Initial revision

1 files changed, 860 insertions, 0 deletions

diff --git a/gtk/gtkcurve.c b/gtk/gtkcurve.c
new file mode 100644
index 0000000000..d2b6e08c84
--- /dev/null
+++ b/gtk/gtkcurve.c
@@ -0,0 +1,860 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 1997 David Mosberger
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <string.h>
+#include <math.h>
+
+#include "gtkcurve.h"
+#include "gtkdrawingarea.h"
+#include "gtkmain.h"
+#include "gtkradiobutton.h"
+#include "gtksignal.h"
+#include "gtktable.h"
+
+#define BOUNDS(a,x,y)	(((a) < (x)) ? (x) : (((a) > (y)) ? (y) : (a)))
+#define RADIUS		3	/* radius of the control points */
+#define MIN_DISTANCE	8	/* min distance between control points */
+
+#define GRAPH_MASK	(GDK_EXPOSURE_MASK |		\
+			 GDK_POINTER_MOTION_MASK |	\
+			 GDK_POINTER_MOTION_HINT_MASK |	\
+			 GDK_ENTER_NOTIFY_MASK |	\
+			 GDK_BUTTON_PRESS_MASK |	\
+			 GDK_BUTTON_RELEASE_MASK |	\
+			 GDK_BUTTON1_MOTION_MASK)
+
+static GtkDrawingAreaClass *parent_class = NULL;
+static gint curve_type_changed_signal = 0;
+
+
+/* forward declarations: */
+static void gtk_curve_class_init (GtkCurveClass *class);
+static void gtk_curve_init (GtkCurve *curve);
+static void gtk_curve_destroy (GtkObject *object);
+
+
+guint
+gtk_curve_get_type (void)
+{
+  static guint curve_type = 0;
+
+  if (!curve_type)
+    {
+      GtkTypeInfo curve_info =
+      {
+	"GtkCurve",
+	sizeof (GtkCurve),
+	sizeof (GtkCurveClass),
+	(GtkClassInitFunc) gtk_curve_class_init,
+	(GtkObjectInitFunc) gtk_curve_init,
+	(GtkArgFunc) NULL,
+      };
+
+      curve_type = gtk_type_unique (gtk_drawing_area_get_type (), &curve_info);
+    }
+  return curve_type;
+}
+
+static void
+gtk_curve_class_init (GtkCurveClass *class)
+{
+  GtkObjectClass *object_class;
+
+  parent_class = gtk_type_class (gtk_drawing_area_get_type ());
+
+  object_class = (GtkObjectClass *) class;
+
+  curve_type_changed_signal =
+    gtk_signal_new ("curve_type_changed", GTK_RUN_FIRST, object_class->type,
+		    GTK_SIGNAL_OFFSET (GtkCurveClass, curve_type_changed),
+		    gtk_signal_default_marshaller, GTK_TYPE_NONE, 0);
+  gtk_object_class_add_signals (object_class, &curve_type_changed_signal, 1);
+
+  object_class->destroy = gtk_curve_destroy;
+}
+
+static void
+gtk_curve_init (GtkCurve *curve)
+{
+  curve->cursor_type = GDK_TOP_LEFT_ARROW;
+  curve->pixmap = NULL;
+  curve->curve_type = GTK_CURVE_TYPE_SPLINE;
+  curve->height = 0;
+  curve->grab_point = -1;
+
+  curve->num_points = 0;
+  curve->point = 0;
+
+  curve->num_ctlpoints = 0;
+  curve->ctlpoint = NULL;
+}
+
+static int
+project (gfloat value, gfloat min, gfloat max, int norm)
+{
+  return (norm - 1) * ((value - min) / (max - min)) + 0.5;
+}
+
+static gfloat
+unproject (gint value, gfloat min, gfloat max, int norm)
+{
+  return value / (gfloat) (norm - 1) * (max - min) + min;
+}
+
+/* Solve the tridiagonal equation system that determines the second
+   derivatives for the interpolation points.  (Based on Numerical
+   Recipies 2nd Edition.) */
+static void
+spline_solve (int n, gfloat x[], gfloat y[], gfloat y2[])
+{
+  gfloat p, sig, *u;
+  gint i, k;
+
+  u = g_malloc ((n - 1) * sizeof (u[0]));
+
+  y2[0] = u[0] = 0.0;	/* set lower boundary condition to "natural" */
+
+  for (i = 1; i < n - 1; ++i)
+    {
+      sig = (x[i] - x[i - 1]) / (x[i + 1] - x[i - 1]);
+      p = sig * y2[i - 1] + 2.0;
+      y2[i] = (sig - 1.0) / p;
+      u[i] = ((y[i + 1] - y[i])
+	      / (x[i + 1] - x[i]) - (y[i] - y[i - 1]) / (x[i] - x[i - 1]));
+      u[i] = (6.0 * u[i] / (x[i + 1] - x[i - 1]) - sig * u[i - 1]) / p;
+    }
+
+  y2[n - 1] = 0.0;
+  for (k = n - 2; k >= 0; --k)
+    y2[k] = y2[k] * y2[k + 1] + u[k];
+
+  g_free (u);
+}
+
+static gfloat
+spline_eval (int n, gfloat x[], gfloat y[], gfloat y2[], gfloat val)
+{
+  gint k_lo, k_hi, k;
+  gfloat h, b, a;
+
+  /* do a binary search for the right interval: */
+  k_lo = 0; k_hi = n - 1;
+  while (k_hi - k_lo > 1)
+    {
+      k = (k_hi + k_lo) / 2;
+      if (x[k] > val)
+	k_hi = k;
+      else
+	k_lo = k;
+    }
+
+  h = x[k_hi] - x[k_lo];
+  g_assert (h > 0.0);
+
+  a = (x[k_hi] - val) / h;
+  b = (val - x[k_lo]) / h;
+  return a*y[k_lo] + b*y[k_hi] +
+    ((a*a*a - a)*y2[k_lo] + (b*b*b - b)*y2[k_hi]) * (h*h)/6.0;
+}
+
+static void
+gtk_curve_interpolate (GtkCurve *c, gint width, gint height)
+{
+  gfloat *vector;
+  int i;
+
+  vector = g_malloc (width * sizeof (vector[0]));
+
+  gtk_curve_get_vector (c, width, vector);
+
+  c->height = height;
+  if (c->num_points != width)
+    {
+      c->num_points = width;
+      if (c->point)
+	g_free (c->point);
+      c->point = g_malloc (c->num_points * sizeof (c->point[0]));
+    }
+
+  for (i = 0; i < width; ++i)
+    {
+      c->point[i].x = RADIUS + i;
+      c->point[i].y = RADIUS + height
+	- project (vector[i], c->min_y, c->max_y, height);
+    }
+}
+
+static void
+gtk_curve_draw (GtkCurve *c, gint width, gint height)
+{
+  GtkStateType state;
+  GtkStyle *style;
+  gint i;
+
+  if (!c->pixmap)
+    return;
+
+  if (c->height != height || c->num_points != width)
+    gtk_curve_interpolate (c, width, height);
+
+  state = GTK_STATE_NORMAL;
+  if (!GTK_WIDGET_IS_SENSITIVE (GTK_WIDGET (c)))
+    state = GTK_STATE_INSENSITIVE;
+
+  style = GTK_WIDGET (c)->style;
+
+  /* clear the pixmap: */
+  gdk_draw_rectangle (c->pixmap, style->bg_gc[state], TRUE,
+		      0, 0, width + RADIUS * 2, height + RADIUS * 2);
+
+  /* draw the grid lines: (XXX make more meaningful) */
+  for (i = 0; i < 5; i++)
+    {
+      gdk_draw_line (c->pixmap, style->dark_gc[state],
+		     RADIUS, i * (height / 4.0) + RADIUS,
+		     width + RADIUS, i * (height / 4.0) + RADIUS);
+      gdk_draw_line (c->pixmap, style->dark_gc[state],
+		     i * (width / 4.0) + RADIUS, RADIUS,
+		     i * (width / 4.0) + RADIUS, height + RADIUS);
+    }
+
+  gdk_draw_points (c->pixmap, style->fg_gc[state], c->point, c->num_points);
+  if (c->curve_type != GTK_CURVE_TYPE_FREE)
+    for (i = 0; i < c->num_ctlpoints; ++i)
+      {
+	gint x, y;
+
+	if (c->ctlpoint[i][0] < c->min_x)
+	  continue;
+
+	x = project (c->ctlpoint[i][0], c->min_x, c->max_x,
+		     width);
+	y = height -
+	  project (c->ctlpoint[i][1], c->min_y, c->max_y,
+		   height);
+
+	/* draw a bullet: */
+	gdk_draw_arc (c->pixmap, style->fg_gc[state], TRUE, x, y,
+		      RADIUS * 2, RADIUS*2, 0, 360*64);
+      }
+  gdk_draw_pixmap (GTK_WIDGET (c)->window, style->fg_gc[state], c->pixmap,
+		   0, 0, 0, 0, width + RADIUS * 2, height + RADIUS * 2);
+}
+
+static gint
+gtk_curve_graph_events (GtkWidget *widget, GdkEvent *event, GtkCurve *c)
+{
+  GdkCursorType new_type = c->cursor_type;
+  gint i, src, dst, leftbound, rightbound;
+  GdkEventButton *bevent;
+  GdkEventMotion *mevent;
+  GtkWidget *w;
+  gint tx, ty;
+  gint cx, x, y, width, height;
+  gint closest_point = 0;
+  gfloat rx, ry, min_x;
+  guint distance;
+  gint x1, x2, y1, y2;
+
+  w = GTK_WIDGET (c);
+  width = w->allocation.width - RADIUS * 2;
+  height = w->allocation.height - RADIUS * 2;
+
+  /*  get the pointer position  */
+  gdk_window_get_pointer (w->window, &tx, &ty, NULL);
+  x = BOUNDS ((tx - RADIUS), 0, width);
+  y = BOUNDS ((ty - RADIUS), 0, height);
+
+  min_x = c->min_x;
+
+  distance = ~0U;
+  for (i = 0; i < c->num_ctlpoints; ++i)
+    {
+      cx = project (c->ctlpoint[i][0], min_x, c->max_x, width);
+      if ((guint) abs (x - cx) < distance)
+	{
+	  distance = abs (x - cx);
+	  closest_point = i;
+	}
+    }
+
+  switch (event->type)
+    {
+    case GDK_CONFIGURE:
+      if (c->pixmap)
+	gdk_pixmap_destroy (c->pixmap);
+      c->pixmap = 0;
+      /* fall through */
+    case GDK_EXPOSE:
+      if (!c->pixmap)
+	c->pixmap = gdk_pixmap_new (w->window,
+				    w->allocation.width,
+				    w->allocation.height, -1);
+      gtk_curve_draw (c, width, height);
+      break;
+
+    case GDK_BUTTON_PRESS:
+      gtk_grab_add (widget);
+
+      bevent = (GdkEventButton *) event;
+      new_type = GDK_TCROSS;
+
+      switch (c->curve_type)
+	{
+	case GTK_CURVE_TYPE_LINEAR:
+	case GTK_CURVE_TYPE_SPLINE:
+	  if (distance > MIN_DISTANCE)
+	    {
+	      /* insert a new control point */
+	      if (c->num_ctlpoints > 0)
+		{
+		  cx = project (c->ctlpoint[closest_point][0], min_x,
+				c->max_x, width);
+		  if (x > cx)
+		    ++closest_point;
+		}
+	      ++c->num_ctlpoints;
+	      c->ctlpoint =
+		g_realloc (c->ctlpoint,
+			   c->num_ctlpoints * sizeof (*c->ctlpoint));
+	      for (i = c->num_ctlpoints - 1; i > closest_point; --i)
+		memcpy (c->ctlpoint + i, c->ctlpoint + i - 1,
+			sizeof (*c->ctlpoint));
+	    }
+	  c->grab_point = closest_point;
+	  c->ctlpoint[c->grab_point][0] =
+	    unproject (x, min_x, c->max_x, width);
+	  c->ctlpoint[c->grab_point][1] =
+	    unproject (height - y, c->min_y, c->max_y, height);
+
+	  gtk_curve_interpolate (c, width, height);
+	  break;
+
+	case GTK_CURVE_TYPE_FREE:
+	  c->point[x].x = RADIUS + x;
+	  c->point[x].y = RADIUS + y;
+	  c->grab_point = x;
+	  c->last = y;
+	  break;
+	}
+      gtk_curve_draw (c, width, height);
+      break;
+
+    case GDK_BUTTON_RELEASE:
+      gtk_grab_remove (widget);
+
+      /* delete inactive points: */
+      if (c->curve_type != GTK_CURVE_TYPE_FREE)
+	{
+	  for (src = dst = 0; src < c->num_ctlpoints; ++src)
+	    {
+	      if (c->ctlpoint[src][0] >= min_x)
+		{
+		  memcpy (c->ctlpoint + dst, c->ctlpoint + src,
+			  sizeof (*c->ctlpoint));
+		  ++dst;
+		}
+	    }
+	  if (dst < src)
+	    {
+	      c->num_ctlpoints -= (src - dst);
+	      if (c->num_ctlpoints <= 0)
+		{
+		  c->num_ctlpoints = 1;
+		  c->ctlpoint[0][0] = min_x;
+		  c->ctlpoint[0][1] = c->min_y;
+		  gtk_curve_interpolate (c, width, height);
+		  gtk_curve_draw (c, width, height);
+		}
+	      c->ctlpoint =
+		g_realloc (c->ctlpoint,
+			   c->num_ctlpoints * sizeof (*c->ctlpoint));
+	    }
+	}
+      new_type = GDK_FLEUR;
+      c->grab_point = -1;
+      break;
+
+    case GDK_MOTION_NOTIFY:
+      mevent = (GdkEventMotion *) event;
+      if (mevent->is_hint)
+	{
+	  mevent->x = tx;
+	  mevent->y = ty;
+	}
+      switch (c->curve_type)
+	{
+	case GTK_CURVE_TYPE_LINEAR:
+	case GTK_CURVE_TYPE_SPLINE:
+	  if (c->grab_point == -1)
+	    {
+	      /* if no point is grabbed...  */
+	      if (distance <= MIN_DISTANCE)
+		new_type = GDK_FLEUR;
+	      else
+		new_type = GDK_TCROSS;
+	    }
+	  else
+	    {
+	      /* drag the grabbed point  */
+	      new_type = GDK_TCROSS;
+
+	      leftbound = -MIN_DISTANCE;
+	      if (c->grab_point > 0)
+		leftbound = project (c->ctlpoint[c->grab_point - 1][0],
+				     min_x, c->max_x, width);
+
+	      rightbound = width + RADIUS * 2 + MIN_DISTANCE;
+	      if (c->grab_point + 1 < c->num_ctlpoints)
+		rightbound = project (c->ctlpoint[c->grab_point + 1][0],
+				      min_x, c->max_x, width);
+
+	      if (tx <= leftbound || tx >= rightbound
+		  || ty > height + RADIUS * 2 + MIN_DISTANCE
+		  || ty < -MIN_DISTANCE)
+		c->ctlpoint[c->grab_point][0] = min_x - 1.0;
+	      else
+		{
+		  rx = unproject (x, min_x, c->max_x, width);
+		  ry = unproject (height - y, c->min_y, c->max_y, height);
+		  c->ctlpoint[c->grab_point][0] = rx;
+		  c->ctlpoint[c->grab_point][1] = ry;
+		}
+	      gtk_curve_interpolate (c, width, height);
+	      gtk_curve_draw (c, width, height);
+	    }
+	  break;
+
+	case GTK_CURVE_TYPE_FREE:
+	  if (c->grab_point != -1)
+	    {
+	      if (c->grab_point > x)
+		{
+		  x1 = x;
+		  x2 = c->grab_point;
+		  y1 = y;
+		  y2 = c->last;
+		}
+	      else
+		{
+		  x1 = c->grab_point;
+		  x2 = x;
+		  y1 = c->last;
+		  y2 = y;
+		}
+
+	      if (x2 != x1)
+		for (i = x1; i <= x2; i++)
+		  {
+		    c->point[i].x = RADIUS + i;
+		    c->point[i].y = RADIUS +
+		      (y1 + ((y2 - y1) * (i - x1)) / (x2 - x1));
+		  }
+	      else
+		{
+		  c->point[x].x = RADIUS + x;
+		  c->point[x].y = RADIUS + y;
+		}
+	      c->grab_point = x;
+	      c->last = y;
+	      gtk_curve_draw (c, width, height);
+	    }
+	  if (mevent->state & GDK_BUTTON1_MASK)
+	    new_type = GDK_TCROSS;
+	  else
+	    new_type = GDK_PENCIL;
+	  break;
+	}
+      if (new_type != (GdkCursorType) c->cursor_type)
+	{
+	  GdkCursor *cursor;
+
+	  c->cursor_type = new_type;
+
+	  cursor = gdk_cursor_new (c->cursor_type);
+	  gdk_window_set_cursor (w->window, cursor);
+	  gdk_cursor_destroy (cursor);
+	}
+      break;
+
+    default:
+      break;
+    }
+  return FALSE;
+}
+
+void
+gtk_curve_set_curve_type (GtkCurve *c, GtkCurveType new_type)
+{
+  gfloat rx, dx;
+  gint x, i;
+
+  if (new_type != c->curve_type)
+    {
+      gint width, height;
+
+      width  = GTK_WIDGET(c)->allocation.width - RADIUS * 2;
+      height = GTK_WIDGET(c)->allocation.height - RADIUS * 2;
+
+      if (new_type == GTK_CURVE_TYPE_FREE)
+	{
+	  gtk_curve_interpolate (c, width, height);
+	  c->curve_type = new_type;
+	}
+      else if (c->curve_type == GTK_CURVE_TYPE_FREE)
+	{
+	  if (c->ctlpoint)
+	    g_free (c->ctlpoint);
+	  c->num_ctlpoints = 9;
+	  c->ctlpoint = g_malloc (c->num_ctlpoints * sizeof (*c->ctlpoint));
+
+	  rx = 0.0;
+	  dx = (width - 1) / (gfloat) (c->num_ctlpoints - 1);
+
+	  for (i = 0; i < c->num_ctlpoints; ++i, rx += dx)
+	    {
+	      x = (int) (rx + 0.5);
+	      c->ctlpoint[i][0] =
+		unproject (x, c->min_x, c->max_x, width);
+	      c->ctlpoint[i][1] =
+		unproject (RADIUS + height - c->point[x].y,
+			   c->min_y, c->max_y, height);
+	    }
+	  c->curve_type = new_type;
+	  gtk_curve_interpolate (c, width, height);
+	}
+      else
+	{
+	  c->curve_type = new_type;
+	  gtk_curve_interpolate (c, width, height);
+	}
+      gtk_signal_emit (GTK_OBJECT (c), curve_type_changed_signal);
+      gtk_curve_draw (c, width, height);
+    }
+}
+
+static void
+gtk_curve_size_graph (GtkCurve *curve)
+{
+  gint width, height;
+  gfloat aspect;
+
+  width  = (curve->max_x - curve->min_x) + 1;
+  height = (curve->max_y - curve->min_y) + 1;
+  aspect = width / (gfloat) height;
+  if (width > gdk_screen_width () / 4)
+    width  = gdk_screen_width () / 4;
+  if (height > gdk_screen_height () / 4)
+    height = gdk_screen_height () / 4;
+
+  if (aspect < 1.0)
+    width  = height * aspect;
+  else
+    height = width / aspect;
+
+  gtk_drawing_area_size (GTK_DRAWING_AREA (curve),
+			 width + RADIUS * 2, height + RADIUS * 2);
+}
+
+static void
+gtk_curve_reset_vector (GtkCurve *curve)
+{
+  if (curve->ctlpoint)
+    g_free (curve->ctlpoint);
+
+  curve->num_ctlpoints = 2;
+  curve->ctlpoint = g_malloc (2 * sizeof (curve->ctlpoint[0]));
+  curve->ctlpoint[0][0] = curve->min_x;
+  curve->ctlpoint[0][1] = curve->min_y;
+  curve->ctlpoint[1][0] = curve->max_x;
+  curve->ctlpoint[1][1] = curve->max_y;
+
+  if (curve->pixmap)
+    {
+      gint width, height;
+
+      width = GTK_WIDGET (curve)->allocation.width - RADIUS * 2;
+      height = GTK_WIDGET (curve)->allocation.height - RADIUS * 2;
+
+      if (curve->curve_type == GTK_CURVE_TYPE_FREE)
+	{
+	  curve->curve_type = GTK_CURVE_TYPE_LINEAR;
+	  gtk_curve_interpolate (curve, width, height);
+	  curve->curve_type = GTK_CURVE_TYPE_FREE;
+	}
+      else
+	gtk_curve_interpolate (curve, width, height);
+      gtk_curve_draw (curve, width, height);
+    }
+}
+
+void
+gtk_curve_reset (GtkCurve *c)
+{
+  GtkCurveType old_type;
+
+  old_type = c->curve_type;
+  c->curve_type = GTK_CURVE_TYPE_SPLINE;
+  gtk_curve_reset_vector (c);
+
+  if (old_type != GTK_CURVE_TYPE_SPLINE)
+    gtk_signal_emit (GTK_OBJECT (c), curve_type_changed_signal);
+}
+
+void
+gtk_curve_set_gamma (GtkCurve *c, gfloat gamma)
+{
+  gfloat x, one_over_gamma, height, one_over_width;
+  GtkCurveType old_type;
+  gint i;
+
+  if (c->num_points < 2)
+    return;
+
+  old_type = c->curve_type;
+  c->curve_type = GTK_CURVE_TYPE_FREE;
+
+  if (gamma <= 0)
+    one_over_gamma = 1.0;
+  else
+    one_over_gamma = 1.0 / gamma;
+  one_over_width = 1.0 / (c->num_points - 1);
+  height = c->height;
+  for (i = 0; i < c->num_points; ++i)
+    {
+      x = (gfloat) i / (c->num_points - 1);
+      c->point[i].x = RADIUS + i;
+      c->point[i].y =
+	RADIUS + (height * (1.0 - pow (x, one_over_gamma)) + 0.5);
+    }
+
+  if (old_type != GTK_CURVE_TYPE_FREE)
+    gtk_signal_emit (GTK_OBJECT (c), curve_type_changed_signal);
+
+  gtk_curve_draw (c, c->num_points, c->height);
+}
+
+void
+gtk_curve_set_range (GtkCurve *curve,
+		     gfloat min_x, gfloat max_x, gfloat min_y, gfloat max_y)
+{
+  curve->min_x = min_x;
+  curve->max_x = max_x;
+  curve->min_y = min_y;
+  curve->max_y = max_y;
+
+  gtk_curve_size_graph (curve);
+  gtk_curve_reset_vector (curve);
+}
+
+void
+gtk_curve_set_vector (GtkCurve *c, int veclen, gfloat vector[])
+{
+  GtkCurveType old_type;
+  gfloat rx, dx, ry;
+  gint i, height;
+
+  old_type = c->curve_type;
+  c->curve_type = GTK_CURVE_TYPE_FREE;
+
+  if (c->point)
+    height = GTK_WIDGET (c)->allocation.height - RADIUS * 2;
+  else
+    {
+      height = (c->max_y - c->min_y);
+      if (height > gdk_screen_height () / 4)
+	height = gdk_screen_height () / 4;
+
+      c->height = height;
+      c->num_points = veclen;
+      c->point = g_malloc (c->num_points * sizeof (c->point[0]));
+    }
+  rx = 0;
+  dx = (veclen - 1.0) / (c->num_points - 1.0);
+
+  for (i = 0; i < c->num_points; ++i, rx += dx)
+    {
+      ry = vector[(int) (rx + 0.5)];
+      if (ry > c->max_y) ry = c->max_y;
+      if (ry < c->min_y) ry = c->min_y;
+      c->point[i].x = RADIUS + i;
+      c->point[i].y =
+	RADIUS + height - project (ry, c->min_y, c->max_y, height);
+    }
+  if (old_type != GTK_CURVE_TYPE_FREE)
+    gtk_signal_emit (GTK_OBJECT (c), curve_type_changed_signal);
+
+  gtk_curve_draw (c, c->num_points, height);
+}
+
+void
+gtk_curve_get_vector (GtkCurve *c, int veclen, gfloat vector[])
+{
+  gfloat rx, ry, dx, dy, min_x, delta_x, *mem, *xv, *yv, *y2v, prev;
+  gint dst, i, x, next, num_active_ctlpoints = 0, first_active = -1;
+
+  min_x = c->min_x;
+
+  if (c->curve_type != GTK_CURVE_TYPE_FREE)
+    {
+      /* count active points: */
+      prev = min_x - 1.0;
+      for (i = num_active_ctlpoints = 0; i < c->num_ctlpoints; ++i)
+	if (c->ctlpoint[i][0] > prev)
+	  {
+	    if (first_active < 0)
+	      first_active = i;
+	    prev = c->ctlpoint[i][0];
+	    ++num_active_ctlpoints;
+	  }
+
+      /* handle degenerate case: */
+      if (num_active_ctlpoints < 2)
+	{
+	  if (num_active_ctlpoints > 0)
+	    ry = c->ctlpoint[first_active][1];
+	  else
+	    ry = c->min_y;
+	  if (ry < c->min_y) ry = c->min_y;
+	  if (ry > c->max_y) ry = c->max_y;
+	  for (x = 0; x < veclen; ++x)
+	    vector[x] = ry;
+	  return;
+	}
+    }
+
+  switch (c->curve_type)
+    {
+    case GTK_CURVE_TYPE_SPLINE:
+      mem = g_malloc (3 * num_active_ctlpoints * sizeof (gfloat));
+      xv  = mem;
+      yv  = mem + num_active_ctlpoints;
+      y2v = mem + 2*num_active_ctlpoints;
+
+      prev = min_x - 1.0;
+      for (i = dst = 0; i < c->num_ctlpoints; ++i)
+	if (c->ctlpoint[i][0] > prev)
+	  {
+	    prev    = c->ctlpoint[i][0];
+	    xv[dst] = c->ctlpoint[i][0];
+	    yv[dst] = c->ctlpoint[i][1];
+	    ++dst;
+	  }
+
+      spline_solve (num_active_ctlpoints, xv, yv, y2v);
+
+      rx = min_x;
+      dx = (c->max_x - min_x) / (veclen - 1);
+      for (x = 0; x < veclen; ++x, rx += dx)
+	{
+	  ry = spline_eval (num_active_ctlpoints, xv, yv, y2v, rx);
+	  if (ry < c->min_y) ry = c->min_y;
+	  if (ry > c->max_y) ry = c->max_y;
+	  vector[x] = ry;
+	}
+
+      g_free (mem);
+      break;
+
+    case GTK_CURVE_TYPE_LINEAR:
+      dx = (c->max_x - min_x) / (veclen - 1);
+      rx = min_x;
+      ry = c->min_y;
+      dy = 0.0;
+      i  = first_active;
+      for (x = 0; x < veclen; ++x, rx += dx)
+	{
+	  if (rx >= c->ctlpoint[i][0])
+	    {
+	      if (rx > c->ctlpoint[i][0])
+		ry = c->min_y;
+	      dy = 0.0;
+	      next = i + 1;
+	      while (next < c->num_ctlpoints
+		     && c->ctlpoint[next][0] <= c->ctlpoint[i][0])
+		++next;
+	      if (next < c->num_ctlpoints)
+		{
+		  delta_x = c->ctlpoint[next][0] - c->ctlpoint[i][0];
+		  dy = ((c->ctlpoint[next][1] - c->ctlpoint[i][1])
+			/ delta_x);
+		  dy *= dx;
+		  ry = c->ctlpoint[i][1];
+		  i = next;
+		}
+	    }
+	  vector[x] = ry;
+	  ry += dy;
+	}
+      break;
+
+    case GTK_CURVE_TYPE_FREE:
+      if (c->point)
+	{
+	  rx = 0.0;
+	  dx = c->num_points / (double) veclen;
+	  for (x = 0; x < veclen; ++x, rx += dx)
+	    vector[x] = unproject (RADIUS + c->height - c->point[(int) rx].y,
+				   c->min_y, c->max_y,
+				   c->height);
+	}
+      else
+	memset (vector, 0, veclen * sizeof (vector[0]));
+      break;
+    }
+}
+
+GtkWidget*
+gtk_curve_new (void)
+{
+  GtkCurve *curve;
+  gint old_mask;
+
+  curve = gtk_type_new (gtk_curve_get_type ());
+  curve->min_x = 0.0;
+  curve->max_x = 1.0;
+  curve->min_y = 0.0;
+  curve->max_y = 1.0;
+
+  old_mask = gtk_widget_get_events (GTK_WIDGET (curve));
+  gtk_widget_set_events (GTK_WIDGET (curve), old_mask | GRAPH_MASK);
+  gtk_signal_connect (GTK_OBJECT (curve), "event",
+		      (GtkSignalFunc) gtk_curve_graph_events, curve);
+  gtk_curve_size_graph (curve);
+
+  return GTK_WIDGET (curve);
+}
+
+static void
+gtk_curve_destroy (GtkObject *object)
+{
+  GtkCurve *curve;
+
+  g_return_if_fail (object != NULL);
+  g_return_if_fail (GTK_IS_CURVE (object));
+
+  curve = GTK_CURVE (object);
+  if (curve->pixmap)
+    gdk_pixmap_destroy (curve->pixmap);
+  if (curve->point)
+    g_free (curve->point);
+  if (curve->ctlpoint)
+    g_free (curve->ctlpoint);
+
+  if (GTK_OBJECT_CLASS (parent_class)->destroy)
+    (*GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+}