src/calf/ctl_keyboard.h

   1 /* Calf DSP Library
   2  * Barely started keyboard widget. Planned to be usable as
   3  * a ruler for curves, and possibly as input widget in future
   4  * as well (that's what event sink interface is for, at least).
   5  *
   6  * Copyright (C) 2008 Krzysztof Foltman
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General
  19  * Public License along with this program; if not, write to the
  20  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  21  * Boston, MA 02111-1307, USA.
  22  */
  23 #ifndef CALF_CTL_KEYBOARD_H
  24 #define CALF_CTL_KEYBOARD_H
  25
  26 #include <gtk/gtk.h>
  27
  28 G_BEGIN_DECLS
  29
  30 #define CALF_TYPE_KEYBOARD          (calf_keyboard_get_type())
  31 #define CALF_KEYBOARD(obj)          (G_TYPE_CHECK_INSTANCE_CAST ((obj), CALF_TYPE_KEYBOARD, CalfKeyboard))
  32 #define CALF_IS_KEYBOARD(obj)       (G_TYPE_CHECK_INSTANCE_TYPE ((obj), CALF_TYPE_KEYBOARD))
  33 #define CALF_KEYBOARD_CLASS(klass)  (G_TYPE_CHECK_CLASS_CAST ((klass),  CALF_TYPE_KEYBOARD, CalfKeyboardClass))
  34 #define CALF_IS_KEYBOARD_CLASS(obj) (G_TYPE_CHECK_CLASS_TYPE ((klass),  CALF_TYPE_KEYBOARD))
  35
  36 /// Instance-specific data for CalfKeyboard
  37 struct CalfKeyboard
  38 {
  39     /// Structure with information needed for drawing a single key
  40     struct KeyInfo
  41     {
  42         double x; ///< X coordinate of the top-left point of the key
  43         double y; ///< Y coordinate of the top-left point of the key
  44         double width; ///< key width
  45         double height; ///< key height
  46         int note; ///< MIDI note number
  47         bool black; ///< true if it's a black key, false if it's a white key
  48     };
  49
  50     /// Set of user-defined callbacks for customizing display and operation of CalfKeyboard
  51     struct EventSink
  52     {
  53         /// (will be) called on attachment of sink to CalfKeyboard object
  54         virtual void set_instance(CalfKeyboard *kb)=0;
  55         /// called before drawing key interior
  56         /// @retval true do not draw the key
  57         virtual bool pre_draw(cairo_t *c, KeyInfo &ki)=0;
  58         /// @retval true do not draw the outline
  59         /// called before drawing key outline of white keys
  60         virtual bool pre_draw_outline(cairo_t *c, KeyInfo &ki)=0;
  61         /// called after key is drawn using standard method (but not if drawing is skipped)
  62         virtual void post_draw(cairo_t *c, KeyInfo &ki)=0;
  63         /// called after key is drawn
  64         virtual void post_all(cairo_t *c)=0;
  65         /// key was pressed
  66         virtual void note_on(int note, int vel) = 0;
  67         /// key was released
  68         virtual void note_off(int note) = 0;
  69     };
  70
  71     /// Null implementation of CalfKeyboard::EventSink
  72     struct EventAdapter: public EventSink
  73     {
  74         CalfKeyboard *kb;
  75         virtual void set_instance(CalfKeyboard *_kb) { kb = _kb; }
  76         virtual bool pre_draw(cairo_t *c, KeyInfo &ki) { return false; }
  77         virtual bool pre_draw_outline(cairo_t *c, KeyInfo &ki) { return false; }
  78         virtual void post_draw(cairo_t *c, KeyInfo &ki) {}
  79         virtual void post_all(cairo_t *c) {}
  80         virtual void note_on(int note, int vel) {}
  81         virtual void note_off(int note) {}
  82     };
  83
  84     /// Debug/example implementation of CalfKeyboard::EventSink
  85     struct EventTester: public EventAdapter
  86     {
  87         virtual bool pre_draw(cairo_t *c, KeyInfo &ki) { if (ki.note == 60) cairo_set_source_rgb(c, 1.0, 1.0, 0.5); return false; }
  88         virtual void post_draw(cairo_t *c, KeyInfo &ki) {
  89             if (ki.note % 12 != 0 && ki.note % 12 != 3 && ki.note % 12 != 7)
  90                 return;
  91             cairo_rectangle(c, ki.x + ki.width / 2 - 2, ki.y + ki.height - 8, 4, 4);
  92             if (ki.black)
  93                 cairo_set_source_rgb(c, 1.0, 1.0, 1.0);
  94             else
  95                 cairo_set_source_rgb(c, 0.0, 0.0, 0.0);
  96             cairo_fill(c);
  97         }
  98         virtual void note_on(int note, int vel) { g_message("note on %d %d", note, vel); }
  99         virtual void note_off(int note) { g_message("note off %d", note); }
 100     };
 101
 102     /// Parent instance members
 103     GtkWidget parent;
 104     /// Range (number of white keys = number of octaves * 7 + 1)
 105     int nkeys;
 106     EventSink *sink;
 107     /// The note currently pressed via mouse selection
 108     int last_key;
 109     /// If true, the keyboard accepts mouse clicks and keys
 110     bool interactive;
 111 };
 112
 113 /// Class-specific data for CalfKeyboard
 114 struct CalfKeyboardClass
 115 {
 116     /// Parent class members
 117     GtkWidgetClass parent_class;
 118 };
 119
 120 /// Create new keyboard object;
 121 extern GtkWidget *calf_keyboard_new();
 122
 123 /// Return a GType for CalfKeyboard
 124 extern GType calf_keyboard_get_type();
 125
 126 G_END_DECLS
 127
 128 #endif
 129