MateHSV implementation (GtkHSV fork)

1 files changed, 1441 insertions, 0 deletions

diff --git a/libmate-desktop/mate-hsv.c b/libmate-desktop/mate-hsv.c
new file mode 100644
index 0000000..cacec6b
--- /dev/null
+++ b/libmate-desktop/mate-hsv.c
@@ -0,0 +1,1441 @@
+/* HSV color selector for GTK+
+ *
+ * Copyright (C) 1999 The Free Software Foundation
+ *
+ * Authors: Simon Budig <[email protected]> (original code)
+ *          Federico Mena-Quintero <[email protected]> (cleanup for GTK+)
+ *          Jonathan Blandford <[email protected]> (cleanup for GTK+)
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
+ * file for a list of people on the GTK+ Team.  See the ChangeLog
+ * files for a list of changes.  These files are distributed with
+ * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
+ *
+ * Modified to work internally in mate-desktop by Pablo Barciela 2019
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "mate-hsv.h"
+
+#include <math.h>
+#include <string.h>
+
+#include <gtk/gtk.h>
+
+#define I_(string) g_intern_static_string (string)
+
+/**
+ * SECTION:mate-hsv
+ * @Short_description: A “color wheel” widget
+ * @Title: MateHSV
+ *
+ * #MateHSV is the “color wheel” part of a complete color selector widget.
+ * It allows to select a color by determining its HSV components in an
+ * intuitive way. Moving the selection around the outer ring changes the hue,
+ * and moving the selection point inside the inner triangle changes value and
+ * saturation.
+ */
+
+/* Default width/height */
+#define DEFAULT_SIZE 100
+
+/* Default ring width */
+#define DEFAULT_RING_WIDTH 10
+
+
+/* Dragging modes */
+typedef enum {
+  DRAG_NONE,
+  DRAG_H,
+  DRAG_SV
+} DragMode;
+
+/* Private part of the MateHSV structure */
+struct _MateHSVPrivate
+{
+  /* Color value */
+  double h;
+  double s;
+  double v;
+  
+  /* Size and ring width */
+  int size;
+  int ring_width;
+  
+  /* Window for capturing events */
+  GdkWindow *window;
+  
+  /* Dragging mode */
+  DragMode mode;
+
+  guint focus_on_ring : 1;
+};
+
+
+/* Signal IDs */
+
+enum {
+  CHANGED,
+  MOVE,
+  LAST_SIGNAL
+};
+
+static void     mate_hsv_destroy              (GtkWidget          *widget);
+static void     mate_hsv_realize              (GtkWidget          *widget);
+static void     mate_hsv_unrealize            (GtkWidget          *widget);
+static void     mate_hsv_get_preferred_width  (GtkWidget          *widget,
+                                               gint               *minimum,
+                                               gint               *natural);
+static void     mate_hsv_get_preferred_height (GtkWidget          *widget,
+                                               gint               *minimum,
+                                               gint               *natural);
+static void     mate_hsv_size_allocate        (GtkWidget          *widget,
+                                               GtkAllocation      *allocation);
+static gboolean mate_hsv_button_press         (GtkWidget          *widget,
+                                               GdkEventButton     *event);
+static gboolean mate_hsv_button_release       (GtkWidget          *widget,
+                                               GdkEventButton     *event);
+static gboolean mate_hsv_motion               (GtkWidget          *widget,
+                                               GdkEventMotion     *event);
+static gboolean mate_hsv_draw                 (GtkWidget          *widget,
+                                               cairo_t            *cr);
+static gboolean mate_hsv_grab_broken          (GtkWidget          *widget,
+                                               GdkEventGrabBroken *event);
+static gboolean mate_hsv_focus                (GtkWidget          *widget,
+                                               GtkDirectionType    direction);
+static void     mate_hsv_move                 (MateHSV            *hsv,
+                                               GtkDirectionType    dir);
+
+static guint hsv_signals[LAST_SIGNAL];
+
+G_DEFINE_TYPE_WITH_PRIVATE (MateHSV, mate_hsv, GTK_TYPE_WIDGET)
+
+/* Class initialization function for the HSV color selector */
+static void
+mate_hsv_class_init (MateHSVClass *class)
+{
+  GObjectClass    *gobject_class;
+  GtkWidgetClass  *widget_class;
+  MateHSVClass    *hsv_class;
+  GtkBindingSet   *binding_set;
+
+  gobject_class = (GObjectClass *) class;
+  widget_class = (GtkWidgetClass *) class;
+  hsv_class = MATE_HSV_CLASS (class);
+
+  widget_class->destroy = mate_hsv_destroy;
+  widget_class->realize = mate_hsv_realize;
+  widget_class->unrealize = mate_hsv_unrealize;
+  widget_class->get_preferred_width = mate_hsv_get_preferred_width;
+  widget_class->get_preferred_height = mate_hsv_get_preferred_height;
+  widget_class->size_allocate = mate_hsv_size_allocate;
+  widget_class->button_press_event = mate_hsv_button_press;
+  widget_class->button_release_event = mate_hsv_button_release;
+  widget_class->motion_notify_event = mate_hsv_motion;
+  widget_class->draw = mate_hsv_draw;
+  widget_class->focus = mate_hsv_focus;
+  widget_class->grab_broken_event = mate_hsv_grab_broken;
+
+  gtk_widget_class_set_accessible_role (widget_class, ATK_ROLE_COLOR_CHOOSER);
+
+  hsv_class->move = mate_hsv_move;
+
+  hsv_signals[CHANGED] =
+    g_signal_new (I_("changed"),
+                  G_OBJECT_CLASS_TYPE (gobject_class),
+                  G_SIGNAL_RUN_FIRST,
+                  G_STRUCT_OFFSET (MateHSVClass, changed),
+                  NULL, NULL,
+                  NULL,
+                  G_TYPE_NONE, 0);
+
+  hsv_signals[MOVE] =
+    g_signal_new (I_("move"),
+                  G_OBJECT_CLASS_TYPE (gobject_class),
+                  G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+                  G_STRUCT_OFFSET (MateHSVClass, move),
+                  NULL, NULL,
+                  NULL,
+                  G_TYPE_NONE, 1,
+                  GTK_TYPE_DIRECTION_TYPE);
+
+  binding_set = gtk_binding_set_by_class (class);
+
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Up, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_UP);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Up, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_UP);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Down, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_DOWN);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Down, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_DOWN);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Right, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_RIGHT);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Right, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_RIGHT);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Left, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_LEFT);
+  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Left, 0,
+                                "move", 1,
+                                G_TYPE_ENUM, GTK_DIR_LEFT);
+}
+
+static void
+mate_hsv_init (MateHSV *hsv)
+{
+  MateHSVPrivate *priv;
+
+  priv = mate_hsv_get_instance_private (hsv);
+  hsv->priv = priv;
+
+  gtk_widget_set_has_window (GTK_WIDGET (hsv), FALSE);
+  gtk_widget_set_can_focus (GTK_WIDGET (hsv), TRUE);
+
+  priv->h = 0.0;
+  priv->s = 0.0;
+  priv->v = 0.0;
+
+  priv->size = DEFAULT_SIZE;
+  priv->ring_width = DEFAULT_RING_WIDTH;
+}
+
+static void
+mate_hsv_destroy (GtkWidget *widget)
+{
+  GTK_WIDGET_CLASS (mate_hsv_parent_class)->destroy (widget);
+}
+
+static void
+mate_hsv_realize (GtkWidget *widget)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+  GtkAllocation allocation;
+  GdkWindow *parent_window;
+  GdkWindowAttr attr;
+  int attr_mask;
+
+  gtk_widget_set_realized (widget, TRUE);
+
+  gtk_widget_get_allocation (widget, &allocation);
+
+  attr.window_type = GDK_WINDOW_CHILD;
+  attr.x = allocation.x;
+  attr.y = allocation.y;
+  attr.width = allocation.width;
+  attr.height = allocation.height;
+  attr.wclass = GDK_INPUT_ONLY;
+  attr.event_mask = gtk_widget_get_events (widget);
+  attr.event_mask |= (GDK_KEY_PRESS_MASK
+                      | GDK_BUTTON_PRESS_MASK
+                      | GDK_BUTTON_RELEASE_MASK
+                      | GDK_POINTER_MOTION_MASK
+                      | GDK_ENTER_NOTIFY_MASK
+                      | GDK_LEAVE_NOTIFY_MASK);
+  attr_mask = GDK_WA_X | GDK_WA_Y;
+
+  parent_window = gtk_widget_get_parent_window (widget);
+  gtk_widget_set_window (widget, parent_window);
+  g_object_ref (parent_window);
+
+  priv->window = gdk_window_new (parent_window, &attr, attr_mask);
+  gdk_window_set_user_data (priv->window, hsv);
+  gdk_window_show (priv->window);
+}
+
+static void
+mate_hsv_unrealize (GtkWidget *widget)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+
+  gdk_window_set_user_data (priv->window, NULL);
+  gdk_window_destroy (priv->window);
+  priv->window = NULL;
+
+  GTK_WIDGET_CLASS (mate_hsv_parent_class)->unrealize (widget);
+}
+
+static void
+mate_hsv_get_preferred_width (GtkWidget *widget,
+                              gint      *minimum,
+                              gint      *natural)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+  gint focus_width;
+  gint focus_pad;
+
+  gtk_widget_style_get (widget,
+                        "focus-line-width", &focus_width,
+                        "focus-padding", &focus_pad,
+                        NULL);
+
+  *minimum = priv->size + 2 * (focus_width + focus_pad);
+  *natural = priv->size + 2 * (focus_width + focus_pad);
+}
+
+static void
+mate_hsv_get_preferred_height (GtkWidget *widget,
+                               gint      *minimum,
+                               gint      *natural)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+  gint focus_width;
+  gint focus_pad;
+
+  gtk_widget_style_get (widget,
+                        "focus-line-width", &focus_width,
+                        "focus-padding", &focus_pad,
+                        NULL);
+
+  *minimum = priv->size + 2 * (focus_width + focus_pad);
+  *natural = priv->size + 2 * (focus_width + focus_pad);
+}
+
+static void
+mate_hsv_size_allocate (GtkWidget     *widget,
+                        GtkAllocation *allocation)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+
+  gtk_widget_set_allocation (widget, allocation);
+
+  if (gtk_widget_get_realized (widget))
+    gdk_window_move_resize (priv->window,
+                            allocation->x,
+                            allocation->y,
+                            allocation->width,
+                            allocation->height);
+}
+
+
+/* Utility functions */
+
+#define INTENSITY(r, g, b) ((r) * 0.30 + (g) * 0.59 + (b) * 0.11)
+
+/* Converts from HSV to RGB */
+static void
+hsv_to_rgb (gdouble *h,
+            gdouble *s,
+            gdouble *v)
+{
+  gdouble hue, saturation, value;
+  gdouble f, p, q, t;
+
+  if (*s == 0.0)
+    {
+      *h = *v;
+      *s = *v;
+      *v = *v; /* heh */
+    }
+  else
+    {
+      hue = *h * 6.0;
+      saturation = *s;
+      value = *v;
+
+      if (hue == 6.0)
+        hue = 0.0;
+
+      f = hue - (int) hue;
+      p = value * (1.0 - saturation);
+      q = value * (1.0 - saturation * f);
+      t = value * (1.0 - saturation * (1.0 - f));
+
+      switch ((int) hue)
+        {
+        case 0:
+          *h = value;
+          *s = t;
+          *v = p;
+          break;
+
+        case 1:
+          *h = q;
+          *s = value;
+          *v = p;
+          break;
+
+        case 2:
+          *h = p;
+          *s = value;
+          *v = t;
+          break;
+
+        case 3:
+          *h = p;
+          *s = q;
+          *v = value;
+          break;
+
+        case 4:
+          *h = t;
+          *s = p;
+          *v = value;
+          break;
+
+        case 5:
+          *h = value;
+          *s = p;
+          *v = q;
+          break;
+
+        default:
+          g_assert_not_reached ();
+        }
+    }
+}
+
+/* Computes the vertices of the saturation/value triangle */
+static void
+compute_triangle (MateHSV *hsv,
+                  gint    *hx,
+                  gint    *hy,
+                  gint    *sx,
+                  gint    *sy,
+                  gint    *vx,
+                  gint    *vy)
+{
+  MateHSVPrivate *priv = hsv->priv;
+  GtkWidget *widget = GTK_WIDGET (hsv);
+  gdouble center_x;
+  gdouble center_y;
+  gdouble inner, outer;
+  gdouble angle;
+
+  center_x = gtk_widget_get_allocated_width (widget) / 2.0;
+  center_y = gtk_widget_get_allocated_height (widget) / 2.0;
+  outer = priv->size / 2.0;
+  inner = outer - priv->ring_width;
+  angle = priv->h * 2.0 * G_PI;
+
+  *hx = floor (center_x + cos (angle) * inner + 0.5);
+  *hy = floor (center_y - sin (angle) * inner + 0.5);
+  *sx = floor (center_x + cos (angle + 2.0 * G_PI / 3.0) * inner + 0.5);
+  *sy = floor (center_y - sin (angle + 2.0 * G_PI / 3.0) * inner + 0.5);
+  *vx = floor (center_x + cos (angle + 4.0 * G_PI / 3.0) * inner + 0.5);
+  *vy = floor (center_y - sin (angle + 4.0 * G_PI / 3.0) * inner + 0.5);
+}
+
+/* Computes whether a point is inside the hue ring */
+static gboolean
+is_in_ring (MateHSV *hsv,
+            gdouble  x,
+            gdouble  y)
+{
+  MateHSVPrivate *priv = hsv->priv;
+  GtkWidget *widget = GTK_WIDGET (hsv);
+  gdouble dx, dy, dist;
+  gdouble center_x;
+  gdouble center_y;
+  gdouble inner, outer;
+
+  center_x = gtk_widget_get_allocated_width (widget) / 2.0;
+  center_y = gtk_widget_get_allocated_height (widget) / 2.0;
+  outer = priv->size / 2.0;
+  inner = outer - priv->ring_width;
+
+  dx = x - center_x;
+  dy = center_y - y;
+  dist = dx * dx + dy * dy;
+
+  return (dist >= inner * inner && dist <= outer * outer);
+}
+
+/* Computes a saturation/value pair based on the mouse coordinates */
+static void
+compute_sv (MateHSV  *hsv,
+            gdouble   x,
+            gdouble   y,
+            gdouble  *s,
+            gdouble  *v)
+{
+  GtkWidget *widget = GTK_WIDGET (hsv);
+  int ihx, ihy, isx, isy, ivx, ivy;
+  double hx, hy, sx, sy, vx, vy;
+  double center_x;
+  double center_y;
+
+  compute_triangle (hsv, &ihx, &ihy, &isx, &isy, &ivx, &ivy);
+  center_x = gtk_widget_get_allocated_width (widget) / 2.0;
+  center_y = gtk_widget_get_allocated_height (widget) / 2.0;
+  hx = ihx - center_x;
+  hy = center_y - ihy;
+  sx = isx - center_x;
+  sy = center_y - isy;
+  vx = ivx - center_x;
+  vy = center_y - ivy;
+  x -= center_x;
+  y = center_y - y;
+  
+  if (vx * (x - sx) + vy * (y - sy) < 0.0)
+    {
+      *s = 1.0;
+      *v = (((x - sx) * (hx - sx) + (y - sy) * (hy-sy))
+            / ((hx - sx) * (hx - sx) + (hy - sy) * (hy - sy)));
+      
+      if (*v < 0.0)
+        *v = 0.0;
+      else if (*v > 1.0)
+        *v = 1.0;
+    }
+  else if (hx * (x - sx) + hy * (y - sy) < 0.0)
+    {
+      *s = 0.0;
+      *v = (((x - sx) * (vx - sx) + (y - sy) * (vy - sy))
+            / ((vx - sx) * (vx - sx) + (vy - sy) * (vy - sy)));
+      
+      if (*v < 0.0)
+        *v = 0.0;
+      else if (*v > 1.0)
+        *v = 1.0;
+    }
+  else if (sx * (x - hx) + sy * (y - hy) < 0.0)
+    {
+      *v = 1.0;
+      *s = (((x - vx) * (hx - vx) + (y - vy) * (hy - vy)) /
+            ((hx - vx) * (hx - vx) + (hy - vy) * (hy - vy)));
+      
+      if (*s < 0.0)
+        *s = 0.0;
+      else if (*s > 1.0)
+        *s = 1.0;
+    }
+  else
+    {
+      *v = (((x - sx) * (hy - vy) - (y - sy) * (hx - vx))
+            / ((vx - sx) * (hy - vy) - (vy - sy) * (hx - vx)));
+      
+      if (*v<= 0.0)
+        {
+          *v = 0.0;
+          *s = 0.0;
+        }
+      else
+        {
+          if (*v > 1.0)
+            *v = 1.0;
+
+          if (fabs (hy - vy) < fabs (hx - vx))
+            *s = (x - sx - *v * (vx - sx)) / (*v * (hx - vx));
+          else
+            *s = (y - sy - *v * (vy - sy)) / (*v * (hy - vy));
+
+          if (*s < 0.0)
+            *s = 0.0;
+          else if (*s > 1.0)
+            *s = 1.0;
+        }
+    }
+}
+
+/* Computes whether a point is inside the saturation/value triangle */
+static gboolean
+is_in_triangle (MateHSV *hsv,
+                gdouble  x,
+                gdouble  y)
+{
+  int hx, hy, sx, sy, vx, vy;
+  double det, s, v;
+  
+  compute_triangle (hsv, &hx, &hy, &sx, &sy, &vx, &vy);
+  
+  det = (vx - sx) * (hy - sy) - (vy - sy) * (hx - sx);
+  
+  s = ((x - sx) * (hy - sy) - (y - sy) * (hx - sx)) / det;
+  v = ((vx - sx) * (y - sy) - (vy - sy) * (x - sx)) / det;
+  
+  return (s >= 0.0 && v >= 0.0 && s + v <= 1.0);
+}
+
+/* Computes a value based on the mouse coordinates */
+static double
+compute_v (MateHSV *hsv,
+           gdouble  x,
+           gdouble  y)
+{
+  GtkWidget *widget = GTK_WIDGET (hsv);
+  double center_x;
+  double center_y;
+  double dx, dy;
+  double angle;
+
+  center_x = gtk_widget_get_allocated_width (widget) / 2.0;
+  center_y = gtk_widget_get_allocated_height (widget) / 2.0;
+  dx = x - center_x;
+  dy = center_y - y;
+
+  angle = atan2 (dy, dx);
+  if (angle < 0.0)
+    angle += 2.0 * G_PI;
+
+  return angle / (2.0 * G_PI);
+}
+
+/* Event handlers */
+
+static void
+set_cross_grab (MateHSV   *hsv,
+                GdkDevice *device,
+                guint32    time)
+{
+  MateHSVPrivate *priv = hsv->priv;
+  GdkCursor *cursor;
+
+  cursor = gdk_cursor_new_for_display (gtk_widget_get_display (GTK_WIDGET (hsv)),
+                                       GDK_CROSSHAIR);
+  gdk_device_grab (device,
+                   priv->window,
+                   GDK_OWNERSHIP_NONE,
+                   FALSE,
+                   GDK_POINTER_MOTION_MASK
+                    | GDK_POINTER_MOTION_HINT_MASK
+                    | GDK_BUTTON_RELEASE_MASK,
+                   cursor,
+                   time);
+  g_object_unref (cursor);
+}
+
+static gboolean
+mate_hsv_grab_broken (GtkWidget          *widget,
+                      GdkEventGrabBroken *event)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+
+  priv->mode = DRAG_NONE;
+
+  return TRUE;
+}
+
+static gint
+mate_hsv_button_press (GtkWidget      *widget,
+                       GdkEventButton *event)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+  double x, y;
+
+  if (priv->mode != DRAG_NONE || event->button != GDK_BUTTON_PRIMARY)
+    return FALSE;
+
+  x = event->x;
+  y = event->y;
+
+  if (is_in_ring (hsv, x, y))
+    {
+      priv->mode = DRAG_H;
+      set_cross_grab (hsv, gdk_event_get_device ((GdkEvent *) event), event->time);
+
+      mate_hsv_set_color (hsv,
+                         compute_v (hsv, x, y),
+                         priv->s,
+                         priv->v);
+
+      gtk_widget_grab_focus (widget);
+      priv->focus_on_ring = TRUE;
+
+      return TRUE;
+    }
+
+  if (is_in_triangle (hsv, x, y))
+    {
+      gdouble s, v;
+
+      priv->mode = DRAG_SV;
+      set_cross_grab (hsv, gdk_event_get_device ((GdkEvent *) event), event->time);
+
+      compute_sv (hsv, x, y, &s, &v);
+      mate_hsv_set_color (hsv, priv->h, s, v);
+
+      gtk_widget_grab_focus (widget);
+      priv->focus_on_ring = FALSE;
+
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
+static gint
+mate_hsv_button_release (GtkWidget      *widget,
+                         GdkEventButton *event)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+  DragMode mode;
+  gdouble x, y;
+
+  if (priv->mode == DRAG_NONE || event->button != GDK_BUTTON_PRIMARY)
+    return FALSE;
+
+  /* Set the drag mode to DRAG_NONE so that signal handlers for "catched"
+   * can see that this is the final color state.
+   */
+  mode = priv->mode;
+  priv->mode = DRAG_NONE;
+
+  x = event->x;
+  y = event->y;
+
+  if (mode == DRAG_H)
+    {
+      mate_hsv_set_color (hsv, compute_v (hsv, x, y), priv->s, priv->v);
+    }
+  else if (mode == DRAG_SV)
+    {
+      gdouble s, v;
+
+      compute_sv (hsv, x, y, &s, &v);
+      mate_hsv_set_color (hsv, priv->h, s, v);
+    }
+  else
+    {
+      g_assert_not_reached ();
+    }
+
+  gdk_device_ungrab (gdk_event_get_device ((GdkEvent *) event), event->time);
+
+  return TRUE;
+}
+
+static gint
+mate_hsv_motion (GtkWidget      *widget,
+                 GdkEventMotion *event)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+  gdouble x, y;
+
+  if (priv->mode == DRAG_NONE)
+    return FALSE;
+
+  gdk_event_request_motions (event);
+  x = event->x;
+  y = event->y;
+
+  if (priv->mode == DRAG_H)
+    {
+      mate_hsv_set_color (hsv, compute_v (hsv, x, y), priv->s, priv->v);
+      return TRUE;
+    }
+  else if (priv->mode == DRAG_SV)
+    {
+      gdouble s, v;
+
+      compute_sv (hsv, x, y, &s, &v);
+      mate_hsv_set_color (hsv, priv->h, s, v);
+      return TRUE;
+    }
+
+  g_assert_not_reached ();
+
+  return FALSE;
+}
+
+
+/* Redrawing */
+
+/* Paints the hue ring */
+static void
+paint_ring (MateHSV *hsv,
+            cairo_t *cr)
+{
+  MateHSVPrivate *priv = hsv->priv;
+  GtkWidget *widget = GTK_WIDGET (hsv);
+  int xx, yy, width, height;
+  gdouble dx, dy, dist;
+  gdouble center_x;
+  gdouble center_y;
+  gdouble inner, outer;
+  guint32 *buf, *p;
+  gdouble angle;
+  gdouble hue;
+  gdouble r, g, b;
+  cairo_surface_t *source;
+  cairo_t *source_cr;
+  gint stride;
+
+  width = gtk_widget_get_allocated_width (widget);
+  height = gtk_widget_get_allocated_height (widget);
+
+  center_x = width / 2.0;
+  center_y = height / 2.0;
+
+  outer = priv->size / 2.0;
+  inner = outer - priv->ring_width;
+
+  /* Create an image initialized with the ring colors */
+
+  stride = cairo_format_stride_for_width (CAIRO_FORMAT_RGB24, width);
+  buf = g_new (guint32, height * stride / 4);
+
+  for (yy = 0; yy < height; yy++)
+    {
+      p = buf + yy * width;
+
+      dy = -(yy - center_y);
+
+      for (xx = 0; xx < width; xx++)
+        {
+          dx = xx - center_x;
+
+          dist = dx * dx + dy * dy;
+          if (dist < ((inner-1) * (inner-1)) || dist > ((outer+1) * (outer+1)))
+            {
+              *p++ = 0;
+              continue;
+            }
+
+          angle = atan2 (dy, dx);
+          if (angle < 0.0)
+            angle += 2.0 * G_PI;
+
+          hue = angle / (2.0 * G_PI);
+
+          r = hue;
+          g = 1.0;
+          b = 1.0;
+          hsv_to_rgb (&r, &g, &b);
+
+          *p++ = (((int)floor (r * 255 + 0.5) << 16) |
+                  ((int)floor (g * 255 + 0.5) << 8) |
+                  (int)floor (b * 255 + 0.5));
+        }
+    }
+
+  source = cairo_image_surface_create_for_data ((unsigned char *)buf,
+                                                CAIRO_FORMAT_RGB24,
+                                                width, height, stride);
+
+  /* Now draw the value marker onto the source image, so that it
+   * will get properly clipped at the edges of the ring
+   */
+  source_cr = cairo_create (source);
+  
+  r = priv->h;
+  g = 1.0;
+  b = 1.0;
+  hsv_to_rgb (&r, &g, &b);
+  
+  if (INTENSITY (r, g, b) > 0.5)
+    cairo_set_source_rgb (source_cr, 0., 0., 0.);
+  else
+    cairo_set_source_rgb (source_cr, 1., 1., 1.);
+
+  cairo_move_to (source_cr, center_x, center_y);
+  cairo_line_to (source_cr,
+                 center_x + cos (priv->h * 2.0 * G_PI) * priv->size / 2,
+                 center_y - sin (priv->h * 2.0 * G_PI) * priv->size / 2);
+  cairo_stroke (source_cr);
+  cairo_destroy (source_cr);
+
+  /* Draw the ring using the source image */
+
+  cairo_save (cr);
+    
+  cairo_set_source_surface (cr, source, 0, 0);
+  cairo_surface_destroy (source);
+
+  cairo_set_line_width (cr, priv->ring_width);
+  cairo_new_path (cr);
+  cairo_arc (cr,
+             center_x, center_y,
+             priv->size / 2. - priv->ring_width / 2.,
+             0, 2 * G_PI);
+  cairo_stroke (cr);
+  
+  cairo_restore (cr);
+  
+  g_free (buf);
+}
+
+/* Converts an HSV triplet to an integer RGB triplet */
+static void
+get_color (gdouble h,
+           gdouble s,
+           gdouble v,
+           gint   *r,
+           gint   *g,
+           gint   *b)
+{
+  hsv_to_rgb (&h, &s, &v);
+  
+  *r = floor (h * 255 + 0.5);
+  *g = floor (s * 255 + 0.5);
+  *b = floor (v * 255 + 0.5);
+}
+
+#define SWAP(a, b, t) ((t) = (a), (a) = (b), (b) = (t))
+
+#define LERP(a, b, v1, v2, i) (((v2) - (v1) != 0)                                       \
+                               ? ((a) + ((b) - (a)) * ((i) - (v1)) / ((v2) - (v1)))     \
+                               : (a))
+
+/* Number of pixels we extend out from the edges when creating
+ * color source to avoid artifacts
+ */
+#define PAD 3
+
+/* Paints the HSV triangle */
+static void
+paint_triangle (MateHSV  *hsv,
+                cairo_t  *cr,
+                gboolean  draw_focus)
+{
+  MateHSVPrivate *priv = hsv->priv;
+  GtkWidget *widget = GTK_WIDGET (hsv);
+  gint hx, hy, sx, sy, vx, vy; /* HSV vertices */
+  gint x1, y1, r1, g1, b1; /* First vertex in scanline order */
+  gint x2, y2, r2, g2, b2; /* Second vertex */
+  gint x3, y3, r3, g3, b3; /* Third vertex */
+  gint t;
+  guint32 *buf, *p, c;
+  gint xl, xr, rl, rr, gl, gr, bl, br; /* Scanline data */
+  gint xx, yy;
+  gint x_interp, y_interp;
+  gint x_start, x_end;
+  cairo_surface_t *source;
+  gdouble r, g, b;
+  gint stride;
+  int width, height;
+  GtkStyleContext *context;
+
+  priv = hsv->priv;
+  width = gtk_widget_get_allocated_width (widget); 
+  height = gtk_widget_get_allocated_height (widget); 
+  /* Compute triangle's vertices */
+  
+  compute_triangle (hsv, &hx, &hy, &sx, &sy, &vx, &vy);
+  
+  x1 = hx;
+  y1 = hy;
+  get_color (priv->h, 1.0, 1.0, &r1, &g1, &b1);
+
+  x2 = sx;
+  y2 = sy;
+  get_color (priv->h, 1.0, 0.0, &r2, &g2, &b2);
+
+  x3 = vx;
+  y3 = vy;
+  get_color (priv->h, 0.0, 1.0, &r3, &g3, &b3);
+
+  if (y2 > y3)
+    {
+      SWAP (x2, x3, t);
+      SWAP (y2, y3, t);
+      SWAP (r2, r3, t);
+      SWAP (g2, g3, t);
+      SWAP (b2, b3, t);
+    }
+
+  if (y1 > y3)
+    {
+      SWAP (x1, x3, t);
+      SWAP (y1, y3, t);
+      SWAP (r1, r3, t);
+      SWAP (g1, g3, t);
+      SWAP (b1, b3, t);
+    }
+
+  if (y1 > y2)
+    {
+      SWAP (x1, x2, t);
+      SWAP (y1, y2, t);
+      SWAP (r1, r2, t);
+      SWAP (g1, g2, t);
+      SWAP (b1, b2, t);
+    }
+
+  /* Shade the triangle */
+
+  stride = cairo_format_stride_for_width (CAIRO_FORMAT_RGB24, width);
+  buf = g_new (guint32, height * stride / 4);
+
+  for (yy = 0; yy < height; yy++)
+    {
+      p = buf + yy * width;
+
+      if (yy >= y1 - PAD && yy < y3 + PAD) {
+        y_interp = CLAMP (yy, y1, y3);
+
+        if (y_interp < y2)
+          {
+            xl = LERP (x1, x2, y1, y2, y_interp);
+
+            rl = LERP (r1, r2, y1, y2, y_interp);
+            gl = LERP (g1, g2, y1, y2, y_interp);
+            bl = LERP (b1, b2, y1, y2, y_interp);
+          }
+        else
+          {
+            xl = LERP (x2, x3, y2, y3, y_interp);
+
+            rl = LERP (r2, r3, y2, y3, y_interp);
+            gl = LERP (g2, g3, y2, y3, y_interp);
+            bl = LERP (b2, b3, y2, y3, y_interp);
+          }
+
+        xr = LERP (x1, x3, y1, y3, y_interp);
+
+        rr = LERP (r1, r3, y1, y3, y_interp);
+        gr = LERP (g1, g3, y1, y3, y_interp);
+        br = LERP (b1, b3, y1, y3, y_interp);
+
+        if (xl > xr)
+          {
+            SWAP (xl, xr, t);
+            SWAP (rl, rr, t);
+            SWAP (gl, gr, t);
+            SWAP (bl, br, t);
+          }
+
+        x_start = MAX (xl - PAD, 0);
+        x_end = MIN (xr + PAD, width);
+        x_start = MIN (x_start, x_end);
+
+        c = (rl << 16) | (gl << 8) | bl;
+
+        for (xx = 0; xx < x_start; xx++)
+          *p++ = c;
+
+        for (; xx < x_end; xx++)
+          {
+            x_interp = CLAMP (xx, xl, xr);
+
+            *p++ = ((LERP (rl, rr, xl, xr, x_interp) << 16) |
+                    (LERP (gl, gr, xl, xr, x_interp) << 8) |
+                    LERP (bl, br, xl, xr, x_interp));
+          }
+
+        c = (rr << 16) | (gr << 8) | br;
+
+        for (; xx < width; xx++)
+          *p++ = c;
+      }
+    }
+
+  source = cairo_image_surface_create_for_data ((unsigned char *)buf,
+                                                CAIRO_FORMAT_RGB24,
+                                                width, height, stride);
+  
+  /* Draw a triangle with the image as a source */
+
+  cairo_set_source_surface (cr, source, 0, 0);
+  cairo_surface_destroy (source);
+  
+  cairo_move_to (cr, x1, y1);
+  cairo_line_to (cr, x2, y2);
+  cairo_line_to (cr, x3, y3);
+  cairo_close_path (cr);
+  cairo_fill (cr);
+  
+  g_free (buf);
+  
+  /* Draw value marker */
+  
+  xx = floor (sx + (vx - sx) * priv->v + (hx - vx) * priv->s * priv->v + 0.5);
+  yy = floor (sy + (vy - sy) * priv->v + (hy - vy) * priv->s * priv->v + 0.5);
+  
+  r = priv->h;
+  g = priv->s;
+  b = priv->v;
+  hsv_to_rgb (&r, &g, &b);
+
+  context = gtk_widget_get_style_context (widget);
+
+  gtk_style_context_save (context);
+
+  if (INTENSITY (r, g, b) > 0.5)
+    {
+      gtk_style_context_add_class (context, "light-area-focus");
+      cairo_set_source_rgb (cr, 0., 0., 0.);
+    }
+  else
+    {
+      gtk_style_context_add_class (context, "dark-area-focus");
+      cairo_set_source_rgb (cr, 1., 1., 1.);
+    }
+
+#define RADIUS 4
+#define FOCUS_RADIUS 6
+
+  cairo_new_path (cr);
+  cairo_arc (cr, xx, yy, RADIUS, 0, 2 * G_PI);
+  cairo_stroke (cr);
+  
+  /* Draw focus outline */
+
+  if (draw_focus && !priv->focus_on_ring)
+    {
+      gint focus_width;
+      gint focus_pad;
+
+      gtk_widget_style_get (widget,
+                            "focus-line-width", &focus_width,
+                            "focus-padding", &focus_pad,
+                            NULL);
+
+      gtk_render_focus (context, cr,
+                        xx - FOCUS_RADIUS - focus_width - focus_pad,
+                        yy - FOCUS_RADIUS - focus_width - focus_pad,
+                        2 * (FOCUS_RADIUS + focus_width + focus_pad),
+                        2 * (FOCUS_RADIUS + focus_width + focus_pad));
+    }
+
+  gtk_style_context_restore (context);
+}
+
+/* Paints the contents of the HSV color selector */
+static gboolean
+mate_hsv_draw (GtkWidget *widget,
+               cairo_t   *cr)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+  gboolean draw_focus;
+
+  draw_focus = gtk_widget_has_visible_focus (widget);
+
+  paint_ring (hsv, cr);
+  paint_triangle (hsv, cr, draw_focus);
+
+
+  if (draw_focus && priv->focus_on_ring)
+    {
+      GtkStyleContext *context;
+
+      context = gtk_widget_get_style_context (widget);
+
+      gtk_render_focus (context, cr, 0, 0,
+                        gtk_widget_get_allocated_width (widget),
+                        gtk_widget_get_allocated_height (widget));
+    }
+
+  return FALSE;
+}
+
+static gboolean
+mate_hsv_focus (GtkWidget       *widget,
+                GtkDirectionType dir)
+{
+  MateHSV *hsv = MATE_HSV (widget);
+  MateHSVPrivate *priv = hsv->priv;
+
+  if (!gtk_widget_has_focus (widget))
+    {
+      if (dir == GTK_DIR_TAB_BACKWARD)
+        priv->focus_on_ring = FALSE;
+      else
+        priv->focus_on_ring = TRUE;
+
+      gtk_widget_grab_focus (GTK_WIDGET (hsv));
+      return TRUE;
+    }
+  
+  switch (dir)
+    {
+    case GTK_DIR_UP:
+      if (priv->focus_on_ring)
+        return FALSE;
+      else
+        priv->focus_on_ring = TRUE;
+      break;
+
+    case GTK_DIR_DOWN:
+      if (priv->focus_on_ring)
+        priv->focus_on_ring = FALSE;
+      else
+        return FALSE;
+      break;
+
+    case GTK_DIR_LEFT:
+    case GTK_DIR_TAB_BACKWARD:
+      if (priv->focus_on_ring)
+        return FALSE;
+      else
+        priv->focus_on_ring = TRUE;
+      break;
+
+    case GTK_DIR_RIGHT:
+    case GTK_DIR_TAB_FORWARD:
+      if (priv->focus_on_ring)
+        priv->focus_on_ring = FALSE;
+      else
+        return FALSE;
+      break;
+    }
+
+  gtk_widget_queue_draw (GTK_WIDGET (hsv));
+
+  return TRUE;
+}
+
+/**
+ * mate_hsv_new:
+ *
+ * Creates a new HSV color selector.
+ *
+ * Returns: A newly-created HSV color selector.
+ */
+GtkWidget*
+mate_hsv_new (void)
+{
+  return g_object_new (MATE_TYPE_HSV, NULL);
+}
+
+/**
+ * mate_hsv_set_color:
+ * @hsv: An HSV color selector
+ * @h: Hue
+ * @s: Saturation
+ * @v: Value
+ *
+ * Sets the current color in an HSV color selector.
+ * Color component values must be in the [0.0, 1.0] range.
+ */
+void
+mate_hsv_set_color (MateHSV *hsv,
+                    gdouble  h,
+                    gdouble  s,
+                    gdouble  v)
+{
+  MateHSVPrivate *priv;
+
+  g_return_if_fail (MATE_IS_HSV (hsv));
+  g_return_if_fail (h >= 0.0 && h <= 1.0);
+  g_return_if_fail (s >= 0.0 && s <= 1.0);
+  g_return_if_fail (v >= 0.0 && v <= 1.0);
+
+  priv = hsv->priv;
+
+  priv->h = h;
+  priv->s = s;
+  priv->v = v;
+  
+  g_signal_emit (hsv, hsv_signals[CHANGED], 0);
+  
+  gtk_widget_queue_draw (GTK_WIDGET (hsv));
+}
+
+/**
+ * mate_hsv_get_color:
+ * @hsv: An HSV color selector
+ * @h: (out): Return value for the hue
+ * @s: (out): Return value for the saturation
+ * @v: (out): Return value for the value
+ *
+ * Queries the current color in an HSV color selector.
+ * Returned values will be in the [0.0, 1.0] range.
+ */
+void
+mate_hsv_get_color (MateHSV *hsv,
+                    double  *h,
+                    double  *s,
+                    double  *v)
+{
+  MateHSVPrivate *priv;
+
+  g_return_if_fail (MATE_IS_HSV (hsv));
+
+  priv = hsv->priv;
+
+  if (h)
+    *h = priv->h;
+
+  if (s)
+    *s = priv->s;
+
+  if (v)
+    *v = priv->v;
+}
+
+/**
+ * mate_hsv_set_metrics:
+ * @hsv: An HSV color selector
+ * @size: Diameter for the hue ring
+ * @ring_width: Width of the hue ring
+ *
+ * Sets the size and ring width of an HSV color selector.
+ */
+void
+mate_hsv_set_metrics (MateHSV *hsv,
+                      gint     size,
+                      gint     ring_width)
+{
+  MateHSVPrivate *priv;
+  int same_size;
+
+  g_return_if_fail (MATE_IS_HSV (hsv));
+  g_return_if_fail (size > 0);
+  g_return_if_fail (ring_width > 0);
+  g_return_if_fail (2 * ring_width + 1 <= size);
+
+  priv = hsv->priv;
+
+  same_size = (priv->size == size);
+
+  priv->size = size;
+  priv->ring_width = ring_width;
+  
+  if (same_size)
+    gtk_widget_queue_draw (GTK_WIDGET (hsv));
+  else
+    gtk_widget_queue_resize (GTK_WIDGET (hsv));
+}
+
+/**
+ * mate_hsv_get_metrics:
+ * @hsv: An HSV color selector
+ * @size: (out): Return value for the diameter of the hue ring
+ * @ring_width: (out): Return value for the width of the hue ring
+ *
+ * Queries the size and ring width of an HSV color selector.
+ */
+void
+mate_hsv_get_metrics (MateHSV *hsv,
+                      gint    *size,
+                      gint    *ring_width)
+{
+  MateHSVPrivate *priv;
+
+  g_return_if_fail (MATE_IS_HSV (hsv));
+
+  priv = hsv->priv;
+
+  if (size)
+    *size = priv->size;
+  
+  if (ring_width)
+    *ring_width = priv->ring_width;
+}
+
+/**
+ * mate_hsv_is_adjusting:
+ * @hsv: A #MateHSV 
+ *
+ * An HSV color selector can be said to be adjusting if multiple rapid
+ * changes are being made to its value, for example, when the user is 
+ * adjusting the value with the mouse. This function queries whether 
+ * the HSV color selector is being adjusted or not.
+ *
+ * Returns: %TRUE if clients can ignore changes to the color value,
+ *     since they may be transitory, or %FALSE if they should consider
+ *     the color value status to be final.
+ */
+gboolean
+mate_hsv_is_adjusting (MateHSV *hsv)
+{
+  MateHSVPrivate *priv;
+
+  g_return_val_if_fail (MATE_IS_HSV (hsv), FALSE);
+
+  priv = hsv->priv;
+
+  return priv->mode != DRAG_NONE;
+}
+
+static void
+mate_hsv_move (MateHSV         *hsv,
+               GtkDirectionType dir)
+{
+  MateHSVPrivate *priv = hsv->priv;
+  gdouble hue, sat, val;
+  gint hx, hy, sx, sy, vx, vy; /* HSV vertices */
+  gint x, y; /* position in triangle */
+
+  hue = priv->h;
+  sat = priv->s;
+  val = priv->v;
+
+  compute_triangle (hsv, &hx, &hy, &sx, &sy, &vx, &vy);
+
+  x = floor (sx + (vx - sx) * priv->v + (hx - vx) * priv->s * priv->v + 0.5);
+  y = floor (sy + (vy - sy) * priv->v + (hy - vy) * priv->s * priv->v + 0.5);
+
+#define HUE_DELTA 0.002
+  switch (dir)
+    {
+    case GTK_DIR_UP:
+      if (priv->focus_on_ring)
+        hue += HUE_DELTA;
+      else
+        {
+          y -= 1;
+          compute_sv (hsv, x, y, &sat, &val);
+        }
+      break;
+
+    case GTK_DIR_DOWN:
+      if (priv->focus_on_ring)
+        hue -= HUE_DELTA;
+      else
+        {
+          y += 1;
+          compute_sv (hsv, x, y, &sat, &val);
+        }
+      break;
+
+    case GTK_DIR_LEFT:
+      if (priv->focus_on_ring)
+        hue += HUE_DELTA;
+      else
+        {
+          x -= 1;
+          compute_sv (hsv, x, y, &sat, &val);
+        }
+      break;
+
+    case GTK_DIR_RIGHT:
+      if (priv->focus_on_ring)
+        hue -= HUE_DELTA
+          ;
+      else
+        {
+          x += 1;
+          compute_sv (hsv, x, y, &sat, &val);
+        }
+      break;
+
+    default:
+      /* we don't care about the tab directions */
+      break;
+    }
+
+  /* Wrap */
+  if (hue < 0.0)
+    hue = 1.0;
+  else if (hue > 1.0)
+    hue = 0.0;
+  
+  mate_hsv_set_color (hsv, hue, sat, val);
+}
+