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-rw-r--r--gtk/gtkcurve.c860
1 files changed, 860 insertions, 0 deletions
diff --git a/gtk/gtkcurve.c b/gtk/gtkcurve.c
new file mode 100644
index 000000000..d2b6e08c8
--- /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);
+}