/* 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 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, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

/*

 * 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/. 

 */

#undef GDK_DISABLE_DEPRECATED

#undef GTK_DISABLE_DEPRECATED

#include "config.h"

#include <stdlib.h>

#include <string.h>

#include <math.h>

#include "gtkcurve.h"

#include "gtkdrawingarea.h"

#include "gtkmain.h"

#include "gtkmarshalers.h"

#include "gtkradiobutton.h"

#include "gtktable.h"

#include "gtkprivate.h"

#include "gtkintl.h"

#include "gtkalias.h"

#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)

enum {

  PROP_0,

  PROP_CURVE_TYPE,

  PROP_MIN_X,

  PROP_MAX_X,

  PROP_MIN_Y,

  PROP_MAX_Y

};

static GtkDrawingAreaClass *parent_class = NULL;

static guint 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_get_property  (GObject              *object,

				     guint                 param_id,

				     GValue               *value,

				     GParamSpec           *pspec);

static void gtk_curve_set_property  (GObject              *object,

				     guint                 param_id,

				     const GValue         *value,

				     GParamSpec           *pspec);

static void gtk_curve_finalize     (GObject       *object);

static gint gtk_curve_graph_events (GtkWidget     *widget, 

				    GdkEvent      *event, 

				    GtkCurve      *c);

static void gtk_curve_size_graph   (GtkCurve      *curve);

GType

gtk_curve_get_type (void)

{

  static GType curve_type = 0;

  if (!curve_type)

    {

      const GTypeInfo curve_info =

      {

	sizeof (GtkCurveClass),

	NULL,		/* base_init */

	NULL,		/* base_finalize */

	(GClassInitFunc) gtk_curve_class_init,

	NULL,		/* class_finalize */

	NULL,		/* class_data */

	sizeof (GtkCurve),

	0,		/* n_preallocs */

	(GInstanceInitFunc) gtk_curve_init,

      };

      curve_type = g_type_register_static (GTK_TYPE_DRAWING_AREA, I_("GtkCurve"),

					   &curve_info, 0);

    }

  return curve_type;

}

static void

gtk_curve_class_init (GtkCurveClass *class)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS (class);

  parent_class = g_type_class_peek_parent (class);

  gobject_class->finalize = gtk_curve_finalize;

  gobject_class->set_property = gtk_curve_set_property;

  gobject_class->get_property = gtk_curve_get_property;

  g_object_class_install_property (gobject_class,

				   PROP_CURVE_TYPE,

				   g_param_spec_enum ("curve-type",

						      P_("Curve type"),

						      P_("Is this curve linear, spline interpolated, or free-form"),

						      GTK_TYPE_CURVE_TYPE,

						      GTK_CURVE_TYPE_SPLINE,

						      GTK_PARAM_READWRITE));

  g_object_class_install_property (gobject_class,

				   PROP_MIN_X,

				   g_param_spec_float ("min-x",

						       P_("Minimum X"),

						       P_("Minimum possible value for X"),

						       -G_MAXFLOAT,

						       G_MAXFLOAT,

						       0.0,

						       GTK_PARAM_READWRITE));

  g_object_class_install_property (gobject_class,

				   PROP_MAX_X,

				   g_param_spec_float ("max-x",

						       P_("Maximum X"),

						       P_("Maximum possible X value"),

						       -G_MAXFLOAT,

						       G_MAXFLOAT,

                                                       1.0,

						       GTK_PARAM_READWRITE));

  g_object_class_install_property (gobject_class,

				   PROP_MIN_Y,

				   g_param_spec_float ("min-y",

						       P_("Minimum Y"),

						       P_("Minimum possible value for Y"),

                                                       -G_MAXFLOAT,

						       G_MAXFLOAT,

						       0.0,

						       GTK_PARAM_READWRITE));  

  g_object_class_install_property (gobject_class,

				   PROP_MAX_Y,

				   g_param_spec_float ("max-y",

						       P_("Maximum Y"),

						       P_("Maximum possible value for Y"),

						       -G_MAXFLOAT,

						       G_MAXFLOAT,

						       1.0,

						       GTK_PARAM_READWRITE));

  curve_type_changed_signal =

    g_signal_new (I_("curve-type-changed"),

		   G_OBJECT_CLASS_TYPE (gobject_class),

		   G_SIGNAL_RUN_FIRST,

		   G_STRUCT_OFFSET (GtkCurveClass, curve_type_changed),

		   NULL, NULL,

		   _gtk_marshal_VOID__VOID,

		   G_TYPE_NONE, 0);

}

static void

gtk_curve_init (GtkCurve *curve)

{

  gint old_mask;

  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 = NULL;

  curve->num_ctlpoints = 0;

  curve->ctlpoint = NULL;

  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);

  g_signal_connect (curve, "event",

		    G_CALLBACK (gtk_curve_graph_events), curve);

  gtk_curve_size_graph (curve);

}

static void

gtk_curve_set_property (GObject              *object,

			guint                 prop_id,

			const GValue         *value,

			GParamSpec           *pspec)

{

  GtkCurve *curve = GTK_CURVE (object);

  switch (prop_id)

    {

    case PROP_CURVE_TYPE:

      gtk_curve_set_curve_type (curve, g_value_get_enum (value));

      break;

    case PROP_MIN_X:

      gtk_curve_set_range (curve, g_value_get_float (value), curve->max_x,

			   curve->min_y, curve->max_y);

      break;

    case PROP_MAX_X:

      gtk_curve_set_range (curve, curve->min_x, g_value_get_float (value),

			   curve->min_y, curve->max_y);

      break;	

    case PROP_MIN_Y:

      gtk_curve_set_range (curve, curve->min_x, curve->max_x,

			   g_value_get_float (value), curve->max_y);

      break;

    case PROP_MAX_Y:

      gtk_curve_set_range (curve, curve->min_x, curve->max_x,

			   curve->min_y, g_value_get_float (value));

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

    }

}

static void

gtk_curve_get_property (GObject              *object,

			guint                 prop_id,

			GValue               *value,

			GParamSpec           *pspec)

{

  GtkCurve *curve = GTK_CURVE (object);

  switch (prop_id)

    {

    case PROP_CURVE_TYPE:

      g_value_set_enum (value, curve->curve_type);

      break;

    case PROP_MIN_X:

      g_value_set_float (value, curve->min_x);

      break;

    case PROP_MAX_X:

      g_value_set_float (value, curve->max_x);

      break;

    case PROP_MIN_Y:

      g_value_set_float (value, curve->min_y);

      break;

    case PROP_MAX_Y:

      g_value_set_float (value, curve->max_y);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

    }

}

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;

      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);

    }

  g_free (vector);

}

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: */

  gtk_paint_flat_box (style, c->pixmap, GTK_STATE_NORMAL, GTK_SHADOW_NONE,

		      NULL, GTK_WIDGET (c), "curve_bg",

		      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_drawable (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;

  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;

  gint retval = FALSE;

  w = GTK_WIDGET (c);

  width = w->allocation.width - RADIUS * 2;

  height = w->allocation.height - RADIUS * 2;

  if ((width < 0) || (height < 0))

    return FALSE;

  /*  get the pointer position  */

  gdk_window_get_pointer (w->window, &tx, &ty, NULL);

  x = CLAMP ((tx - RADIUS), 0, width-1);

  y = CLAMP ((ty - RADIUS), 0, height-1);

  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)

	g_object_unref (c->pixmap);

      c->pixmap = NULL;

      /* 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);

      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);

      retval = TRUE;

      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;

      retval = TRUE;

      break;

    case GDK_MOTION_NOTIFY:

      mevent = (GdkEventMotion *) event;

      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_for_display (gtk_widget_get_display (w),

					      c->cursor_type);

	  gdk_window_set_cursor (w->window, cursor);

	  gdk_cursor_unref (cursor);

	}

      retval = TRUE;

      break;

    default:

      break;

    }

  return retval;

}

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)

	{

	  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);

	}

      g_signal_emit (c, curve_type_changed_signal, 0);

      g_object_notify (G_OBJECT (c), "curve-type");

      gtk_curve_draw (c, width, height);

    }

}

static void

gtk_curve_size_graph (GtkCurve *curve)

{

  gint width, height;

  gfloat aspect;

  GdkScreen *screen = gtk_widget_get_screen (GTK_WIDGET (curve)); 

  width  = (curve->max_x - curve->min_x) + 1;

  height = (curve->max_y - curve->min_y) + 1;

  aspect = width / (gfloat) height;

  if (width > gdk_screen_get_width (screen) / 4)

    width  = gdk_screen_get_width (screen) / 4;

  if (height > gdk_screen_get_height (screen) / 4)

    height = gdk_screen_get_height (screen) / 4;

  if (aspect < 1.0)

    width  = height * aspect;

  else

    height = width / aspect;

  gtk_widget_set_size_request (GTK_WIDGET (curve),

			       width + RADIUS * 2,

			       height + RADIUS * 2);

}

static void

gtk_curve_reset_vector (GtkCurve *curve)

{

  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)

    {

       g_signal_emit (c, curve_type_changed_signal, 0);

       g_object_notify (G_OBJECT (c), "curve-type");

    }

}

void

gtk_curve_set_gamma (GtkCurve *c, gfloat gamma)

{

  gfloat x, one_over_gamma, height;

  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;

  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)

    g_signal_emit (c, curve_type_changed_signal, 0);

  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)

{

  g_object_freeze_notify (G_OBJECT (curve));

  if (curve->min_x != min_x) {

     curve->min_x = min_x;

     g_object_notify (G_OBJECT (curve), "min-x");

  }

  if (curve->max_x != max_x) {

     curve->max_x = max_x;

     g_object_notify (G_OBJECT (curve), "max-x");

  }

  if (curve->min_y != min_y) {

     curve->min_y = min_y;

     g_object_notify (G_OBJECT (curve), "min-y");

  }

  if (curve->max_y != max_y) {

     curve->max_y = max_y;

     g_object_notify (G_OBJECT (curve), "max-y");

  }

  g_object_thaw_notify (G_OBJECT (curve));

  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;

  GdkScreen *screen = gtk_widget_get_screen (GTK_WIDGET (c));

  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_get_height (screen) / 4)

	height = gdk_screen_get_height (screen) / 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);