static void sp_canvas_bpath_update(SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags)
{
    SPCanvasBPath *cbp = SP_CANVAS_BPATH(item);

    item->canvas->requestRedraw((int)item->x1, (int)item->y1, (int)item->x2, (int)item->y2);

    if (reinterpret_cast<SPCanvasItemClass *>(sp_canvas_bpath_parent_class)->update) {
        reinterpret_cast<SPCanvasItemClass *>(sp_canvas_bpath_parent_class)->update(item, affine, flags);
    }

    sp_canvas_item_reset_bounds (item);

    if (!cbp->curve) return;

    cbp->affine = affine;

    Geom::OptRect bbox = bounds_exact_transformed(cbp->curve->get_pathvector(), affine);

    if (bbox) {
        item->x1 = (int)bbox->min()[Geom::X] - 1;
        item->y1 = (int)bbox->min()[Geom::Y] - 1;
        item->x2 = (int)bbox->max()[Geom::X] + 1;
        item->y2 = (int)bbox->max()[Geom::Y] + 1;
    } else {
        item->x1 = 0;
        item->y1 = 0;
        item->x2 = 0;
        item->y2 = 0;
    }
    item->canvas->requestRedraw((int)item->x1, (int)item->y1, (int)item->x2, (int)item->y2);
}

Geom::OptRect SPTRef::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
    Geom::OptRect bbox;
    // find out the ancestor text which holds our layout
    SPObject const *parent_text = this;

    while ( parent_text && !SP_IS_TEXT(parent_text) ) {
        parent_text = parent_text->parent;
    }

    if (parent_text == NULL) {
        return bbox;
    }

    // get the bbox of our portion of the layout
    bbox = SP_TEXT(parent_text)->layout.bounds(transform,
        sp_text_get_length_upto(parent_text, this), sp_text_get_length_upto(this, NULL) - 1);

    // Add stroke width
    // FIXME this code is incorrect
    if (bbox && type == SPItem::VISUAL_BBOX && !this->style->stroke.isNone()) {
        double scale = transform.descrim();
        bbox->expandBy(0.5 * this->style->stroke_width.computed * scale);
    }

    return bbox;
}

Geom::Point SPAvoidRef::getConnectionPointPos()
{
    g_assert(item);
    // the center is all we are interested in now; we used to care
    // about non-center points, but that's moot.
    Geom::OptRect bbox = item->documentVisualBounds();
    return (bbox) ? bbox->midpoint() : Geom::Point(0, 0);
}

Geom::OptRect Selection::visualBounds() const
{
    std::vector<SPItem*> const items = const_cast<Selection *>(this)->itemList();

    Geom::OptRect bbox;
    for ( std::vector<SPItem*>::const_iterator iter=items.begin();iter!=items.end(); ++iter) {
        bbox.unionWith(SP_ITEM(*iter)->desktopVisualBounds());
    }
    return bbox;
}

Geom::OptRect SPFlowtext::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
    Geom::OptRect bbox = this->layout.bounds(transform);

    // Add stroke width
    // FIXME this code is incorrect
    if (bbox && type == SPItem::VISUAL_BBOX && !this->style->stroke.isNone()) {
        double scale = transform.descrim();
        bbox->expandBy(0.5 * this->style->stroke_width.computed * scale);
    }

    return bbox;
}

Geom::OptRect SPClipPath::geometricBounds(Geom::Affine const &transform) {
    Geom::OptRect bbox;

    for (SPObject *i = firstChild(); i; i = i->getNext()) {
        if (SP_IS_ITEM(i)) {
        	Geom::OptRect tmp = SP_ITEM(i)->geometricBounds(Geom::Affine(SP_ITEM(i)->transform) * transform);
			bbox.unionWith(tmp);
        }
    }

    return bbox;
}

// If we have a selection of multiple items, then the center of the first item
// will be returned; this is also the case in SelTrans::centerRequest()
boost::optional<Geom::Point> Selection::center() const {
    std::vector<SPItem*> const items = const_cast<Selection *>(this)->itemList();
    if (!items.empty()) {
        SPItem *first = items.back(); // from the first item in selection
        if (first->isCenterSet()) { // only if set explicitly
            return first->getCenter();
        }
    }
    Geom::OptRect bbox = preferredBounds();
    if (bbox) {
        return bbox->midpoint();
    } else {
        return boost::optional<Geom::Point>();
    }
}

static void
sp_selection_layout_widget_update(SPWidget *spw, Inkscape::Selection *sel)
{
    if (g_object_get_data(G_OBJECT(spw), "update")) {
        return;
    }

    g_object_set_data(G_OBJECT(spw), "update", GINT_TO_POINTER(TRUE));

    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
    using Geom::X;
    using Geom::Y;
    if ( sel && !sel->isEmpty() ) {
        int prefs_bbox = prefs->getInt("/tools/bounding_box", 0);
        SPItem::BBoxType bbox_type = (prefs_bbox ==0)?
            SPItem::VISUAL_BBOX : SPItem::GEOMETRIC_BBOX;
        Geom::OptRect const bbox(sel->bounds(bbox_type));
        if ( bbox ) {
            UnitTracker *tracker = reinterpret_cast<UnitTracker*>(g_object_get_data(G_OBJECT(spw), "tracker"));
            Unit const *unit = tracker->getActiveUnit();
            g_return_if_fail(unit != NULL);

            struct { char const *key; double val; } const keyval[] = {
                { "X", bbox->min()[X] },
                { "Y", bbox->min()[Y] },
                { "width", bbox->dimensions()[X] },
                { "height", bbox->dimensions()[Y] }
            };

            if (unit->type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) {
                double const val = unit->factor * 100;
                for (unsigned i = 0; i < G_N_ELEMENTS(keyval); ++i) {
                    GtkAdjustment *a = GTK_ADJUSTMENT(g_object_get_data(G_OBJECT(spw), keyval[i].key));
                    gtk_adjustment_set_value(a, val);
                    tracker->setFullVal( a, keyval[i].val );
                }
            } else {
                for (unsigned i = 0; i < G_N_ELEMENTS(keyval); ++i) {
                    GtkAdjustment *a = GTK_ADJUSTMENT(g_object_get_data(G_OBJECT(spw), keyval[i].key));
                    gtk_adjustment_set_value(a, Quantity::convert(keyval[i].val, "px", unit));
                }
            }
        }
    }

    g_object_set_data(G_OBJECT(spw), "update", GINT_TO_POINTER(FALSE));
}

/**
Center of bbox of item
*/
static Geom::Point
unclump_center (SPItem *item)
{
    std::map<const gchar *, Geom::Point>::iterator i = c_cache.find(item->getId());
    if ( i != c_cache.end() ) {
        return i->second;
    }

    Geom::OptRect r = item->desktopVisualBounds();
    if (r) {
        Geom::Point const c = r->midpoint();
        c_cache[item->getId()] = c;
        return c;
    } else {
        // FIXME
        return Geom::Point(0, 0);
    }
}

static Geom::Point
unclump_wh (SPItem *item)
{
    Geom::Point wh;
    std::map<const gchar *, Geom::Point>::iterator i = wh_cache.find(item->getId());
    if ( i != wh_cache.end() ) {
        wh = i->second;
    } else {
        Geom::OptRect r = item->desktopVisualBounds();
        if (r) {
            wh = r->dimensions();
            wh_cache[item->getId()] = wh;
        } else {
            wh = Geom::Point(0, 0);
        }
    }

    return wh;
}

SPItem *Selection::_sizeistItem(bool sml, Selection::CompareSize compare) {
    std::vector<SPItem*> const items = const_cast<Selection *>(this)->itemList();
    gdouble max = sml ? 1e18 : 0;
    SPItem *ist = NULL;

    for ( std::vector<SPItem*>::const_iterator i=items.begin();i!=items.end(); ++i) {
        Geom::OptRect obox = SP_ITEM(*i)->desktopPreferredBounds();
        if (!obox || obox.isEmpty()) continue;
        Geom::Rect bbox = *obox;

        gdouble size = compare == 2 ? bbox.area() :
            (compare == 1 ? bbox.width() : bbox.height());
        size = sml ? size : size * -1;
        if (size < max) {
            max = size;
            ist = SP_ITEM(*i);
        }
    }
    return ist;
}

void sp_textpath_to_text(SPObject *tp)
{
    SPObject *text = tp->parent;

    Geom::OptRect bbox = SP_ITEM(text)->geometricBounds(SP_ITEM(text)->i2doc_affine());

    if (!bbox) {
    	return;
    }

    Geom::Point xy = bbox->min();
    xy *= tp->document->getDocumentScale().inverse(); // Convert to user-units.
    
    // make a list of textpath children
    GSList *tp_reprs = NULL;

    for (SPObject *o = tp->firstChild() ; o != NULL; o = o->next) {
        tp_reprs = g_slist_prepend(tp_reprs, o->getRepr());
    }

    for ( GSList *i = tp_reprs ; i ; i = i->next ) {
        // make a copy of each textpath child
        Inkscape::XML::Node *copy = ((Inkscape::XML::Node *) i->data)->duplicate(text->getRepr()->document());
        // remove the old repr from under textpath
        tp->getRepr()->removeChild((Inkscape::XML::Node *) i->data);
        // put its copy under text
        text->getRepr()->addChild(copy, NULL); // fixme: copy id
    }

    //remove textpath
    tp->deleteObject();
    g_slist_free(tp_reprs);

    // set x/y on text (to be near where it was when on path)
    /* fixme: Yuck, is this really the right test? */
    if (xy[Geom::X] != 1e18 && xy[Geom::Y] != 1e18) {
        sp_repr_set_svg_double(text->getRepr(), "x", xy[Geom::X]);
        sp_repr_set_svg_double(text->getRepr(), "y", xy[Geom::Y]);
    }
}

void Inkscape::getBBoxPoints(Geom::OptRect const bbox,
                             std::vector<SnapCandidatePoint> *points,
                             bool const /*isTarget*/,
                             bool const includeCorners,
                             bool const includeLineMidpoints,
                             bool const includeObjectMidpoints)
{
    if (bbox) {
        // collect the corners of the bounding box
        for ( unsigned k = 0 ; k < 4 ; k++ ) {
            if (includeCorners) {
                points->push_back(SnapCandidatePoint(bbox->corner(k), SNAPSOURCE_BBOX_CORNER, -1, SNAPTARGET_BBOX_CORNER, *bbox));
            }
            // optionally, collect the midpoints of the bounding box's edges too
            if (includeLineMidpoints) {
                points->push_back(SnapCandidatePoint((bbox->corner(k) + bbox->corner((k+1) % 4))/2, SNAPSOURCE_BBOX_EDGE_MIDPOINT, -1, SNAPTARGET_BBOX_EDGE_MIDPOINT, *bbox));
            }
        }
        if (includeObjectMidpoints) {
            points->push_back(SnapCandidatePoint(bbox->midpoint(), SNAPSOURCE_BBOX_MIDPOINT, -1, SNAPTARGET_BBOX_MIDPOINT, *bbox));
        }
    }
}

void
sp_gradient_pattern_common_setup(cairo_pattern_t *cp,
                                 SPGradient *gr,
                                 Geom::OptRect const &bbox,
                                 double opacity)
{
    // set spread type
    switch (gr->getSpread()) {
    case SP_GRADIENT_SPREAD_REFLECT:
        cairo_pattern_set_extend(cp, CAIRO_EXTEND_REFLECT);
        break;
    case SP_GRADIENT_SPREAD_REPEAT:
        cairo_pattern_set_extend(cp, CAIRO_EXTEND_REPEAT);
        break;
    case SP_GRADIENT_SPREAD_PAD:
    default:
        cairo_pattern_set_extend(cp, CAIRO_EXTEND_PAD);
        break;
    }

    // add stops
    for (std::vector<SPGradientStop>::iterator i = gr->vector.stops.begin();
         i != gr->vector.stops.end(); ++i)
    {
        // multiply stop opacity by paint opacity
        cairo_pattern_add_color_stop_rgba(cp, i->offset,
            i->color.v.c[0], i->color.v.c[1], i->color.v.c[2], i->opacity * opacity);
    }

    // set pattern matrix
    Geom::Affine gs2user = gr->gradientTransform;
    if (gr->getUnits() == SP_GRADIENT_UNITS_OBJECTBOUNDINGBOX && bbox) {
        Geom::Affine bbox2user(bbox->width(), 0, 0, bbox->height(), bbox->left(), bbox->top());
        gs2user *= bbox2user;
    }
    ink_cairo_pattern_set_matrix(cp, gs2user.inverse());
}

/** Feeds path-creating calls to the cairo context translating them from the Path, with the given transform and shift */
static void
feed_path_to_cairo (cairo_t *ct, Geom::Path const &path, Geom::Affine trans, Geom::OptRect area, bool optimize_stroke, double stroke_width)
{
    if (!area)
        return;
    if (path.empty())
        return;

    // Transform all coordinates to coords within "area"
    Geom::Point shift = area->min();
    Geom::Rect view = *area;
    view.expandBy (stroke_width);
    view = view * (Geom::Affine)Geom::Translate(-shift);
    //  Pass transformation to feed_curve, so that we don't need to create a whole new path.
    Geom::Affine transshift(trans * Geom::Translate(-shift));

    Geom::Point initial = path.initialPoint() * transshift;
    cairo_move_to(ct, initial[0], initial[1] );

    for(Geom::Path::const_iterator cit = path.begin(); cit != path.end_open(); ++cit) {
        feed_curve_to_cairo(ct, *cit, transshift, view, optimize_stroke);
    }

    if (path.closed()) {
        if (!optimize_stroke) {
            cairo_close_path(ct);
        } else {
            cairo_line_to(ct, initial[0], initial[1]);
            /* We cannot use cairo_close_path(ct) here because some parts of the path may have been
               clipped and not drawn (maybe the before last segment was outside view area), which 
               would result in closing the "subpath" after the last interruption, not the entire path.

               However, according to cairo documentation:
               The behavior of cairo_close_path() is distinct from simply calling cairo_line_to() with the equivalent coordinate
               in the case of stroking. When a closed sub-path is stroked, there are no caps on the ends of the sub-path. Instead,
               there is a line join connecting the final and initial segments of the sub-path. 

               The correct fix will be possible when cairo introduces methods for moving without
               ending/starting subpaths, which we will use for skipping invisible segments; then we
               will be able to use cairo_close_path here. This issue also affects ps/eps/pdf export,
               see bug 168129
            */
        }
    }
}

unsigned DrawingGlyphs::_updateItem(Geom::IntRect const &/*area*/, UpdateContext const &ctx, unsigned /*flags*/, unsigned /*reset*/)
{
    DrawingText *ggroup = dynamic_cast<DrawingText *>(_parent);
    if (!ggroup) {
        throw InvalidItemException();
    }

    if (!_font || !ggroup->_style) {
        return STATE_ALL;
    }

    _pick_bbox = Geom::IntRect();
    _bbox = Geom::IntRect();

    Geom::OptRect b = bounds_exact_transformed(*_font->PathVector(_glyph), ctx.ctm);
    if (b && (ggroup->_nrstyle.stroke.type != NRStyle::PAINT_NONE)) {
        float width, scale;
        scale = ctx.ctm.descrim();
        if (_transform) {
            scale /= _transform->descrim(); // FIXME temporary hack
        }
        width = MAX(0.125, ggroup->_nrstyle.stroke_width * scale);
        if ( fabs(ggroup->_nrstyle.stroke_width * scale) > 0.01 ) { // FIXME: this is always true
            b->expandBy(0.5 * width);
        }
        // save bbox without miters for picking
        _pick_bbox = b->roundOutwards();

        float miterMax = width * ggroup->_nrstyle.miter_limit;
        if ( miterMax > 0.01 ) {
            // grunt mode. we should compute the various miters instead
            // (one for each point on the curve)
            b->expandBy(miterMax);
        }
        _bbox = b->roundOutwards();
    } else if (b) {
        _bbox = b->roundOutwards();
        _pick_bbox = *_bbox;
    }

    return STATE_ALL;
}

/**
 * Update derived data before operations.
 * The purpose of this call is to recompute internal data which depends
 * on the attributes of the object, but is not directly settable by the user.
 * Precomputing this data speeds up later rendering, because some items
 * can be omitted.
 *
 * Currently this method handles updating the visual and geometric bounding boxes
 * in pixels, storing the total transformation from item space to the screen
 * and cache invalidation.
 *
 * @param area Area to which the update should be restricted. Only takes effect
 *             if the bounding box is known.
 * @param ctx A structure to store cascading state.
 * @param flags Which internal data should be recomputed. This can be any combination
 *              of StateFlags.
 * @param reset State fields that should be reset before processing them. This is
 *              a means to force a recomputation of internal data even if the item
 *              considers it up to date. Mainly for internal use, such as
 *              propagating bounding box recomputation to children when the item's
 *              transform changes.
 */
void
DrawingItem::update(Geom::IntRect const &area, UpdateContext const &ctx, unsigned flags, unsigned reset)
{
    bool render_filters = _drawing.renderFilters();
    bool outline = _drawing.outline();

    // Set reset flags according to propagation status
    reset |= _propagate_state;
    _propagate_state = 0;

    _state &= ~reset; // reset state of this item

    if ((~_state & flags) == 0) return;  // nothing to do

    // TODO this might be wrong
    if (_state & STATE_BBOX) {
        // we have up-to-date bbox
        if (!area.intersects(outline ? _bbox : _drawbox)) return;
    }

    // compute which elements need an update
    unsigned to_update = _state ^ flags;

    // this needs to be called before we recurse into children
    if (to_update & STATE_BACKGROUND) {
        _background_accumulate = _background_new;
        if (_child_type == CHILD_NORMAL && _parent->_background_accumulate)
            _background_accumulate = true;
    }

    UpdateContext child_ctx(ctx);
    if (_transform) {
        child_ctx.ctm = *_transform * ctx.ctm;
    }
    /* Remember the transformation matrix */
    Geom::Affine ctm_change = _ctm.inverse() * child_ctx.ctm;
    _ctm = child_ctx.ctm;

    // update _bbox and call this function for children
    _state = _updateItem(area, child_ctx, flags, reset);

    if (to_update & STATE_BBOX) {
        // compute drawbox
        if (_filter && render_filters) {
            Geom::OptRect enlarged = _filter->filter_effect_area(_item_bbox);
            if (enlarged) {
                *enlarged *= ctm();
                _drawbox = enlarged->roundOutwards();
            } else {
                _drawbox = Geom::OptIntRect();
            }
        } else {
            _drawbox = _bbox;
        }

        // Clipping
        if (_clip) {
            _clip->update(area, child_ctx, flags, reset);
            if (outline) {
                _bbox.unionWith(_clip->_bbox);
            } else {
                _drawbox.intersectWith(_clip->_bbox);
            }
        }
        // Masking
        if (_mask) {
            _mask->update(area, child_ctx, flags, reset);
            if (outline) {
                _bbox.unionWith(_mask->_bbox);
            } else {
                // for masking, we need full drawbox of mask
                _drawbox.intersectWith(_mask->_drawbox);
            }
        }
    }

    if (to_update & STATE_CACHE) {
        // Update cache score for this item
//.........这里部分代码省略.........

/**
* Takes a list of inkscape items, extracts the graph defined by
* connectors between them, and uses graph layout techniques to find
* a nice layout
*/
void graphlayout(std::vector<SPItem*> const &items) {
    if(items.empty()) {
        return;
    }

    list<SPItem *> selected;
    filterConnectors(items,selected);
    if (selected.empty()) return;

    const unsigned n=selected.size();
    //Check 2 or more selected objects
    if (n < 2) return;

    // add the connector spacing to the size of node bounding boxes
    // so that connectors can always be routed between shapes
    SPDesktop* desktop = SP_ACTIVE_DESKTOP;
    double spacing = 0;
    if(desktop) spacing = desktop->namedview->connector_spacing+0.1;

    map<string,unsigned> nodelookup;
    vector<Rectangle*> rs;
    vector<Edge> es;
    for (list<SPItem *>::iterator i(selected.begin());
         i != selected.end();
         ++i)
    {
        SPItem *u=*i;
        Geom::OptRect const item_box = u->desktopVisualBounds();
        if(item_box) {
            Geom::Point ll(item_box->min());
            Geom::Point ur(item_box->max());
            nodelookup[u->getId()]=rs.size();
            rs.push_back(new Rectangle(ll[0]-spacing,ur[0]+spacing,
                        ll[1]-spacing,ur[1]+spacing));
        } else {
            // I'm not actually sure if it's possible for something with a
            // NULL item-box to be attached to a connector in which case we
            // should never get to here... but if such a null box can occur it's
            // probably pretty safe to simply ignore
            //fprintf(stderr,"NULL item_box found in graphlayout, ignoring!\n");
        }
    }

    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
    SimpleConstraints scx,scy;
    double ideal_connector_length = prefs->getDouble("/tools/connector/length", 100.0);
    double directed_edge_height_modifier = 1.0;

    bool directed =       prefs->getBool("/tools/connector/directedlayout");
    bool avoid_overlaps = prefs->getBool("/tools/connector/avoidoverlaplayout");

    for (list<SPItem *>::iterator i(selected.begin());
         i != selected.end();
         ++i)
    {
        SPItem *iu=*i;
        map<string,unsigned>::iterator i_iter=nodelookup.find(iu->getId());
        map<string,unsigned>::iterator i_iter_end=nodelookup.end();
        if(i_iter==i_iter_end) {
            continue;
        }
        unsigned u=i_iter->second;
        std::vector<SPItem *> nlist=iu->avoidRef->getAttachedConnectors(Avoid::runningFrom);
        list<SPItem *> connectors;

        connectors.insert(connectors.end(), nlist.begin(), nlist.end());

        for (list<SPItem *>::iterator j(connectors.begin());
                j != connectors.end();
                ++j) {
            SPItem *conn=*j;
            SPItem *iv;
            SPItem *items[2];
            assert(isConnector(conn));
            SP_PATH(conn)->connEndPair.getAttachedItems(items);
            if(items[0]==iu) {
                iv=items[1];
            } else {
                iv=items[0];
            }

            if (iv == NULL) {
                // The connector is not attached to anything at the
                // other end so we should just ignore it.
                continue;
            }

            // If iv not in nodelookup we again treat the connector
            // as disconnected and continue
            map<string,unsigned>::iterator v_pair=nodelookup.find(iv->getId());
            if(v_pair!=nodelookup.end()) {
                unsigned v=v_pair->second;
                //cout << "Edge: (" << u <<","<<v<<")"<<endl;
                es.push_back(make_pair(u,v));
                if(conn->style->marker_end.set) {
//.........这里部分代码省略.........

void
ObjectCompositeSettings::_blendBlurValueChanged()
{
    if (!_subject) {
        return;
    }

    SPDesktop *desktop = _subject->getDesktop();
    if (!desktop) {
        return;
    }
    SPDocument *document = sp_desktop_document (desktop);

    if (_blocked)
        return;
    _blocked = true;

    // FIXME: fix for GTK breakage, see comment in SelectedStyle::on_opacity_changed; here it results in crash 1580903
    //sp_canvas_force_full_redraw_after_interruptions(sp_desktop_canvas(desktop), 0);

    Geom::OptRect bbox = _subject->getBounds(SPItem::GEOMETRIC_BBOX);
    double radius;
    if (bbox) {
        double perimeter = bbox->dimensions()[Geom::X] + bbox->dimensions()[Geom::Y];   // fixme: this is only half the perimeter, is that correct?
        radius = _fe_cb.get_blur_value() * perimeter / 400;
    } else {
        radius = 0;
    }

    const Glib::ustring blendmode = _fe_cb.get_blend_mode();

    //apply created filter to every selected item
    for (StyleSubject::iterator i = _subject->begin() ; i != _subject->end() ; ++i ) {
        if (!SP_IS_ITEM(*i)) {
            continue;
        }

        SPItem * item = SP_ITEM(*i);
        SPStyle *style = item->style;
        g_assert(style != NULL);

        if (blendmode != "normal") {
            SPFilter *filter = new_filter_simple_from_item(document, item, blendmode.c_str(), radius);
            sp_style_set_property_url(item, "filter", filter, false);
        } else {
            sp_style_set_property_url(item, "filter", NULL, false);
        }

        if (radius == 0 && item->style->filter.set
            && filter_is_single_gaussian_blur(SP_FILTER(item->style->getFilter()))) {
            remove_filter(item, false);
        }
        else if (radius != 0) {
            SPFilter *filter = modify_filter_gaussian_blur_from_item(document, item, radius);
            sp_style_set_property_url(item, "filter", filter, false);
        }

        //request update
        item->requestDisplayUpdate(( SP_OBJECT_MODIFIED_FLAG |
                                     SP_OBJECT_STYLE_MODIFIED_FLAG ));
    }

    DocumentUndo::maybeDone(document, _blur_tag.c_str(), _verb_code,
                            _("Change blur"));

    // resume interruptibility
    //sp_canvas_end_forced_full_redraws(sp_desktop_canvas(desktop));

    _blocked = false;
}

void
ObjectCompositeSettings::_subjectChanged() {
    if (!_subject) {
        return;
    }

    SPDesktop *desktop = _subject->getDesktop();
    if (!desktop) {
        return;
    }

    if (_blocked)
        return;
    _blocked = true;

    SPStyle *query = sp_style_new (sp_desktop_document(desktop));
    int result = _subject->queryStyle(query, QUERY_STYLE_PROPERTY_MASTEROPACITY);

    switch (result) {
        case QUERY_STYLE_NOTHING:
            _opacity_vbox.set_sensitive(false);
            // gtk_widget_set_sensitive (opa, FALSE);
            break;
        case QUERY_STYLE_SINGLE:
        case QUERY_STYLE_MULTIPLE_AVERAGED: // TODO: treat this slightly differently
        case QUERY_STYLE_MULTIPLE_SAME:
            _opacity_vbox.set_sensitive(true);
            _opacity_scale.get_adjustment()->set_value(100 * SP_SCALE24_TO_FLOAT(query->opacity.value));
            break;
    }

    //query now for current filter mode and average blurring of selection
    const int blend_result = _subject->queryStyle(query, QUERY_STYLE_PROPERTY_BLEND);
    switch(blend_result) {
        case QUERY_STYLE_NOTHING:
            _fe_cb.set_sensitive(false);
            break;
        case QUERY_STYLE_SINGLE:
        case QUERY_STYLE_MULTIPLE_SAME:
            _fe_cb.set_blend_mode(query->filter_blend_mode.value);
            _fe_cb.set_sensitive(true);
            break;
        case QUERY_STYLE_MULTIPLE_DIFFERENT:
            // TODO: set text
            _fe_cb.set_sensitive(false);
            break;
    }

    if(blend_result == QUERY_STYLE_SINGLE || blend_result == QUERY_STYLE_MULTIPLE_SAME) {
        int blur_result = _subject->queryStyle(query, QUERY_STYLE_PROPERTY_BLUR);
        switch (blur_result) {
            case QUERY_STYLE_NOTHING: //no blurring
                _fe_cb.set_blur_sensitive(false);
                break;
            case QUERY_STYLE_SINGLE:
            case QUERY_STYLE_MULTIPLE_AVERAGED:
            case QUERY_STYLE_MULTIPLE_SAME:
                Geom::OptRect bbox = _subject->getBounds(SPItem::GEOMETRIC_BBOX);
                if (bbox) {
                    double perimeter = bbox->dimensions()[Geom::X] + bbox->dimensions()[Geom::Y];   // fixme: this is only half the perimeter, is that correct?
                    _fe_cb.set_blur_sensitive(true);
                    //update blur widget value
                    float radius = query->filter_gaussianBlur_deviation.value;
                    float percent = radius * 400 / perimeter; // so that for a square, 100% == half side
                    _fe_cb.set_blur_value(percent);
                }
                break;
        }
    }

    sp_style_unref(query);

    _blocked = false;
}