pk, pk->note_being_pressed_using_mouse);
                }

                pk->note_being_pressed_using_mouse = -1;

        }

        return TRUE;
}

static gboolean
mouse_motion_event_handler(PianoKeyboard *pk, GdkEventMotion *event, gpointer ignored)
{
        int             note;

        (void) ignored;

        if ((event->state & GDK_BUTTON1_MASK) == 0)
                return TRUE;

        note = get_note_for_xy(pk, event->x, event->y);

        if (note != pk->note_being_pressed_using_mouse && note >= 0) {

                if (pk->note_being_pressed_using_mouse >= 0)
                        release_key(pk, pk->note_being_pressed_using_mouse);
                press_key(pk, note);
                pk->note_being_pressed_using_mouse = note;
        }

        return TRUE;
}

static gboolean
piano_keyboard_expose(GtkWidget *widget, GdkEventExpose *event)
{
        int i;
        PianoKeyboard *pk = PIANO_KEYBOARD(widget);
        cairo_t* cr = gdk_cairo_create (GDK_DRAWABLE (GTK_WIDGET(pk)->window));

        gdk_cairo_region (cr, event->region);
        cairo_clip (cr);

        for (i = 0; i < NNOTES; i++) {
                GdkRectangle r;

                r.x = pk->notes[i].x;
                r.y = 0;
                r.width = pk->notes[i].w;
                r.height = pk->notes[i].h;

                switch (gdk_region_rect_in (event->region, &r)) {
                case GDK_OVERLAP_RECTANGLE_PART:
                case GDK_OVERLAP_RECTANGLE_IN:
                        draw_note (pk, cr, i);
                        break;
                default:
                        break;
                }
        }

        cairo_destroy (cr);

        return TRUE;
}

static void
piano_keyboard_size_request(GtkWidget* w, GtkRequisition *requisition)
{
        (void) w;

        requisition->width = PIANO_KEYBOARD_DEFAULT_WIDTH;
        requisition->height = PIANO_KEYBOARD_DEFAULT_HEIGHT;
}

static void
recompute_dimensions(PianoKeyboard *pk)
{
        int             number_of_white_keys = (NNOTES - 1) * (7.0 / 12.0);

        int             key_width;
        int             black_key_width;
        int             useful_width;

        int             note;
        int             white_key = 0;
        int             note_in_octave;

        int             width = GTK_WIDGET(pk)->allocation.width;
        int             height = GTK_WIDGET(pk)->allocation.height;

        key_width = width / number_of_white_keys;
        black_key_width = key_width * 0.8;
        useful_width = number_of_white_keys * key_width;
        pk->widget_margin = (width - useful_width) / 2;

        for (note = 0, white_key = 0; note < NNOTES - 2; note++) {
                note_in_octave = note % 12;

                if (note_in_octave == 1 || note_in_octave == 3 || note_in_octave == 6 ||
                        note_in_octave == 8 || note_in_octave == 10) {

                        /* This note is black key. */
                        pk->notes[note].x = pk->widget_margin + white_key * key_width - black_key_width / 2;
                        pk->notes[note].w = black_key_width;
                        pk->notes[note].h = height / 2;
                        pk->notes[note].white = 0;

                        continue;
                }

                /* This note is white key. */
                pk->notes[note].x = pk->widget_margin + white_key * key_width;
                pk->notes[note].w = key_width;
                pk->notes[note].h = height;
                pk->notes[note].white = 1;

                white_key++;
        }
}

static void
piano_keyboard_size_allocate(GtkWidget *widget, GtkAllocation *allocation)
{
        /* XXX: Are these two needed? */
        g_return_if_fail(widget != NULL);
        g_return_if_fail(allocation != NULL);

        widget->allocation = *allocation;

        recompute_dimensions(PIANO_KEYBOARD(widget));

        if (GTK_WIDGET_REALIZED(widget)) {
                gdk_window_move_resize (widget->window, allocation->x, allocation->y, allocation->width, allocation->height);
        }
}

static void
piano_keyboard_class_init(PianoKeyboardClass *klass)
{
        GtkWidgetClass  *widget_klass;

        /* Set up signals. */
        piano_keyboard_signals[NOTE_ON_SIGNAL] = g_signal_new ("note-on",
                G_TYPE_FROM_CLASS (klass), (GSignalFlags)(G_SIGNAL_RUN_FIRST | G_SIGNAL_ACTION),
                0, NULL, NULL, g_cclosure_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);

        piano_keyboard_signals[NOTE_OFF_SIGNAL] = g_signal_new ("note-off",
                G_TYPE_FROM_CLASS (klass), (GSignalFlags)(G_SIGNAL_RUN_FIRST | G_SIGNAL_ACTION),
                0, NULL, NULL, g_cclosure_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);

        piano_keyboard_signals[REST_SIGNAL] = g_signal_new ("rest",
                G_TYPE_FROM_CLASS (klass), (GSignalFlags)(G_SIGNAL_RUN_FIRST | G_SIGNAL_ACTION),
                0, NULL, NULL, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);

        widget_klass = (GtkWidgetClass*) klass;

        widget_klass->expose_event = piano_keyboard_expose;
        widget_klass->size_request = piano_keyboard_size_request;
        widget_klass->size_allocate = piano_keyboard_size_allocate;
}

static void
piano_keyboard_init(GtkWidget *mk)
{
        gtk_widget_add_events(mk, GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK);

        g_signal_connect(G_OBJECT(mk), "button-press-event", G_CALLBACK(mouse_button_event_handler), NULL);
        g_signal_connect(G_OBJECT(mk), "button-release-event", G_CALLBACK(mouse_button_event_handler), NULL);
        g_signal_connect(G_OBJECT(mk), "motion-notify-event", G_CALLBACK(mouse_motion_event_handler), NULL);
        g_signal_connect(G_OBJECT(mk), "key-press-event", G_CALLBACK(keyboard_event_handler), NULL);
        g_signal_connect(G_OBJECT(mk), "key-release-event", G_CALLBACK(keyboard_event_handler), NULL);
}

GType
piano_keyboard_get_type(void)
{
        static GType mk_type = 0;

        if (!mk_type) {
                static const GTypeInfo mk_info = {
                        sizeof(PianoKeyboardClass),
                        NULL, /* base_init */
                        NULL, /* base_finalize */
                        (GClassInitFunc) piano_keyboard_class_init,
                        NULL, /* class_finalize */
                        NULL, /* class_data */
                        sizeof (PianoKeyboard),
                        0,    /* n_preallocs */
                        (GInstanceInitFunc) piano_keyboard_init,
                        0,    /* value_table */
                };

                mk_type = g_type_register_static(GTK_TYPE_DRAWING_AREA, "PianoKeyboard", &mk_info, (GTypeFlags)0);
        }

        return mk_type;
}

GtkWidget *
piano_keyboard_new(void)
{
        GtkWidget *widget = (GtkWidget*)gtk_type_new(piano_keyboard_get_type());

        PianoKeyboard *pk = PIANO_KEYBOARD(widget);

        pk->maybe_stop_sustained_notes = 0;
        pk->sustain_new_notes = 0;
        pk->enable_keyboard_cue = 0;
        pk->octave = 4;
        pk->note_being_pressed_using_mouse = -1;
        pk->last_key = 0;
        pk->monophonic = FALSE;
        memset((void *)pk->notes, 0, sizeof(struct PKNote) * NNOTES);
        pk->key_bindings = g_hash_table_new(g_str_hash, g_str_equal);
        bind_keys_qwerty(pk);

        return widget;
}

void
piano_keyboard_set_keyboard_cue(PianoKeyboard *pk, int enabled)
{
        pk->enable_keyboard_cue = enabled;
}

void
piano_keyboard_set_monophonic(PianoKeyboard *pk, gboolean monophonic)
{
        pk->monophonic = monophonic;
}

void
piano_keyboard_sustain_press(PianoKeyboard *pk)
{
        if (!pk->sustain_new_notes) {
                pk->sustain_new_notes = 1;
                pk->maybe_stop_sustained_notes = 1;
        }
}

void
piano_keyboard_sustain_release(PianoKeyboard *pk)
{
        if (pk->maybe_stop_sustained_notes)
                stop_sustained_notes(pk);

        pk->sustain_new_notes = 0;
}

void
piano_keyboard_set_note_on(PianoKeyboard *pk, int note)
{
        if (pk->notes[note].pressed == 0) {
                pk->notes[note].pressed = 1;
                queue_note_draw (pk, note);
        }
}

void
piano_keyboard_set_note_off(PianoKeyboard *pk, int note)
{
        if (pk->notes[note].pressed || pk->notes[note].sustained) {
                pk->notes[note].pressed = 0;
                pk->notes[note].sustained = 0;
                queue_note_draw (pk, note);
        }
}

void
piano_keyboard_set_octave(PianoKeyboard *pk, int octave)
{
        stop_unsustained_notes(pk);
        pk->octave = octave;
        gtk_widget_queue_draw(GTK_WIDGET(pk));
}

gboolean
piano_keyboard_set_keyboard_layout(PianoKeyboard *pk, const char *layout)
{
        assert(layout);

        if (!g_ascii_strcasecmp(layout, "QWERTY")) {
                bind_keys_qwerty(pk);

        } else if (!g_ascii_strcasecmp(layout, "QWERTZ")) {
                bind_keys_qwertz(pk);

        } else if (!g_ascii_strcasecmp(layout, "AZERTY")) {
                bind_keys_azerty(pk);

        } else {
                /* Unknown layout name. */
                return TRUE;
        }

        return FALSE;
}