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diff --git a/eel/eel-canvas-util.c b/eel/eel-canvas-util.c
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+/*
+ * Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation
+ * All rights reserved.
+ *
+ * This file is part of the Mate Library.
+ *
+ * The Mate 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.
+ *
+ * The Mate 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 the Mate Library; see the file COPYING.LIB. If not,
+ * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+/*
+ @NOTATION@
+ */
+/* Miscellaneous utility functions for the EelCanvas widget
+ *
+ * EelCanvas is basically a port of the Tk toolkit's most excellent canvas widget. Tk is
+ * copyrighted by the Regents of the University of California, Sun Microsystems, and other parties.
+ *
+ *
+ * Author: Federico Mena <[email protected]>
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <glib.h>
+#include <math.h>
+
+#include "eel-canvas.h"
+#include "eel-canvas-util.h"
+
+/*
+ * Ok, so some systems require magic incantations for M_PI to be defined.
+ * It's not important enough to worry about.
+ */
+#ifndef M_PI
+#define M_PI 3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117
+#endif
+
+/**
+ * eel_canvas_points_new:
+ * @num_points: The number of points to allocate space for in the array.
+ *
+ * Creates a structure that should be used to pass an array of points to
+ * items.
+ *
+ * Return value: A newly-created array of points. It should be filled in
+ * by the user.
+ **/
+EelCanvasPoints *
+eel_canvas_points_new (int num_points)
+{
+ EelCanvasPoints *points;
+
+ g_return_val_if_fail (num_points > 1, NULL);
+
+ points = g_new (EelCanvasPoints, 1);
+ points->num_points = num_points;
+ points->coords = g_new (double, 2 * num_points);
+ points->ref_count = 1;
+
+ return points;
+}
+
+/**
+ * eel_canvas_points_ref:
+ * @points: A canvas points structure.
+ *
+ * Increases the reference count of the specified points structure.
+ *
+ * Return value: The canvas points structure itself.
+ **/
+EelCanvasPoints *
+eel_canvas_points_ref (EelCanvasPoints *points)
+{
+ g_return_val_if_fail (points != NULL, NULL);
+
+ points->ref_count += 1;
+ return points;
+}
+
+/**
+ * eel_canvas_points_free:
+ * @points: A canvas points structure.
+ *
+ * Decreases the reference count of the specified points structure. If it
+ * reaches zero, then the structure is freed.
+ **/
+void
+eel_canvas_points_free (EelCanvasPoints *points)
+{
+ g_return_if_fail (points != NULL);
+
+ points->ref_count -= 1;
+ if (points->ref_count == 0)
+ {
+ g_free (points->coords);
+ g_free (points);
+ }
+}
+
+/**
+ * eel_canvas_get_miter_points:
+ * @x1: X coordinate of the first point
+ * @y1: Y coordinate of the first point
+ * @x2: X coordinate of the second (angle) point
+ * @y2: Y coordinate of the second (angle) point
+ * @x3: X coordinate of the third point
+ * @y3: Y coordinate of the third point
+ * @width: Width of the line
+ * @mx1: The X coordinate of the first miter point is returned here.
+ * @my1: The Y coordinate of the first miter point is returned here.
+ * @mx2: The X coordinate of the second miter point is returned here.
+ * @my2: The Y coordinate of the second miter point is returned here.
+ *
+ * Given three points forming an angle, computes the coordinates of the inside
+ * and outside points of the mitered corner formed by a line of a given width at
+ * that angle.
+ *
+ * Return value: FALSE if the angle is less than 11 degrees (this is the same
+ * threshold as X uses. If this occurs, the return points are not modified.
+ * Otherwise, returns TRUE.
+ **/
+int
+eel_canvas_get_miter_points (double x1, double y1, double x2, double y2, double x3, double y3,
+ double width,
+ double *mx1, double *my1, double *mx2, double *my2)
+{
+ double theta1; /* angle of segment p2-p1 */
+ double theta2; /* angle of segment p2-p3 */
+ double theta; /* angle between line segments */
+ double theta3; /* angle that bisects theta1 and theta2 and points to p1 */
+ double dist; /* distance of miter points from p2 */
+ double dx, dy; /* x and y offsets corresponding to dist */
+
+ double ELEVEN_DEGREES = 11.0 * M_PI / 180.0;
+
+ /* Degenerate cases. */
+ if ((x1 == x2 && y1 == y2) || (x2 == x3 && y2 == y3))
+ return FALSE;
+
+ theta1 = atan2 (y1 - y2, x1 - x2);
+ theta2 = atan2 (y3 - y2, x3 - x2);
+ theta = theta1 - theta2;
+
+ /* Normalize to (-pi; pi]. */
+ if (theta > M_PI)
+ theta -= 2.0 * M_PI;
+ else if (theta <= -M_PI)
+ theta += 2.0 * M_PI;
+
+ if (fabs (theta) < ELEVEN_DEGREES)
+ return FALSE;
+
+ dist = fabs (0.5 * width / sin (0.5 * theta));
+
+ theta3 = (theta1 + theta2) / 2.0;
+ if (sin (theta3 - theta1) > 0.0)
+ theta3 += M_PI;
+
+ dx = dist * cos (theta3);
+ dy = dist * sin (theta3);
+
+ *mx1 = x2 + dx;
+ *mx2 = x2 - dx;
+ *my1 = y2 + dy;
+ *my2 = y2 - dy;
+
+ return TRUE;
+}
+
+/**
+ * eel_canvas_get_butt_points:
+ * @x1: X coordinate of first point in the line
+ * @y1: Y cooordinate of first point in the line
+ * @x2: X coordinate of second point (endpoint) of the line
+ * @y2: Y coordinate of second point (endpoint) of the line
+ * @width: Width of the line
+ * @project: Whether the butt points should project out by width/2 distance
+ * @bx1: X coordinate of first butt point is returned here
+ * @by1: Y coordinate of first butt point is returned here
+ * @bx2: X coordinate of second butt point is returned here
+ * @by2: Y coordinate of second butt point is returned here
+ *
+ * Computes the butt points of a line segment.
+ **/
+void
+eel_canvas_get_butt_points (double x1, double y1, double x2, double y2,
+ double width, int project,
+ double *bx1, double *by1, double *bx2, double *by2)
+{
+ double length;
+ double dx, dy;
+
+ width *= 0.5;
+ dx = x2 - x1;
+ dy = y2 - y1;
+ length = sqrt (dx * dx + dy * dy);
+
+ if (length < EEL_CANVAS_EPSILON)
+ {
+ *bx1 = *bx2 = x2;
+ *by1 = *by2 = y2;
+ }
+ else
+ {
+ dx = -width * (y2 - y1) / length;
+ dy = width * (x2 - x1) / length;
+
+ *bx1 = x2 + dx;
+ *bx2 = x2 - dx;
+ *by1 = y2 + dy;
+ *by2 = y2 - dy;
+
+ if (project)
+ {
+ *bx1 += dy;
+ *bx2 += dy;
+ *by1 -= dx;
+ *by2 -= dx;
+ }
+ }
+}
+
+/**
+ * eel_canvas_polygon_to_point:
+ * @poly: Vertices of the polygon. X coordinates are in the even indices, and Y
+ * coordinates are in the odd indices
+ * @num_points: Number of points in the polygon
+ * @x: X coordinate of the point
+ * @y: Y coordinate of the point
+ *
+ * Computes the distance between a point and a polygon.
+ *
+ * Return value: The distance from the point to the polygon, or zero if the
+ * point is inside the polygon.
+ **/
+double
+eel_canvas_polygon_to_point (double *poly, int num_points, double x, double y)
+{
+ double best;
+ int intersections;
+ int i;
+ double *p;
+ double dx, dy;
+
+ /* Iterate through all the edges in the polygon, updating best and intersections.
+ *
+ * When computing intersections, include left X coordinate of line within its range, but not
+ * Y coordinate. Otherwise if the point lies exactly below a vertex we'll count it as two
+ * intersections.
+ */
+
+ best = 1.0e36;
+ if (poly == NULL)
+ return best;
+
+ intersections = 0;
+
+ for (i = num_points, p = poly; i > 1; i--, p += 2)
+ {
+ double px, py, dist;
+
+ /* Compute the point on the current edge closest to the point and update the
+ * intersection count. This must be done separately for vertical edges, horizontal
+ * edges, and others.
+ */
+
+ if (p[2] == p[0])
+ {
+ /* Vertical edge */
+
+ px = p[0];
+
+ if (p[1] >= p[3])
+ {
+ py = MIN (p[1], y);
+ py = MAX (py, p[3]);
+ }
+ else
+ {
+ py = MIN (p[3], y);
+ py = MAX (py, p[1]);
+ }
+ }
+ else if (p[3] == p[1])
+ {
+ /* Horizontal edge */
+
+ py = p[1];
+
+ if (p[0] >= p[2])
+ {
+ px = MIN (p[0], x);
+ px = MAX (px, p[2]);
+
+ if ((y < py) && (x < p[0]) && (x >= p[2]))
+ intersections++;
+ }
+ else
+ {
+ px = MIN (p[2], x);
+ px = MAX (px, p[0]);
+
+ if ((y < py) && (x < p[2]) && (x >= p[0]))
+ intersections++;
+ }
+ }
+ else
+ {
+ double m1, b1, m2, b2;
+ int lower;
+
+ /* Diagonal edge. Convert the edge to a line equation (y = m1*x + b1), then
+ * compute a line perpendicular to this edge but passing through the point,
+ * (y = m2*x + b2).
+ */
+
+ m1 = (p[3] - p[1]) / (p[2] - p[0]);
+ b1 = p[1] - m1 * p[0];
+
+ m2 = -1.0 / m1;
+ b2 = y - m2 * x;
+
+ px = (b2 - b1) / (m1 - m2);
+ py = m1 * px + b1;
+
+ if (p[0] > p[2])
+ {
+ if (px > p[0])
+ {
+ px = p[0];
+ py = p[1];
+ }
+ else if (px < p[2])
+ {
+ px = p[2];
+ py = p[3];
+ }
+ }
+ else
+ {
+ if (px > p[2])
+ {
+ px = p[2];
+ py = p[3];
+ }
+ else if (px < p[0])
+ {
+ px = p[0];
+ py = p[1];
+ }
+ }
+
+ lower = (m1 * x + b1) > y;
+
+ if (lower && (x >= MIN (p[0], p[2])) && (x < MAX (p[0], p[2])))
+ intersections++;
+ }
+
+ /* Compute the distance to the closest point, and see if that is the best so far */
+
+ dx = x - px;
+ dy = y - py;
+ dist = sqrt (dx * dx + dy * dy);
+ if (dist < best)
+ best = dist;
+ }
+
+ /* We've processed all the points. If the number of intersections is odd, the point is
+ * inside the polygon.
+ */
+
+ if (intersections & 0x1)
+ return 0.0;
+ else
+ return best;
+}
+
+/**
+ * eel_canvas_item_reset_bounds:
+ * @item: A canvas item
+ *
+ * Resets the bounding box of a canvas item to an empty rectangle.
+ **/
+void
+eel_canvas_item_reset_bounds (EelCanvasItem *item)
+{
+ item->x1 = 0.0;
+ item->y1 = 0.0;
+ item->x2 = 0.0;
+ item->y2 = 0.0;
+}
+
+/**
+ * eel_canvas_update_bbox:
+ * @canvas: the canvas needing update
+ * @x1: Left coordinate of the new bounding box
+ * @y1: Top coordinate of the new bounding box
+ * @x2: Right coordinate of the new bounding box
+ * @y2: Bottom coordinate of the new bounding box
+ *
+ * Sets the bbox to the new value, requesting full repaint.
+ **/
+void
+eel_canvas_update_bbox (EelCanvasItem *item, int x1, int y1, int x2, int y2)
+{
+ eel_canvas_item_request_redraw (item);
+ item->x1 = x1;
+ item->y1 = y1;
+ item->x2 = x2;
+ item->y2 = y2;
+ eel_canvas_item_request_redraw (item);
+}
+