Import Upstream version 0.2.0+hg20110905r195

1 files changed, 919 insertions, 0 deletions

diff --git a/gtkknob.c b/gtkknob.c
new file mode 100644
index 0000000..d64a467
--- /dev/null
+++ b/gtkknob.c
@@ -0,0 +1,919 @@
+/*****************************************************************************
+ *
+ * Most of this code comes from gAlan 0.2.0, copyright (C) 1999
+ * Tony Garnock-Jones, with modifications from Sean Bolton,
+ * copyright (C) 2004, William Weston copyright (C) 2007,
+ * Pete Shorthose copyright (C) 2007, and Tomasz Moń,
+ * copyright (C) 2009
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *****************************************************************************/
+
+#include <math.h>
+#include <gtk/gtk.h>
+#include <gdk/gdkkeysyms.h>
+#include "gtkknob.h"
+
+
+#ifndef M_PI
+# define M_PI		3.14159265358979323846	/* pi */
+#endif
+#ifndef M_1_PI
+# define M_1_PI		0.31830988618379067154	/* 1/pi */
+#endif
+
+
+#define SCROLL_DELAY_LENGTH	250
+#define KNOB_SIZE		32	/* this should really be read from the knob image */
+
+#define STATE_IDLE		0
+#define STATE_PRESSED		1
+#define STATE_DRAGGING		2
+
+static void gtk_knob_class_init(GtkKnobClass *klass);
+static void gtk_knob_init(GtkKnob *knob);
+static void gtk_knob_destroy(GtkObject *object);
+static void gtk_knob_realize(GtkWidget *widget);
+static void gtk_knob_size_request(GtkWidget *widget, GtkRequisition *requisition);
+static void gtk_knob_size_allocate(GtkWidget *widget, GtkAllocation *allocation);
+static gint gtk_knob_expose(GtkWidget *widget, GdkEventExpose *event);
+static gint gtk_knob_scroll(GtkWidget *widget, GdkEventScroll *event);
+static gint gtk_knob_button_press(GtkWidget *widget, GdkEventButton *event);
+static gint gtk_knob_button_release(GtkWidget *widget, GdkEventButton *event);
+static gint gtk_knob_key_press(GtkWidget *widget, GdkEventKey *event);
+static gint gtk_knob_motion_notify(GtkWidget *widget, GdkEventMotion *event);
+static gint gtk_knob_timer(GtkKnob *knob);
+
+static void gtk_knob_update_mouse_update(GtkKnob *knob);
+static void gtk_knob_update_mouse(GtkKnob *knob, gint x, gint y, gboolean step);
+static void gtk_knob_update(GtkKnob *knob);
+static void gtk_knob_adjustment_changed(GtkAdjustment *adjustment, gpointer data);
+static void gtk_knob_adjustment_value_changed(GtkAdjustment *adjustment, gpointer data);
+
+/* Local data */
+
+static GtkWidgetClass *parent_class = NULL;
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_get_type()
+ *
+ *****************************************************************************/
+GType
+gtk_knob_get_type(void) {
+    static GType knob_type = 0;
+
+    if (!knob_type) {
+	static const GTypeInfo knob_info = {
+	    sizeof (GtkKnobClass),
+            NULL,
+	    NULL,
+	    (GClassInitFunc) gtk_knob_class_init,
+	    NULL,
+	    NULL,
+	    sizeof (GtkKnob),
+	    0,
+	    (GInstanceInitFunc) gtk_knob_init,
+	};
+	knob_type = g_type_register_static (GTK_TYPE_WIDGET, "GtkKnob", &knob_info, 0);
+    }
+
+    return knob_type;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_class_init()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_class_init (GtkKnobClass *klass) {
+    GtkObjectClass *object_class;
+    GtkWidgetClass *widget_class;
+
+    object_class = (GtkObjectClass*) klass;
+    widget_class = (GtkWidgetClass*) klass;
+
+    parent_class = g_type_class_peek_parent(klass);
+
+    object_class->destroy = gtk_knob_destroy;
+
+    widget_class->realize              = gtk_knob_realize;
+    widget_class->expose_event         = gtk_knob_expose;
+    widget_class->size_request         = gtk_knob_size_request;
+    widget_class->size_allocate        = gtk_knob_size_allocate;
+    widget_class->scroll_event         = gtk_knob_scroll;
+    widget_class->button_press_event   = gtk_knob_button_press;
+    widget_class->button_release_event = gtk_knob_button_release;
+    widget_class->key_press_event      = gtk_knob_key_press;
+    widget_class->motion_notify_event  = gtk_knob_motion_notify;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_init()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_init (GtkKnob *knob) {
+    knob->policy     = GTK_UPDATE_CONTINUOUS;
+    knob->state      = STATE_IDLE;
+    knob->saved_x    = 0;
+    knob->saved_y    = 0;
+    knob->timer      = 0;
+    knob->anim       = NULL;
+    knob->mask       = NULL;
+    knob->mask_gc    = NULL;
+    knob->red_gc     = NULL;
+    knob->old_value  = 0.0;
+    knob->old_lower  = 0.0;
+    knob->old_upper  = 0.0;
+    knob->adjustment = NULL;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_new()
+ *
+ *****************************************************************************/
+GtkWidget *
+gtk_knob_new(GtkAdjustment *adjustment, GtkKnobAnim *anim) {
+    GtkKnob *knob;
+
+    g_return_val_if_fail (anim != NULL, NULL);
+    g_return_val_if_fail (GDK_IS_PIXBUF (anim->pixbuf), NULL);
+
+    knob = g_object_new (gtk_knob_get_type (), NULL);
+
+    gtk_knob_set_animation (knob, anim);
+
+    if (!adjustment) {
+	adjustment = (GtkAdjustment*) gtk_adjustment_new (0.0, 0.0, 0.0,
+							  0.0, 0.0, 0.0);
+    }
+
+    gtk_knob_set_adjustment (knob, adjustment);
+
+    return GTK_WIDGET (knob);
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_destroy()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_destroy(GtkObject *object) {
+    GtkKnob *knob;
+
+    g_return_if_fail (object != NULL);
+    g_return_if_fail (GTK_IS_KNOB (object));
+
+    knob = GTK_KNOB (object);
+
+    gtk_knob_set_adjustment (knob, NULL);
+    /* FIXME: needs ref counting for automatic GtkKnobAnim cleanup
+       if (knob->anim) {
+	   gtk_knob_anim_unref (knob->anim);
+	   knob->anim = NULL;
+       }
+    */
+
+    if (knob->mask) {
+	g_object_unref (knob->mask);
+	knob->mask = NULL;
+    }
+
+    if (knob->mask_gc) {
+	g_object_unref (knob->mask_gc);
+	knob->mask_gc = NULL;
+    }
+    if (knob->red_gc) {
+	g_object_unref (knob->red_gc);
+	knob->red_gc = NULL;
+    }
+
+    if (GTK_OBJECT_CLASS (parent_class)->destroy) {
+	(*GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_get_adjustment()
+ *
+ *****************************************************************************/
+GtkAdjustment*
+gtk_knob_get_adjustment(GtkKnob *knob) {
+
+    g_return_val_if_fail (knob != NULL, NULL);
+    g_return_val_if_fail (GTK_IS_KNOB (knob), NULL);
+
+    return knob->adjustment;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_set_update_policy()
+ *
+ *****************************************************************************/
+void
+gtk_knob_set_update_policy(GtkKnob *knob, GtkUpdateType policy) {
+
+    g_return_if_fail (knob != NULL);
+    g_return_if_fail (GTK_IS_KNOB (knob));
+
+    knob->policy = policy;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_set_adjustment()
+ *
+ *****************************************************************************/
+void
+gtk_knob_set_adjustment(GtkKnob *knob, GtkAdjustment *adjustment) {
+
+    g_return_if_fail (knob != NULL);
+    g_return_if_fail (GTK_IS_KNOB (knob));
+
+    if (knob->adjustment) {
+	g_signal_handlers_disconnect_matched(knob->adjustment,
+					     G_SIGNAL_MATCH_DATA,
+					     0, 0, NULL, NULL,
+					     knob);
+	g_object_unref (knob->adjustment);
+    }
+
+    knob->adjustment = adjustment;
+    if (adjustment) {
+        g_object_ref_sink (adjustment);
+
+        g_signal_connect (adjustment, "changed",
+    			G_CALLBACK(gtk_knob_adjustment_changed),
+			knob);
+	g_signal_connect (adjustment, "value_changed",
+			G_CALLBACK(gtk_knob_adjustment_value_changed),
+			knob);
+
+	knob->old_value = adjustment->value;
+	knob->old_lower = adjustment->lower;
+	knob->old_upper = adjustment->upper;
+
+	gtk_knob_update (knob);
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_realize()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_realize(GtkWidget *widget) {
+    GtkKnob *knob;
+    GdkWindowAttr attributes;
+    gint attributes_mask;
+    GdkColor color = { 0, 0xffff, 0, 0 };
+
+    g_return_if_fail (widget != NULL);
+    g_return_if_fail (GTK_IS_KNOB (widget));
+
+    GTK_WIDGET_SET_FLAGS (widget, GTK_REALIZED);
+    GTK_WIDGET_SET_FLAGS (widget, GTK_CAN_FOCUS);
+    knob = GTK_KNOB (widget);
+
+    attributes.x           = widget->allocation.x;
+    attributes.y           = widget->allocation.y;
+    attributes.width       = widget->allocation.width;
+    attributes.height      = widget->allocation.height;
+    attributes.wclass      = GDK_INPUT_OUTPUT;
+    attributes.window_type = GDK_WINDOW_CHILD;
+    attributes.event_mask  =
+	gtk_widget_get_events (widget) |
+	GDK_EXPOSURE_MASK | GDK_BUTTON_PRESS_MASK |
+	GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK |
+	GDK_POINTER_MOTION_HINT_MASK;
+    attributes.visual   = gtk_widget_get_visual (widget);
+    attributes.colormap = gtk_widget_get_colormap (widget);
+
+    attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;
+
+    widget->window = gdk_window_new (widget->parent->window,
+				     &attributes, attributes_mask);
+
+    widget->style = gtk_style_attach (widget->style, widget->window);
+
+    gdk_window_set_user_data (widget->window, widget);
+
+    gtk_style_set_background (widget->style, widget->window, GTK_STATE_NORMAL);
+
+    knob->mask_gc = gdk_gc_new (widget->window);
+    gdk_gc_copy (knob->mask_gc, widget->style->bg_gc[GTK_STATE_NORMAL]);
+    gdk_gc_set_clip_mask (knob->mask_gc, knob->mask);
+
+    knob->red_gc = gdk_gc_new (widget->window);
+    gdk_gc_copy (knob->red_gc, widget->style->bg_gc[GTK_STATE_NORMAL]);
+    gdk_colormap_alloc_color (attributes.colormap, &color, FALSE, TRUE);
+    gdk_gc_set_foreground (knob->red_gc, &color);
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_size_request()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_size_request (GtkWidget *widget, GtkRequisition *requisition) {
+
+    g_return_if_fail (widget != NULL);
+    g_return_if_fail (GTK_IS_KNOB (widget));
+
+    requisition->width  = GTK_KNOB (widget)->width;
+    requisition->height = GTK_KNOB (widget)->height;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_size_allocate()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_size_allocate (GtkWidget *widget, GtkAllocation *allocation) {
+    GtkKnob *knob;
+
+    g_return_if_fail (widget != NULL);
+    g_return_if_fail (GTK_IS_KNOB (widget));
+    g_return_if_fail (allocation != NULL);
+
+    widget->allocation = *allocation;
+    knob = GTK_KNOB (widget);
+
+    if (GTK_WIDGET_REALIZED (widget)) {
+	gdk_window_move_resize (widget->window,
+				allocation->x, allocation->y,
+				allocation->width, allocation->height);
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_expose()
+ *
+ *****************************************************************************/
+static gint
+gtk_knob_expose(GtkWidget *widget, GdkEventExpose *event) {
+    GtkKnob *knob;
+    gfloat dx, dy;
+    gint frames;
+
+    g_return_val_if_fail (widget != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_KNOB (widget), FALSE);
+    g_return_val_if_fail (event != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_ADJUSTMENT (GTK_KNOB (widget)->adjustment), FALSE);
+
+    if (event->count > 0)
+	return FALSE;
+
+    knob = GTK_KNOB (widget);
+
+    frames = ((knob->anim->width / knob->anim->frame_width) - 1);
+    dx = knob->adjustment->value - knob->adjustment->lower;	/* value, from 0 */
+    dy = knob->adjustment->upper - knob->adjustment->lower;	/* range */
+
+    dx = (int)(frames * dx / dy) * knob->width;  /* check this for height != width */
+
+    gdk_draw_pixbuf (widget->window, knob->mask_gc, knob->anim->pixbuf,
+		     dx, 0, 0, 0, knob->width, knob->height,
+		     GDK_RGB_DITHER_NONE, 0, 0);
+
+    if (GTK_WIDGET_HAS_FOCUS(widget)) {
+        gtk_paint_focus (widget->style, widget->window, widget->state,
+                         NULL, widget, NULL, 0, 0,
+                         widget->allocation.width, widget->allocation.height);
+    }
+
+    return FALSE;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_scroll()
+ *
+ *****************************************************************************/
+static gint
+gtk_knob_scroll(GtkWidget *widget, GdkEventScroll *event) {
+    GtkKnob *knob;
+
+    g_return_val_if_fail (widget != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_KNOB (widget), FALSE);
+    g_return_val_if_fail (event != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_ADJUSTMENT (GTK_KNOB (widget)->adjustment), FALSE);
+
+    knob = GTK_KNOB (widget);
+
+    switch (event->direction) {
+    case GDK_SCROLL_UP:
+	knob->adjustment->value += knob->adjustment->step_increment;
+	g_signal_emit_by_name (knob->adjustment, "value_changed");
+	break;
+    case GDK_SCROLL_DOWN:
+	knob->adjustment->value -= knob->adjustment->step_increment;
+	g_signal_emit_by_name (knob->adjustment, "value_changed");
+	break;
+    default:
+        break;
+    }
+
+    return FALSE;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_button_press()
+ *
+ *****************************************************************************/
+static gint
+gtk_knob_button_press(GtkWidget *widget, GdkEventButton *event) {
+    GtkKnob *knob;
+
+    g_return_val_if_fail (widget != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_KNOB (widget), FALSE);
+    g_return_val_if_fail (event != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_ADJUSTMENT (GTK_KNOB (widget)->adjustment), FALSE);
+
+    knob = GTK_KNOB (widget);
+
+    switch (knob->state) {
+    case STATE_IDLE:
+	switch (event->button) {
+	case 1:
+	case 3:
+	    if (!GTK_WIDGET_HAS_FOCUS(widget))
+	        gtk_widget_grab_focus(widget);
+	    knob->state   = STATE_PRESSED;
+	    knob->saved_x = event->x;
+	    knob->saved_y = event->y;
+	    break;
+	case 2:
+	    knob->adjustment->value = floor ((knob->adjustment->lower +
+					      knob->adjustment->upper + 1.0)
+					     * 0.5);
+	    g_signal_emit_by_name (knob->adjustment, "value_changed");
+	    break;
+	}
+	break;
+    }
+
+    return FALSE;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_button_release()
+ *
+ *****************************************************************************/
+static gint
+gtk_knob_button_release(GtkWidget *widget, GdkEventButton *event) {
+    GtkKnob *knob;
+
+    g_return_val_if_fail (widget != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_KNOB (widget), FALSE);
+    g_return_val_if_fail (event != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_ADJUSTMENT (GTK_KNOB (widget)->adjustment), FALSE);
+
+    knob = GTK_KNOB (widget);
+
+    switch (knob->state) {
+
+    case STATE_PRESSED:
+	knob->state = STATE_IDLE;
+	break;
+
+    case STATE_DRAGGING:
+	knob->state = STATE_IDLE;
+
+	switch (event->button) {
+	case 1:
+	case 3:
+	    if (knob->policy != GTK_UPDATE_CONTINUOUS
+		&& knob->old_value != knob->adjustment->value)
+	    {
+		g_signal_emit_by_name (knob->adjustment, "value_changed");
+	    }
+	    break;
+	}
+
+	break;
+    }
+
+    return FALSE;
+}
+
+static gint gtk_knob_key_press(GtkWidget *widget, GdkEventKey *event)
+{
+    GtkKnob *knob;
+
+    g_return_val_if_fail (widget != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_KNOB (widget), FALSE);
+    g_return_val_if_fail (event != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_ADJUSTMENT (GTK_KNOB (widget)->adjustment), FALSE);
+
+    knob = GTK_KNOB (widget);
+
+    switch (event->keyval) {
+
+    case GDK_Up:
+        if (GTK_WIDGET_HAS_FOCUS (widget))
+        {
+            gtk_adjustment_set_value (knob->adjustment,
+                                      knob->old_value + knob->adjustment->step_increment);
+            return TRUE;
+        }
+        return FALSE;
+
+    case GDK_Down:
+        if (GTK_WIDGET_HAS_FOCUS (widget))
+        {
+            gtk_adjustment_set_value (knob->adjustment,
+                                      knob->old_value - knob->adjustment->step_increment);
+            return TRUE;
+        }
+        return FALSE;
+    default:
+        break;
+    }
+
+    return GTK_WIDGET_CLASS (parent_class)->key_press_event (widget, event);
+}
+
+/*****************************************************************************
+ *
+ * gtk_knob_motion_notify()
+ *
+ *****************************************************************************/
+static gint
+gtk_knob_motion_notify(GtkWidget *widget, GdkEventMotion *event) {
+    GtkKnob *knob;
+    GdkModifierType mods;
+    gint x, y;
+
+    g_return_val_if_fail (widget != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_KNOB (widget), FALSE);
+    g_return_val_if_fail (event != NULL, FALSE);
+
+    knob = GTK_KNOB (widget);
+
+    x = event->x;
+    y = event->y;
+
+    if (event->is_hint || (event->window != widget->window)) {
+	gdk_window_get_pointer (widget->window, &x, &y, &mods);
+    }
+
+    switch (knob->state) {
+
+    case STATE_PRESSED:
+	knob->state = STATE_DRAGGING;
+	/* fall through */
+
+    case STATE_DRAGGING:
+	if (mods & GDK_BUTTON1_MASK) {
+	    gtk_knob_update_mouse (knob, x, y, TRUE);
+	    return TRUE;
+	}
+	else if (mods & GDK_BUTTON3_MASK) {
+	    gtk_knob_update_mouse (knob, x, y, FALSE);
+	    return TRUE;
+	}
+	break;
+    }
+
+    return FALSE;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_timer()
+ *
+ *****************************************************************************/
+static gint
+gtk_knob_timer(GtkKnob *knob) {
+
+    g_return_val_if_fail (knob != NULL, FALSE);
+    g_return_val_if_fail (GTK_IS_KNOB (knob), FALSE);
+    g_return_val_if_fail (GTK_IS_ADJUSTMENT (knob->adjustment), FALSE);
+
+    if (knob->policy == GTK_UPDATE_DELAYED) {
+	g_signal_emit_by_name (knob->adjustment, "value_changed");
+    }
+
+    /* don't keep running this timer */
+    return FALSE;
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_update_mouse_update()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_update_mouse_update(GtkKnob *knob) {
+    g_return_if_fail(GTK_IS_ADJUSTMENT (knob->adjustment));
+
+    if (knob->policy == GTK_UPDATE_CONTINUOUS) {
+	g_signal_emit_by_name (knob->adjustment, "value_changed");
+    }
+    else {
+	gtk_widget_queue_draw (GTK_WIDGET (knob));
+
+	if (knob->policy == GTK_UPDATE_DELAYED) {
+	    if (knob->timer) {
+		g_source_remove (knob->timer);
+	    }
+	    knob->timer = g_timeout_add (SCROLL_DELAY_LENGTH,
+					 (GSourceFunc) gtk_knob_timer,
+					 (gpointer) knob);
+	}
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_update_mouse()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_update_mouse(GtkKnob *knob, gint x, gint y, gboolean step) {
+    gfloat old_value, new_value, dv, dh;
+    gfloat angle;
+
+    g_return_if_fail (knob != NULL);
+    g_return_if_fail (GTK_IS_KNOB (knob));
+    g_return_if_fail (GTK_IS_ADJUSTMENT (knob->adjustment));
+
+    old_value = knob->adjustment->value;
+
+    angle = atan2f (-y + (knob->height >> 1), x - (knob->width >> 1));
+
+    /* inverted cartesian graphics coordinate system */
+    dv = knob->saved_y - y;
+    dh = x - knob->saved_x;
+    knob->saved_x = x;
+    knob->saved_y = y;
+
+    if ((x >= 0) && (x <= knob->width)) {
+        dh = 0;  /* dead zone */
+    } else {
+        angle = cosf (angle);
+        dh *= angle * angle;
+    }
+
+    new_value = knob->adjustment->value +
+                dv * (step ? knob->adjustment->step_increment : knob->adjustment->page_increment) +
+                dh * (knob->adjustment->upper -
+                knob->adjustment->lower) * 0.005; /* 0.005 == (1 / 200) */
+
+    new_value = MAX (MIN (new_value, knob->adjustment->upper),
+                     knob->adjustment->lower);
+
+    knob->adjustment->value = new_value;
+
+    if (knob->adjustment->value != old_value) {
+        gtk_knob_update_mouse_update (knob);
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_update()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_update(GtkKnob *knob) {
+    gfloat new_value;
+
+    g_return_if_fail (knob != NULL);
+    g_return_if_fail (GTK_IS_KNOB (knob));
+    g_return_if_fail (GTK_IS_ADJUSTMENT (knob->adjustment));
+
+    if (knob->adjustment->step_increment == 1) {
+	new_value = floor (knob->adjustment->value + 0.5);
+    }
+    else {
+	new_value = knob->adjustment->value;
+    }
+
+    if (new_value < knob->adjustment->lower) {
+	new_value = knob->adjustment->lower;
+    }
+
+    if (new_value > knob->adjustment->upper) {
+	new_value = knob->adjustment->upper;
+    }
+
+    if (new_value != knob->adjustment->value) {
+	knob->adjustment->value = new_value;
+	g_signal_emit_by_name (knob->adjustment, "value_changed");
+    }
+
+    gtk_widget_queue_draw (GTK_WIDGET (knob));
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_adjustment_changed()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_adjustment_changed(GtkAdjustment *adjustment, gpointer data) {
+    GtkKnob *knob;
+
+    g_return_if_fail (adjustment != NULL);
+    g_return_if_fail (data != NULL);
+
+    knob = GTK_KNOB (data);
+
+    if ((knob->old_value != adjustment->value) ||
+	(knob->old_lower != adjustment->lower) ||
+	(knob->old_upper != adjustment->upper))
+    {
+	gtk_knob_update (knob);
+
+	knob->old_value = adjustment->value;
+	knob->old_lower = adjustment->lower;
+	knob->old_upper = adjustment->upper;
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_adjustment_value_changed()
+ *
+ *****************************************************************************/
+static void
+gtk_knob_adjustment_value_changed (GtkAdjustment *adjustment, gpointer data) {
+    GtkKnob *knob;
+
+    g_return_if_fail (adjustment != NULL);
+    g_return_if_fail (data != NULL);
+
+    knob = GTK_KNOB (data);
+
+    if (knob->old_value != adjustment->value) {
+	gtk_knob_update (knob);
+	knob->old_value = adjustment->value;
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_set_animation()
+ *
+ *****************************************************************************/
+void
+gtk_knob_set_animation (GtkKnob *knob, GtkKnobAnim *anim) {
+    g_return_if_fail (knob != NULL);
+    g_return_if_fail (anim != NULL);
+    g_return_if_fail (GTK_IS_KNOB (knob));
+    g_return_if_fail (GDK_IS_PIXBUF (anim->pixbuf));
+
+    knob->anim   = (GtkKnobAnim *)anim;
+    knob->width  = anim->frame_width;
+    knob->height = anim->height;
+
+    if (GTK_WIDGET_REALIZED (knob)) {
+    	gtk_widget_queue_resize (GTK_WIDGET (knob));
+    }
+}
+
+
+/*****************************************************************************
+ *
+ * gtk_knob_animation_new_from_file()
+ *
+ *****************************************************************************/
+GtkKnobAnim *
+gtk_knob_animation_new_from_file(gchar *filename) {
+    GtkKnobAnim *anim;
+
+    anim = gtk_knob_animation_new_from_file_full (filename, -1, -1, KNOB_SIZE);
+    return anim;
+}
+
+/*****************************************************************************
+ *
+ * gtk_knob_animation_new_from_inline()
+ *
+ *****************************************************************************/
+GtkKnobAnim *
+gtk_knob_animation_new_from_inline(const guint8 *pixbuf) {
+    GtkKnobAnim *anim = g_new0 (GtkKnobAnim, 1);
+
+    g_return_val_if_fail((pixbuf != NULL), NULL);
+
+    anim->pixbuf = gdk_pixbuf_new_from_inline(-1, pixbuf, FALSE, NULL);
+    if (anim->pixbuf == NULL) {
+        g_free(anim);
+        return NULL;
+    }
+
+    anim->height      = gdk_pixbuf_get_height (anim->pixbuf);
+    anim->width       = gdk_pixbuf_get_width (anim->pixbuf);
+    anim->frame_width = anim->height;
+
+    return anim;
+}
+
+/*****************************************************************************
+ *
+ * gtk_knob_new_from_file_full()
+ *
+ * frame_width: overrides the frame width (to make rectangular frames)
+ * but doesn't affect the image size width and height cause optional
+ * scaling if not set to -1 when they are derived from the native
+ * image size.
+ *
+ * FIXME: account for any problems where (width % frame_width != 0)
+ *
+ *****************************************************************************/
+GtkKnobAnim *
+gtk_knob_animation_new_from_file_full(gchar *filename, gint frame_width,
+				      gint width, gint height) {
+    GtkKnobAnim *anim = g_new0 (GtkKnobAnim, 1);
+
+    g_return_val_if_fail ((filename != NULL), NULL);
+
+    GError *gerror = NULL;
+
+#if GTK_MINOR_VERSION < 10
+    if (!(anim->pixbuf = gdk_pixbuf_new_from_file (filename, &gerror))) {
+        g_error_free(gerror);
+        gerror = NULL;
+	return NULL;
+    }
+#else /* GTK_MINOR_VERSION >= 10 */
+    if (!(anim->pixbuf = gdk_pixbuf_new_from_file_at_size (filename, width,
+							   height, &gerror))) {
+        g_error_free(gerror);
+        gerror = NULL;
+	return NULL;
+    }
+#endif /* GTK_MINOR_VERSION < 10 */
+    else {
+	anim->height      = gdk_pixbuf_get_height (anim->pixbuf);
+	anim->width       = gdk_pixbuf_get_width (anim->pixbuf);
+	anim->frame_width = (frame_width != -1) ? frame_width : anim->height;
+    }
+
+    return anim;
+}
+
+/*****************************************************************************
+ *
+ * gtk_knob_animation_free()
+ *
+ *****************************************************************************/
+void
+gtk_knob_animation_free(GtkKnobAnim *anim) {
+    g_return_if_fail (anim != NULL);
+
+    if (anim->pixbuf)
+        g_object_unref (anim->pixbuf);
+
+    g_free (anim);
+}