path: root/libgnomecanvas/gnome-canvas-shape.c

/* Generic bezier shape item for GnomeCanvasWidget.  Most code taken
 * from gnome-canvas-bpath but made into a shape item.
 *
 * GnomeCanvas 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.
 *
 * Copyright (C) 1998,1999 The Free Software Foundation
 *
 * Authors: Federico Mena <federico@nuclecu.unam.mx>
 *          Raph Levien <raph@acm.org>
 *          Lauris Kaplinski <lauris@ximian.com>
 *          Miguel de Icaza <miguel@kernel.org>
 *          Cody Russell <bratsche@gnome.org>
 *          Rusty Conover <rconover@bangtail.net>
 */

/* These includes are set up for standalone compile. If/when this codebase
   is integrated into libgnomeui, the includes will need to change. */

#include <math.h>
#include <string.h>

#include <gtk/gtk.h>
#include "gnome-canvas.h"
#include "gnome-canvas-util.h"

#include "gnome-canvas-shape.h"
#include "gnome-canvas-shape-private.h"
#include "gnome-canvas-path-def.h"

#include <libart_lgpl/art_rect.h>
#include <libart_lgpl/art_vpath.h>
#include <libart_lgpl/art_bpath.h>
#include <libart_lgpl/art_vpath_bpath.h>
#include <libart_lgpl/art_svp.h>
#include <libart_lgpl/art_svp_point.h>
#include <libart_lgpl/art_svp_vpath.h>
#include <libart_lgpl/art_vpath_dash.h>
#include <libart_lgpl/art_svp_wind.h>
#include <libart_lgpl/art_svp_intersect.h>
#include <libart_lgpl/art_rect_svp.h>

enum {
    PROP_0,
    PROP_FILL_COLOR,
    PROP_FILL_COLOR_GDK,
    PROP_FILL_COLOR_RGBA,
    PROP_OUTLINE_COLOR,
    PROP_OUTLINE_COLOR_GDK,
    PROP_OUTLINE_COLOR_RGBA,
    PROP_WIDTH_PIXELS,
    PROP_WIDTH_UNITS,
    PROP_CAP_STYLE,
    PROP_JOIN_STYLE,
    PROP_WIND,
    PROP_MITERLIMIT,
    PROP_DASH
};

static void gnome_canvas_shape_destroy      (GnomeCanvasItem       *object);
static void gnome_canvas_shape_set_property (GObject               *object,
                         guint                  param_id,
                         const GValue          *value,
                                             GParamSpec            *pspec);
static void gnome_canvas_shape_get_property (GObject               *object,
                         guint                  param_id,
                         GValue                *value,
                                             GParamSpec            *pspec);

static void   gnome_canvas_shape_update      (GnomeCanvasItem *item, gdouble *affine, ArtSVP *clip_path, gint flags);
static void   gnome_canvas_shape_realize     (GnomeCanvasItem *item);
static void   gnome_canvas_shape_unrealize   (GnomeCanvasItem *item);
static void   gnome_canvas_shape_draw        (GnomeCanvasItem *item, GdkDrawable *drawable,
                                              gint x, gint y, gint width, gint height);
static GnomeCanvasItem *gnome_canvas_shape_point (GnomeCanvasItem *item, gdouble x, gdouble y,
                                              gint cx, gint cy);
static void   gnome_canvas_shape_bounds      (GnomeCanvasItem *item,
                          gdouble *x1, gdouble *y1, gdouble *x2, gdouble *y2);

static gulong get_pixel_from_rgba (GnomeCanvasItem *item, guint32 rgba_color);
static guint32 get_rgba_from_color (GdkColor * color);
static void set_gc_foreground (GdkGC *gc, gulong pixel);
static void gcbp_ensure_gdk (GnomeCanvasShape * bpath);
static void gcbp_destroy_gdk (GnomeCanvasShape * bpath);
static void gcbp_ensure_mask (GnomeCanvasShape * bpath, gint width, gint height);
static void gcbp_draw_ctx_unref (GCBPDrawCtx * ctx);

G_DEFINE_TYPE (GnomeCanvasShape, gnome_canvas_shape, GNOME_TYPE_CANVAS_ITEM)

static void
gnome_canvas_shape_class_init (GnomeCanvasShapeClass *class)
{
    GObjectClass         *gobject_class;
    GnomeCanvasItemClass *item_class;

    gobject_class = (GObjectClass *) class;
    item_class = (GnomeCanvasItemClass *) class;

    /* when this gets checked into libgnomeui, change the
           GTK_TYPE_POINTER to GTK_TYPE_GNOME_CANVAS_SHAPE, and add an
           entry to gnome-boxed.defs */

    gobject_class->set_property = gnome_canvas_shape_set_property;
    gobject_class->get_property = gnome_canvas_shape_get_property;

        g_object_class_install_property (gobject_class,
                                         PROP_FILL_COLOR,
                                         g_param_spec_string ("fill_color", NULL, NULL,
                                                              NULL,
                                                              (G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_FILL_COLOR_GDK,
                                         g_param_spec_boxed ("fill_color_gdk", NULL, NULL,
                                                             GDK_TYPE_COLOR,
                                                             (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_FILL_COLOR_RGBA,
                                         g_param_spec_uint ("fill_color_rgba", NULL, NULL,
                                                            0, G_MAXUINT, 0,
                                                            (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_OUTLINE_COLOR,
                                         g_param_spec_string ("outline_color", NULL, NULL,
                                                              NULL,
                                                              (G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_OUTLINE_COLOR_GDK,
                                         g_param_spec_boxed ("outline_color_gdk", NULL, NULL,
                                                             GDK_TYPE_COLOR,
                                                             (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_OUTLINE_COLOR_RGBA,
                                         g_param_spec_uint ("outline_color_rgba", NULL, NULL,
                                                            0, G_MAXUINT, 0,
                                                            (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_WIDTH_PIXELS,
                                         g_param_spec_uint ("width_pixels", NULL, NULL,
                                                            0, G_MAXUINT, 0,
                                                            (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_WIDTH_UNITS,
                                         g_param_spec_double ("width_units", NULL, NULL,
                                                              0.0, G_MAXDOUBLE, 0.0,
                                                              (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_CAP_STYLE,
                                         g_param_spec_enum ("cap_style", NULL, NULL,
                                                            GDK_TYPE_CAP_STYLE,
                                                            GDK_CAP_BUTT,
                                                            (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_JOIN_STYLE,
                                         g_param_spec_enum ("join_style", NULL, NULL,
                                                            GDK_TYPE_JOIN_STYLE,
                                                            GDK_JOIN_MITER,
                                                            (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_WIND,
                                         g_param_spec_uint ("wind", NULL, NULL,
                                                            0, G_MAXUINT, 0,
                                                            (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_MITERLIMIT,
                                         g_param_spec_double ("miterlimit", NULL, NULL,
                                                              0.0, G_MAXDOUBLE, 0.0,
                                                              (G_PARAM_READABLE | G_PARAM_WRITABLE)));
        g_object_class_install_property (gobject_class,
                                         PROP_DASH,
                                         g_param_spec_pointer ("dash", NULL, NULL,
                                                               (G_PARAM_READABLE | G_PARAM_WRITABLE)));

    item_class->destroy = gnome_canvas_shape_destroy;
    item_class->update = gnome_canvas_shape_update;
    item_class->realize = gnome_canvas_shape_realize;
    item_class->unrealize = gnome_canvas_shape_unrealize;
    item_class->draw = gnome_canvas_shape_draw;
    item_class->point = gnome_canvas_shape_point;
    item_class->bounds = gnome_canvas_shape_bounds;

        g_type_class_add_private (class, sizeof (GnomeCanvasShapePriv));
}

static void
gnome_canvas_shape_init (GnomeCanvasShape *shape)
{
    shape->priv = G_TYPE_INSTANCE_GET_PRIVATE (shape,
                                                   GNOME_TYPE_CANVAS_SHAPE,
                                                   GnomeCanvasShapePriv);

    shape->priv->path = NULL;

    shape->priv->scale = 1.0;

    shape->priv->fill_set = FALSE;
    shape->priv->outline_set = FALSE;
    shape->priv->width_pixels = FALSE;

    shape->priv->width = 1.0;

    shape->priv->fill_rgba = 0x0000003f;
    shape->priv->outline_rgba = 0x0000007f;

    shape->priv->cap = GDK_CAP_BUTT;
    shape->priv->join = GDK_JOIN_MITER;
    shape->priv->wind = ART_WIND_RULE_ODDEVEN;
    shape->priv->miterlimit = 10.43;       /* X11 default */

    shape->priv->dash.n_dash = 0;
    shape->priv->dash.dash = NULL;

    shape->priv->fill_svp = NULL;
    shape->priv->outline_svp = NULL;

    shape->priv->gdk = NULL;
}

static void
gnome_canvas_shape_destroy (GnomeCanvasItem *object)
{
    GnomeCanvasShape *shape;
    GnomeCanvasShapePriv *priv;

    g_return_if_fail (object != NULL);
    g_return_if_fail (GNOME_IS_CANVAS_SHAPE (object));

        shape = GNOME_CANVAS_SHAPE (object);

        priv = shape->priv;
        if (priv->gdk) gcbp_destroy_gdk (shape);

        if (priv->path) gnome_canvas_path_def_unref (priv->path);

        if (priv->dash.dash) g_free (priv->dash.dash);
        if (priv->fill_svp) art_svp_free (priv->fill_svp);
        if (priv->outline_svp) art_svp_free (priv->outline_svp);

    if (GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->destroy)
        GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->destroy (object);
}

/**
 * gnome_canvas_shape_set_path_def:
 * @shape: a GnomeCanvasShape
 * @def: a GnomeCanvasPathDef
 *
 * This function sets the the GnomeCanvasPathDef used by the
 * GnomeCanvasShape. Notice, that it does not request updates, as
 * it is meant to be used from item implementations, from inside
 * update queue.
 */

void
gnome_canvas_shape_set_path_def (GnomeCanvasShape *shape, GnomeCanvasPathDef *def)
{
    GnomeCanvasShapePriv *priv;

    g_return_if_fail (shape != NULL);
    g_return_if_fail (GNOME_IS_CANVAS_SHAPE (shape));

    priv = shape->priv;

    if (priv->path) {
        gnome_canvas_path_def_unref (priv->path);
        priv->path = NULL;
    }

    if (def) {
        priv->path = gnome_canvas_path_def_duplicate (def);
    }
}

static void
gnome_canvas_shape_set_property (GObject      *object,
                                 guint         param_id,
                                 const GValue *value,
                                 GParamSpec   *pspec)
{
    GnomeCanvasItem         *item;
    GnomeCanvasShape        *shape;
    GnomeCanvasShapePriv    *priv;
    GnomeCanvasShapePrivGdk *gdk;
    GdkColor                 color;
    GdkColor                *colorptr;
    ArtVpathDash            *dash;

    item = GNOME_CANVAS_ITEM (object);
    shape = GNOME_CANVAS_SHAPE (object);
    priv = shape->priv;

        gcbp_ensure_gdk (shape);
        gdk = priv->gdk;

    switch (param_id) {
    case PROP_FILL_COLOR:
        if (gnome_canvas_get_color (item->canvas, g_value_get_string (value), &color)) {
            priv->fill_set = TRUE;
            priv->fill_rgba = get_rgba_from_color (&color);
            if (gdk) gdk->fill_pixel = color.pixel;
        } else if (priv->fill_set)
            priv->fill_set = FALSE;
        else
            break;

        gnome_canvas_item_request_update (item);
        break;

    case PROP_FILL_COLOR_GDK:
        colorptr = g_value_get_boxed (value);
        if (colorptr != NULL) {
            priv->fill_set = TRUE;
            priv->fill_rgba = get_rgba_from_color (colorptr);
            if (gdk) {
                GdkColormap *colormap = gtk_widget_get_colormap (GTK_WIDGET (item->canvas));
                GdkColor tmp = *colorptr;
                gdk_rgb_find_color (colormap, &tmp);
                gdk->fill_pixel = tmp.pixel;
            }
        } else if (priv->fill_set)
            priv->fill_set = FALSE;
        else
            break;

        gnome_canvas_item_request_update (item);
        break;

    case PROP_FILL_COLOR_RGBA:
        priv->fill_set = TRUE;
        priv->fill_rgba = g_value_get_uint (value);
        if (gdk) gdk->fill_pixel = get_pixel_from_rgba (item, priv->fill_rgba);

        gnome_canvas_item_request_update (item);
        break;

    case PROP_OUTLINE_COLOR:
        if (gnome_canvas_get_color (item->canvas, g_value_get_string (value), &color)) {
            priv->outline_set = TRUE;
            priv->outline_rgba = get_rgba_from_color (&color);
            if (gdk) gdk->outline_pixel = color.pixel;
        } else if (priv->outline_set)
            priv->outline_set = FALSE;
        else
            break;

        gnome_canvas_item_request_update (item);
        break;

    case PROP_OUTLINE_COLOR_GDK:
        colorptr = g_value_get_boxed (value);
        if (colorptr != NULL) {
            priv->outline_set = TRUE;
            priv->outline_rgba = get_rgba_from_color (colorptr);
            if (gdk) {
                GdkColormap *colormap = gtk_widget_get_colormap (GTK_WIDGET (item->canvas));
                GdkColor tmp = *colorptr;
                gdk_rgb_find_color (colormap, &tmp);
                gdk->outline_pixel = tmp.pixel;
            }
        } else if (priv->outline_set)
            priv->outline_set = FALSE;
        else
            break;

        gnome_canvas_item_request_update (item);
        break;

    case PROP_OUTLINE_COLOR_RGBA:
        priv->outline_set = TRUE;
        priv->outline_rgba = g_value_get_uint (value);
        if (gdk) gdk->outline_pixel = get_pixel_from_rgba (item, priv->outline_rgba);

        gnome_canvas_item_request_update (item);
        break;

    case PROP_WIDTH_PIXELS:
        priv->width = g_value_get_uint (value);
        priv->width_pixels = TRUE;

        gnome_canvas_item_request_update (item);
        break;

    case PROP_WIDTH_UNITS:
        priv->width = fabs (g_value_get_double (value));
        priv->width_pixels = FALSE;

        gnome_canvas_item_request_update (item);
        break;

    case PROP_WIND:
        priv->wind = g_value_get_uint (value);
        gnome_canvas_item_request_update (item);
        break;

    case PROP_CAP_STYLE:
        priv->cap = g_value_get_enum (value);
        gnome_canvas_item_request_update (item);
        break;

    case PROP_JOIN_STYLE:
        priv->join = g_value_get_enum (value);
        gnome_canvas_item_request_update (item);
        break;

    case PROP_MITERLIMIT:
        priv->miterlimit = g_value_get_double (value);
        gnome_canvas_item_request_update (item);
        break;

    case PROP_DASH:
        dash = g_value_get_pointer (value);
        if (priv->dash.dash) g_free (priv->dash.dash);
        priv->dash.dash = NULL;

        if (dash) {
            priv->dash.offset = dash->offset;
            priv->dash.n_dash = dash->n_dash;
            if (dash->dash != NULL) {
                priv->dash.dash = g_new (double, dash->n_dash);
                memcpy (priv->dash.dash, dash->dash, dash->n_dash * sizeof (gdouble));
            }
        }
        gnome_canvas_item_request_update (item);
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, param_id, pspec);
        break;
    }
}

/* Allocates a GdkColor structure filled with the specified pixel, and
 * puts it into the specified value for returning it in the get_property
 * method.
 */

static void
get_color_value (GnomeCanvasShape *shape, gulong pixel, GValue *value)
{
    GnomeCanvas *canvas = GNOME_CANVAS_ITEM (shape)->canvas;
    GdkColormap *colormap = gtk_widget_get_colormap (GTK_WIDGET (canvas));
    GdkColor color;

    gdk_colormap_query_color (colormap, pixel, &color);
    g_value_set_boxed (value, &color);
}

/**
 * gnome_canvas_shape_get_path_def:
 * @shape: a GnomeCanvasShape
 *
 * This function returns the #GnomeCanvasPathDef that the shape
 * currently uses.  It adds a reference to the #GnomeCanvasPathDef and
 * returns it, if there is not a #GnomeCanvasPathDef set for the shape
 * it returns NULL.
 *
 * Returns: a #GnomeCanvasPathDef or NULL if none is set for the shape.
 */

GnomeCanvasPathDef *
gnome_canvas_shape_get_path_def (GnomeCanvasShape *shape)
{
    GnomeCanvasShapePriv *priv;

    g_return_val_if_fail (shape != NULL, NULL);
    g_return_val_if_fail (GNOME_IS_CANVAS_SHAPE (shape), NULL);

    priv = shape->priv;

    if (priv->path) {
        gnome_canvas_path_def_ref (priv->path);
        return priv->path;
    }

    return NULL;
}

static void
gnome_canvas_shape_get_property (GObject     *object,
                                 guint        param_id,
                                 GValue      *value,
                                 GParamSpec  *pspec)
{
    GnomeCanvasShape        *shape = GNOME_CANVAS_SHAPE (object);
    GnomeCanvasShapePriv    *priv = shape->priv;
    GnomeCanvasShapePrivGdk *gdk;

        gcbp_ensure_gdk (shape);
        gdk = priv->gdk;

    switch (param_id) {
    case PROP_FILL_COLOR_GDK:
        if (gdk) {
            get_color_value (shape, gdk->fill_pixel, value);
        } else {
            get_color_value (shape, 0, value);
        }
        break;

    case PROP_OUTLINE_COLOR_GDK:
        if (gdk) {
            get_color_value (shape, gdk->outline_pixel, value);
        } else {
            get_color_value (shape, 0, value);
        }
        break;

    case PROP_FILL_COLOR_RGBA:
        g_value_set_uint (value, priv->fill_rgba);
        break;

    case PROP_OUTLINE_COLOR_RGBA:
        g_value_set_uint (value, priv->outline_rgba);
        break;

    case PROP_WIND:
        g_value_set_uint (value, priv->wind);
        break;

    case PROP_CAP_STYLE:
        g_value_set_enum (value, priv->cap);
        break;

    case PROP_JOIN_STYLE:
        g_value_set_enum (value, priv->join);
        break;

    case PROP_WIDTH_PIXELS:
        g_value_set_uint (value, priv->width);
        break;

    case PROP_WIDTH_UNITS:
        g_value_set_double (value, priv->width);
        break;

    case PROP_MITERLIMIT:
        g_value_set_double (value, priv->miterlimit);
        break;

    case PROP_DASH:
        g_value_set_pointer (value, &priv->dash);
        break;

    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, param_id, pspec);
        break;
    }
}

static void
gnome_canvas_shape_realize (GnomeCanvasItem *item)
{
    GnomeCanvasShape *shape;
        GtkLayout *layout;
        GdkWindow *bin_window;

    shape = GNOME_CANVAS_SHAPE (item);

    if (GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->realize)
        GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->realize (item);

        gcbp_ensure_gdk (shape);

        layout = GTK_LAYOUT (item->canvas);
        bin_window = gtk_layout_get_bin_window (layout);

        g_assert (bin_window != NULL);

        shape->priv->gdk->fill_gc = gdk_gc_new (bin_window);
        shape->priv->gdk->outline_gc = gdk_gc_new (bin_window);
}

static void
gnome_canvas_shape_unrealize (GnomeCanvasItem *item)
{
    GnomeCanvasShape *shape;

    shape = GNOME_CANVAS_SHAPE (item);

        g_assert (shape->priv->gdk != NULL);

        g_object_unref (shape->priv->gdk->fill_gc);
        shape->priv->gdk->fill_gc = NULL;

        g_object_unref (shape->priv->gdk->outline_gc);
        shape->priv->gdk->outline_gc = NULL;

    if (GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->unrealize)
        GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->unrealize (item);
}

static void
gnome_canvas_shape_draw (GnomeCanvasItem *item,
    GdkDrawable *drawable,
    gint x,
    gint y,
    gint width,
    gint height)
{
    static GdkPoint * dpoints = NULL;
    static gint num_dpoints = 0;

    GnomeCanvasShape * shape;
    GnomeCanvasShapePriv * priv;
    GnomeCanvasShapePrivGdk * gdk;
    gint i, pos, len;
    GSList * l;

    shape = GNOME_CANVAS_SHAPE (item);
    priv = shape->priv;

    /* We have to be realized, so gdk struct should exist! */

    gdk = shape->priv->gdk;
    g_assert (gdk != NULL);

    /* Build temporary point list, translated by -x, -y */

    if (dpoints == NULL) {
        dpoints = g_new (GdkPoint, gdk->num_points);
        num_dpoints = gdk->num_points;
    } else if (num_dpoints < gdk->num_points) {
        dpoints = g_renew (GdkPoint, dpoints, gdk->num_points);
        num_dpoints = gdk->num_points;
    }

    for (i = 0; i < gdk->num_points; i++) {
        dpoints[i].x = gdk->points[i].x - x;
        dpoints[i].y = gdk->points[i].y - y;
    }

    if (priv->fill_set) {

        /* Ensure, that we have mask and it is big enough */

        gcbp_ensure_mask (shape, width, height);

        /* Clear mask */

        gdk_draw_rectangle (gdk->ctx->mask,
            gdk->ctx->clear_gc,
            TRUE,
            0, 0,
            width, height);

        /* Draw subpaths, using XOR gc */

        pos = 0;

        for (l = gdk->closed_paths; l != NULL; l = l->next) {
            len = GPOINTER_TO_INT (l->data);

            gdk_draw_polygon (gdk->ctx->mask,
                gdk->ctx->xor_gc,
                TRUE,
                &dpoints[pos],
                len);

            pos += len;
        }

        /* Set bitmap to clipping mask */

        gdk_gc_set_clip_mask (gdk->fill_gc, gdk->ctx->mask);

        /* Draw clipped rect to drawable */

        gdk_draw_rectangle (drawable,
            gdk->fill_gc,
            TRUE,
            0, 0,
            width, height);
    }

    if (priv->outline_set) {

        /* Draw subpaths */

        pos = 0;

        for (l = gdk->closed_paths; l != NULL; l = l->next) {
            len = GPOINTER_TO_INT (l->data);

            gdk_draw_polygon (drawable,
                      gdk->outline_gc,
                      FALSE,
                      &dpoints[pos],
                      len);

            pos += len;
        }

        for (l = gdk->open_paths; l != NULL; l = l->next) {
            len = GPOINTER_TO_INT (l->data);

            gdk_draw_lines (drawable,
                    gdk->outline_gc,
                    &dpoints[pos],
                    len);

            pos += len;
        }
    }
}

#define GDK_POINTS_BLOCK 32

static void
gnome_canvas_shape_ensure_gdk_points (GnomeCanvasShapePrivGdk *gdk, gint num)
{
    if (gdk->len_points < gdk->num_points + num) {
        gdk->len_points = MAX (gdk->len_points + GDK_POINTS_BLOCK, gdk->len_points + num);
        gdk->points = g_renew (GdkPoint, gdk->points, gdk->len_points);
    }
}

static void
gnome_canvas_shape_update_gdk (GnomeCanvasShape * shape, gdouble * affine, ArtSVP * clip, gint flags)
{
    GnomeCanvasShapePriv * priv;
    GnomeCanvasShapePrivGdk * gdk;
    gint x1 = 0, y1 = 0, x2 = 0, y2 = 0;
    gboolean bbox_set = FALSE;
    gint width = 0; /* silence gcc */

    priv = shape->priv;
    gdk = priv->gdk;
    g_assert (gdk != NULL);

    if (priv->outline_set) {
        GdkLineStyle style;

        if (priv->width_pixels) {
            width = (gint) floor (priv->width + 0.5);
            /* Never select 0 pixels unless the user asked for it,
             * since that is the X11 zero width lines are non-specified */
            if (priv->width_pixels != 0 && width == 0) {
                width = 1;
            }
        } else {
            width = (gint) floor ((priv->width * priv->scale) + 0.5);
            /* Never select 0 pixels unless the user asked for it,
             * since that is the X11 zero width lines are non-speciifed */
            if (priv->width != 0 && width == 0) {
                width = 1;
            }
        }

        /* If dashed, set it in GdkGC */

        if ((shape->priv->dash.dash != NULL) && (shape->priv->dash.n_dash > 0)) {
            gint8 * dash_list;
            gint i;

            dash_list = g_new (gint8, shape->priv->dash.n_dash);

            for (i = 0; i < priv->dash.n_dash; i++) {
                dash_list[i] = (gint8) shape->priv->dash.dash[i];
            }

            gdk_gc_set_dashes (gdk->outline_gc,
                (gint) priv->dash.offset,
                dash_list,
                priv->dash.n_dash);

            g_free (dash_list);

            style = GDK_LINE_ON_OFF_DASH;
        } else {
            style = GDK_LINE_SOLID;
        }

        /* Set line width, cap, join */
        if (gdk->outline_gc) {

            gdk_gc_set_line_attributes (gdk->outline_gc,
                            width,
                            style,
                            priv->cap,
                            priv->join);

            set_gc_foreground (gdk->outline_gc, gdk->outline_pixel);
        }
    }

    if (priv->fill_set) {

        if (gdk->fill_gc) {
            set_gc_foreground (gdk->fill_gc, gdk->fill_pixel);
        }
    }

    /* Now the crazy part */

    /* Free existing GdkPoint array */

    if (gdk->points) {
        g_free (gdk->points);
        gdk->points = NULL;
        gdk->len_points = 0;
        gdk->num_points = 0;
    }

    /* Free subpath lists */

    while (gdk->closed_paths) gdk->closed_paths = g_slist_remove (gdk->closed_paths, gdk->closed_paths->data);
    while (gdk->open_paths) gdk->open_paths = g_slist_remove (gdk->open_paths, gdk->open_paths->data);

    /* Calcualte new GdkPoints array and subpath lists */

    if (priv->path) {
        GnomeCanvasPathDef * apath, * cpath, * opath;
        ArtBpath * abpath;
        GSList * clist, * olist;
        gint pos;

#if 0
        /* Allocate array */
        gdk->num_points = gnome_canvas_path_def_length (priv->path) * 1000 - 1;
        gdk->points = g_new (GdkPoint, gdk->num_points);
        g_print ("Points %d\n", gdk->num_points);
        /* Transform path */
#endif

        abpath = art_bpath_affine_transform (gnome_canvas_path_def_bpath (priv->path), affine);
        apath = gnome_canvas_path_def_new_from_bpath (abpath);

        /* Split path into open and closed parts */

        cpath = gnome_canvas_path_def_closed_parts (apath);
        opath = gnome_canvas_path_def_open_parts (apath);
        gnome_canvas_path_def_unref (apath);

        /* Split partial paths into subpaths */

        clist = gnome_canvas_path_def_split (cpath);
        gnome_canvas_path_def_unref (cpath);
        olist = gnome_canvas_path_def_split (opath);
        gnome_canvas_path_def_unref (opath);

        pos = 0;

        /* Fill GdkPoints and add subpaths to list: closed subpaths */

        while (clist) {
            GnomeCanvasPathDef * path;
            ArtBpath * bpath;
            ArtVpath * vpath;
            gint len, i;

            path = (GnomeCanvasPathDef *) clist->data;
            bpath = gnome_canvas_path_def_bpath (path);
            vpath = art_bez_path_to_vec (bpath, 0.1);
            for (len = 0; vpath[len].code != ART_END; len++);

            gnome_canvas_shape_ensure_gdk_points (gdk, len);
            for (i = 0; i < len; i++) {
                gdk->points[pos + i].x = (gint) floor (vpath[i].x + 0.5);
                gdk->points[pos + i].y = (gint) floor (vpath[i].y + 0.5);

                if (bbox_set) {
                    x1 = MIN (x1, gdk->points[pos + i].x);
                    x2 = MAX (x2, gdk->points[pos + i].x);
                    y1 = MIN (y1, gdk->points[pos + i].y);
                    y2 = MAX (y2, gdk->points[pos + i].y);
                } else {
                    bbox_set = TRUE;
                    x1 = x2 = gdk->points[pos + i].x;
                    y1 = y2 = gdk->points[pos + i].y;
                }
            }
            gdk->num_points += len;

            art_free (vpath);

            if (len > 0) {
                pos += len;
                gdk->closed_paths = g_slist_append (gdk->closed_paths, GINT_TO_POINTER (len));
            }

            gnome_canvas_path_def_unref (path);
            clist = g_slist_remove (clist, clist->data);
        }

        /* Fill GdkPoints and add subpaths to list: open subpaths */

        while (olist) {
            GnomeCanvasPathDef * path;
            ArtBpath * bpath;
            ArtVpath * vpath;
            gint len, i;

            path = (GnomeCanvasPathDef *) olist->data;
            bpath = gnome_canvas_path_def_bpath (path);
            vpath = art_bez_path_to_vec (bpath, 0.1);
            for (len = 0; vpath[len].code != ART_END; len++);

            gnome_canvas_shape_ensure_gdk_points (gdk, len);
            for (i = 0; i < len; i++) {
                gdk->points[pos + i].x = (gint) floor (vpath[i].x + 0.5);
                gdk->points[pos + i].y = (gint) floor (vpath[i].y + 0.5);

                if (bbox_set) {
                    x1 = MIN (x1, gdk->points[pos + i].x);
                    x2 = MAX (x2, gdk->points[pos + i].x);
                    y1 = MIN (y1, gdk->points[pos + i].y);
                    y2 = MAX (y2, gdk->points[pos + i].y);
                } else {
                    bbox_set = TRUE;
                    x1 = x2 = gdk->points[pos + i].x;
                    y1 = y2 = gdk->points[pos + i].y;
                }
            }
            gdk->num_points += len;

            art_free (vpath);

            if (len > 0) {
                pos += len;
                gdk->open_paths = g_slist_append (gdk->open_paths, GINT_TO_POINTER (len));
            }

            gnome_canvas_path_def_unref (path);
            olist = g_slist_remove (olist, olist->data);
        }

    }

    if (bbox_set) {
        if (priv->outline_set) {
            gint stroke_border = (priv->join == GDK_JOIN_MITER)
                ? ceil (10.43*width/2) /* 10.43 is the miter limit for X11 */
                : ceil (width/2);
            x1 -= stroke_border;
            x2 += stroke_border;
            y1 -= stroke_border;
            y2 += stroke_border;
        }

        gnome_canvas_update_bbox (GNOME_CANVAS_ITEM (shape),
                      x1, y1,
                      x2 + 1, y2 + 1);
    }

}

static void
gnome_canvas_shape_update (GnomeCanvasItem *item, gdouble *affine, ArtSVP *clip_path, gint flags)
{
    GnomeCanvasShape * shape;
    GnomeCanvasShapePriv * priv;
    ArtSVP * svp;

    shape = GNOME_CANVAS_SHAPE (item);

    priv = shape->priv;

    /* Common part */
    if (GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->update) {
        GNOME_CANVAS_ITEM_CLASS (gnome_canvas_shape_parent_class)->update (item, affine, clip_path, flags);
    }

    /* Outline width */
    shape->priv->scale = art_affine_expansion (affine);

    /* Clipped fill SVP */

    if ((priv->fill_set) && (priv->path) && (gnome_canvas_path_def_any_closed (priv->path))) {
        GnomeCanvasPathDef * cpath;
        ArtSvpWriter *swr;
        ArtVpath *vpath;
        ArtBpath *abp;
        ArtSVP *svp2;

        /* Get closed part of path */

        cpath = gnome_canvas_path_def_closed_parts (shape->priv->path);
        abp = art_bpath_affine_transform (gnome_canvas_path_def_bpath (cpath), affine);
        gnome_canvas_path_def_unref (cpath);

        /* Render, until SVP */

        vpath = art_bez_path_to_vec (abp, 0.1);
        art_free (abp);

        svp = art_svp_from_vpath (vpath);
        art_free (vpath);

        swr = art_svp_writer_rewind_new (shape->priv->wind);
        art_svp_intersector (svp, swr);

        svp2 = art_svp_writer_rewind_reap (swr);
        art_svp_free (svp);

                if (priv->fill_svp) {
                        art_svp_free (priv->fill_svp);
                        priv->fill_svp = NULL;
                }
                /* No clipping */
                shape->priv->fill_svp = svp2;
    }

    if (priv->outline_set && priv->path && !gnome_canvas_path_def_is_empty (priv->path)) {
        gdouble width;
        ArtBpath * abp;
        ArtVpath * vpath;

        /* Set linewidth */

        if (priv->width_pixels) {
            width = priv->width;
        } else {
            width = priv->width * priv->scale;
        }

        if (width < 0.5) width = 0.5;

        /* Render full path until vpath */

        abp = art_bpath_affine_transform (gnome_canvas_path_def_bpath (priv->path), affine);

        vpath = art_bez_path_to_vec (abp, 0.1);
        art_free (abp);

        /* If dashed, apply dash */

        if (priv->dash.dash != NULL)
        {
            ArtVpath *old = vpath;

            vpath = art_vpath_dash (old, &priv->dash);
            art_free (old);
        }

        /* Stroke vpath to SVP */

        svp = art_svp_vpath_stroke (vpath,
                        gnome_canvas_join_gdk_to_art (priv->join),
                        gnome_canvas_cap_gdk_to_art (priv->cap),
                        width,
                        priv->miterlimit,
                        0.25);
        art_free (vpath);

                if (priv->outline_svp) {
                        art_svp_free (priv->outline_svp);
                        priv->outline_svp = NULL;
                }
                /* No clipping (yet) */
                shape->priv->outline_svp = svp;
    }

    /* Gdk requires additional handling */
        gnome_canvas_shape_update_gdk (shape, affine, clip_path, flags);
}

static GnomeCanvasItem *
gnome_canvas_shape_point (GnomeCanvasItem *item, gdouble x, gdouble y,
                gint cx, gint cy)
{
    GnomeCanvasShape *shape;
    gint wind;

#if 0
    /* fixme: This is just for debugging, canvas should ensure that */
    /* fixme: IF YOU ARE SURE THAT IT IS CORRECT BEHAVIOUR, you can remove warning */
    /* fixme: and make it to return silently */
    g_return_val_if_fail (!item->canvas->need_update, 1e18);
#endif

    shape = GNOME_CANVAS_SHAPE (item);

    /* todo: update? */
    if (shape->priv->fill_set && shape->priv->fill_svp) {
        wind = art_svp_point_wind (shape->priv->fill_svp, cx, cy);
        if ((shape->priv->wind == ART_WIND_RULE_NONZERO) && (wind != 0))
            return item;
        if ((shape->priv->wind == ART_WIND_RULE_ODDEVEN) && ((wind & 0x1) != 0))
                return item;
    }

    if (shape->priv->outline_set && shape->priv->outline_svp) {
        wind = art_svp_point_wind (shape->priv->outline_svp, cx, cy);
        if (wind)
                        return item;
    }

    return NULL;
}

/* Helpers */

/* Get 32bit rgba color from GdkColor */

static guint32
get_rgba_from_color (GdkColor * color)
{
    return ((color->red & 0xff00) << 16) | ((color->green & 0xff00) << 8) | (color->blue & 0xff00) | 0xff;
}

/* Get Gdk pixel value from 32bit rgba color */

static gulong
get_pixel_from_rgba (GnomeCanvasItem *item, guint32 rgba_color)
{
    return gnome_canvas_get_color_pixel (item->canvas, rgba_color);
}

/* Convenience function to set a GC's foreground color to the specified pixel value */

static void
set_gc_foreground (GdkGC *gc, gulong pixel)
{
    GdkColor c;

    g_assert (gc != NULL);

    c.pixel = pixel;

    gdk_gc_set_foreground (gc, &c);
}

/* Creates private Gdk struct, if not present */
/* We cannot do it during ::init, as we have to know canvas */

static void
gcbp_ensure_gdk (GnomeCanvasShape * shape)
{
    if (!shape->priv->gdk) {
        GnomeCanvasShapePrivGdk * gdk;

        gdk = g_new (GnomeCanvasShapePrivGdk, 1);

        gdk->fill_pixel = get_pixel_from_rgba ((GnomeCanvasItem *) shape, shape->priv->fill_rgba);
        gdk->outline_pixel = get_pixel_from_rgba ((GnomeCanvasItem *) shape, shape->priv->outline_rgba);

        gdk->fill_gc = NULL;
        gdk->outline_gc = NULL;

        gdk->len_points = 0;
        gdk->num_points = 0;
        gdk->points = NULL;
        gdk->closed_paths = NULL;
        gdk->open_paths = NULL;

        gdk->ctx = NULL;

        shape->priv->gdk = gdk;
    }
}

/* Destroy private Gdk struct */
/* It is here, to make ::destroy implementation shorter :) */

static void
gcbp_destroy_gdk (GnomeCanvasShape * shape)
{
    GnomeCanvasShapePrivGdk * gdk;

    gdk = shape->priv->gdk;

    if (gdk) {
        g_assert (!gdk->fill_gc);
        g_assert (!gdk->outline_gc);

        if (gdk->points)
            g_free (gdk->points);

        while (gdk->closed_paths)
            gdk->closed_paths = g_slist_remove (gdk->closed_paths, gdk->closed_paths->data);
        while (gdk->open_paths)
            gdk->open_paths = g_slist_remove (gdk->open_paths, gdk->open_paths->data);

        if (gdk->ctx)
            gcbp_draw_ctx_unref (gdk->ctx);

        g_free (gdk);

        shape->priv->gdk = NULL;
    }
}

/*
 * Ensure, that per-canvas Ctx struct is present and bitmaps are
 * big enough, to mask full redraw area. Ctx is refcounted and
 * defined as "BpathDrawCtx" data member on parent canvas
 */

static void
gcbp_ensure_mask (GnomeCanvasShape * shape, gint width, gint height)
{
    GnomeCanvasShapePrivGdk * gdk;
    GCBPDrawCtx * ctx;

    gdk = shape->priv->gdk;
    g_assert (gdk != NULL);
    ctx = gdk->ctx;

    if (!ctx) {
        /* Ctx is not yet defined for us */

        GnomeCanvas * canvas;

        canvas = GNOME_CANVAS_ITEM (shape)->canvas;

        ctx = g_object_get_data (G_OBJECT (canvas), "BpathDrawCtx");

        if (!ctx) {
            /* Ctx is not defined for parent canvas yet */

            ctx = g_new (GCBPDrawCtx, 1);

            ctx->refcount = 1;
            ctx->canvas = canvas;
            ctx->width = 0;
            ctx->height = 0;

            ctx->mask = NULL;
            ctx->clip = NULL;

            ctx->clear_gc = NULL;
            ctx->xor_gc = NULL;

            g_object_set_data (G_OBJECT (canvas), "BpathDrawCtx", ctx);

        } else {
            ctx->refcount++;
        }

        gdk->ctx = ctx;

    }

    /* Now we are sure, that ctx is present and properly refcounted */

    if ((width > ctx->width) || (height > ctx->height)) {
        /* Ctx is too small */
        GtkWidget *widget;
        GdkWindow * window;

        widget = GTK_WIDGET (GNOME_CANVAS_ITEM (shape)->canvas);
        window = gtk_widget_get_window (widget);

        if (ctx->clear_gc) g_object_unref (ctx->clear_gc);
        if (ctx->xor_gc) g_object_unref (ctx->xor_gc);
        if (ctx->mask) g_object_unref (ctx->mask);
        if (ctx->clip) g_object_unref (ctx->clip);

        ctx->mask = gdk_pixmap_new (window, width, height, 1);
        ctx->clip = NULL;

        ctx->clear_gc = gdk_gc_new (ctx->mask);
        gdk_gc_set_function (ctx->clear_gc, GDK_CLEAR);

        ctx->xor_gc = gdk_gc_new (ctx->mask);
        gdk_gc_set_function (ctx->xor_gc, GDK_INVERT);
    }
}

/* It is cleaner to have it here, not in parent function */

static void
gcbp_draw_ctx_unref (GCBPDrawCtx * ctx)
{
    if (--ctx->refcount < 1) {
        if (ctx->clear_gc)
            g_object_unref (ctx->clear_gc);
        if (ctx->xor_gc)
            g_object_unref (ctx->xor_gc);

        if (ctx->mask)
            g_object_unref (ctx->mask);
        if (ctx->clip)
            g_object_unref (ctx->clip);

        g_object_set_data (G_OBJECT (ctx->canvas), "BpathDrawCtx", NULL);
        g_free (ctx);
    }
}

static void
gnome_canvas_shape_bounds (GnomeCanvasItem *item, gdouble *x1, gdouble *y1, gdouble *x2, gdouble *y2)
{
    GnomeCanvasShape * shape;
    GnomeCanvasShapePriv * priv;
    ArtDRect bbox;
    ArtSVP * svp;

    shape = GNOME_CANVAS_SHAPE (item);

    priv = shape->priv;

    bbox.x0 = *x1;
    bbox.y0 = *y1;
    bbox.x1 = *x2;
    bbox.y1 = *y2;

    if (priv->outline_set && priv->path && !gnome_canvas_path_def_is_empty (priv->path)) {
        gdouble width;
        ArtVpath * vpath;

        /* Set linewidth */

        if (priv->width_pixels) {
            width = priv->width;
        } else {
            width = priv->width * priv->scale;
        }

        if (width < 0.5) width = 0.5;

        /* Render full path until vpath */

        vpath = art_bez_path_to_vec (gnome_canvas_path_def_bpath (priv->path), 0.1);

        /* If dashed, apply dash */

        if (priv->dash.dash != NULL)
        {
            ArtVpath *old = vpath;

            vpath = art_vpath_dash (old, &priv->dash);
            art_free (old);
        }

        /* Stroke vpath to SVP */

        svp = art_svp_vpath_stroke (vpath,
                        gnome_canvas_join_gdk_to_art (priv->join),
                        gnome_canvas_cap_gdk_to_art (priv->cap),
                        width,
                        priv->miterlimit,
                        0.25);
        art_free (vpath);
        art_drect_svp (&bbox, svp);
        art_svp_free (svp);
    } else if ((priv->fill_set) && (priv->path) && (gnome_canvas_path_def_any_closed (priv->path))) {
        GnomeCanvasPathDef *cpath;
        ArtSvpWriter *swr;
        ArtVpath *vpath;
        ArtSVP *svp2;

        /* Get closed part of path */
        cpath = gnome_canvas_path_def_closed_parts (shape->priv->path);
        /* Render, until SVP */
        vpath = art_bez_path_to_vec (gnome_canvas_path_def_bpath (cpath), 0.1);
        gnome_canvas_path_def_unref (cpath);

        svp = art_svp_from_vpath (vpath);
        art_free (vpath);

        swr = art_svp_writer_rewind_new (shape->priv->wind);
        art_svp_intersector (svp, swr);

        svp2 = art_svp_writer_rewind_reap (swr);
        art_svp_free (svp);

        art_drect_svp (&bbox, svp2);
        art_svp_free (svp2);
    }

    *x1 = bbox.x0;
    *y1 = bbox.y0;
    *x2 = bbox.x1;
    *y2 = bbox.y1;
}