Adding upstream version 1.3+ds.upstream/1.3+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 648 insertions, 0 deletions

diff --git a/src/distribution-snapper.cpp b/src/distribution-snapper.cpp
new file mode 100644
index 0000000..fadb521
--- /dev/null
+++ b/src/distribution-snapper.cpp
@@ -0,0 +1,648 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** \file
+ *  Snapping equidistant objects
+ *
+ * Authors:
+ *   Parth Pant <parthpant4@gmail.com>
+ *
+ * Copyright (C) 2021 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <2geom/circle.h>
+#include <2geom/line.h>
+#include <2geom/path-intersection.h>
+#include <2geom/path-sink.h>
+#include <memory>
+
+#include "desktop.h"
+#include "display/curve.h"
+#include "document.h"
+#include "inkscape.h"
+#include "live_effects/effect-enum.h"
+#include "object/sp-clippath.h"
+#include "object/sp-flowtext.h"
+#include "object/sp-image.h"
+#include "object/sp-item-group.h"
+#include "object/sp-mask.h"
+#include "object/sp-namedview.h"
+#include "object/sp-path.h"
+#include "object/sp-root.h"
+#include "object/sp-shape.h"
+#include "object/sp-text.h"
+#include "object/sp-use.h"
+#include "path/path-util.h" // curve_for_item
+#include "preferences.h"
+#include "style.h"
+#include "svg/svg.h"
+
+#define DISTRIBUTION_SNAPPING_EPSILON 0.5e-4f
+
+static bool compare_double(double x, double y, double epsilon = DISTRIBUTION_SNAPPING_EPSILON)
+{
+    if (abs(x - y) < epsilon)
+        return true;
+    return false;
+}
+
+static int sortBoxesRight(Geom::Rect const &a, Geom::Rect const &b)
+{
+    if (a.midpoint().x() < b.midpoint().x())
+        return 1;
+    return 0;
+}
+
+static int sortBoxesLeft(Geom::Rect const &a, Geom::Rect const &b)
+{
+    if (a.midpoint().x() > b.midpoint().x())
+        return 1;
+    return 0;
+}
+
+static int sortBoxesUp(Geom::Rect const &a, Geom::Rect const &b)
+{
+    if (a.midpoint().y() > b.midpoint().y())
+        return 1;
+    return 0;
+}
+
+static int sortBoxesDown(Geom::Rect const &a, Geom::Rect const &b)
+{
+    if (a.midpoint().y() < b.midpoint().y())
+        return 1;
+    return 0;
+}
+
+Inkscape::DistributionSnapper::DistributionSnapper(SnapManager *sm, Geom::Coord const d)
+    : Snapper(sm, d)
+{
+    _bboxes_right = std::make_unique<std::vector<Geom::Rect>>();
+    _bboxes_left = std::make_unique<std::vector<Geom::Rect>>();
+    _bboxes_up = std::make_unique<std::vector<Geom::Rect>>();
+    _bboxes_down = std::make_unique<std::vector<Geom::Rect>>();
+}
+
+Inkscape::DistributionSnapper::~DistributionSnapper()
+{
+    _bboxes_right->clear();
+    _bboxes_left->clear();
+    _bboxes_up->clear();
+    _bboxes_down->clear();
+}
+
+Geom::Coord Inkscape::DistributionSnapper::distRight(Geom::Rect const &a, Geom::Rect const &b)
+{
+    return -a.max().x() + b.min().x();
+}
+
+Geom::Coord Inkscape::DistributionSnapper::distLeft(Geom::Rect const &a, Geom::Rect const &b)
+{
+    return a.min().x() - b.max().x();
+}
+
+Geom::Coord Inkscape::DistributionSnapper::distUp(Geom::Rect const &a, Geom::Rect const &b)
+{
+    return a.min().y() - b.max().y();
+}
+
+Geom::Coord Inkscape::DistributionSnapper::distDown(Geom::Rect const &a, Geom::Rect const &b)
+{
+    return -a.max().y() + b.min().y();
+}
+
+bool Inkscape::DistributionSnapper::_findSidewaysSnaps(
+                                    Geom::Rect const &source_bbox,
+                                    std::vector<Geom::Rect>::iterator it,
+                                    std::vector<Geom::Rect>::iterator end,
+                                    std::vector<Geom::Rect> &vec,
+                                    Geom::Coord &dist,
+                                    Geom::Coord tol,
+                                    std::function<Geom::Coord(Geom::Rect const &, Geom::Rect const &)> const &distance_func,
+                                    int level) const
+{
+    std::vector<Geom::Rect>::iterator next_bbox = it;
+    std::vector<Geom::Rect>::iterator _next_bbox = it;
+
+    if (level == 0) {
+        int max_length = 0;
+
+        // check each consecutive box for a snap
+        Geom::Rect optimum_start;
+        while (std::next(next_bbox) != end) {
+            auto first_dist = distance_func(source_bbox, *next_bbox);
+            level = 0;
+
+            // temporary result for this particular item
+            std::vector<Geom::Rect> result;
+            if (_findSidewaysSnaps(*next_bbox, ++it, end, result, first_dist, tol, distance_func, ++level)) {
+                if (result.size() > max_length) {
+                    // if this item has the most number of items equidistant form each other
+                    // then make this the final result
+                    optimum_start = *next_bbox;
+                    max_length = result.size();
+                    vec = result;
+                    dist = first_dist;
+                }
+            }
+
+            ++next_bbox;
+        }
+
+        // if there is no snap, just add the first item and return false
+        // this is useful to find in-between snaps (see _snapEquidistantPoints())
+        if (max_length == 0) {
+            vec.push_back(*_next_bbox);
+            return false;
+        } else {
+            // insert the first item to the list, this does not happen automatically if level==1 (see below)
+            vec.insert(vec.begin(), optimum_start);
+            return true;
+        }
+    }
+
+    // if not the zeroth level
+    if (level != 1)
+        vec.push_back(source_bbox); 
+
+    if (it == end || level > 10)
+        return true;
+
+    int og_level = level;
+    std::vector<Geom::Rect> best_result;
+
+    while (next_bbox != end) {
+        level = og_level;
+        Geom::Coord this_dist;
+        Geom::Coord next_dist = distance_func(source_bbox, *next_bbox);
+
+        std::vector<Geom::Rect> temp_result;
+
+        if (level == 1 && compare_double(dist, next_dist, tol)){
+            // if this is the first level, check if the snap is within tolerance
+            // we cancel here if the possible snap in not whithing tolerance, saves us some time!
+            this_dist = next_dist;
+            if (_findSidewaysSnaps(*next_bbox, ++it, end, temp_result, this_dist, tol, distance_func, ++level)) {
+                if (temp_result.size() > 0) {
+                    dist = this_dist;
+                    best_result = temp_result;
+                    break;
+                }
+            }
+
+        } else if (compare_double(dist, next_dist, level * DISTRIBUTION_SNAPPING_EPSILON)) {
+
+            if (_findSidewaysSnaps(*next_bbox, ++it, end, temp_result, dist, tol, distance_func, ++level)) {
+                if (temp_result.size() > 0) {
+                    best_result = temp_result;
+                    break;
+                }
+            }
+        }
+
+        if (best_result.size() > 10)
+            break;
+
+        ++next_bbox;
+    }
+
+    vec.insert(vec.end(), best_result.begin(), best_result.end());
+    return true;
+}
+
+void Inkscape::DistributionSnapper::_collectBBoxes(Geom::OptRect const &bbox_to_snap, bool const &first_point) const
+{
+    if (!first_point)
+        return;
+
+    _bboxes_right->clear();
+    _bboxes_left->clear();
+    _bboxes_down->clear();
+    _bboxes_up->clear();
+
+    SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
+
+    Preferences *prefs = Preferences::get();
+    bool prefs_bbox = prefs->getBool("/tools/bounding_box");
+    bbox_type = !prefs_bbox ? SPItem::VISUAL_BBOX : SPItem::GEOMETRIC_BBOX;
+
+    // collect bounding boxes of other objects
+    for (const auto &candidate : *(_snapmanager->_align_snapper_candidates)) {
+        SPItem *root_item = candidate.item;
+
+        // get the root item in case we have a duplicate at hand
+        auto use = cast<SPUse>(candidate.item);
+        if (use) {
+            root_item = use->root();
+        }
+        g_return_if_fail(root_item);
+
+        // if candidate is not a clip or a mask object then extract its BBox points
+        if (!candidate.clip_or_mask) {
+            Geom::OptRect b = root_item->desktopBounds(bbox_type);
+            if (!b.intersects(bbox_to_snap)) {
+                auto diff_vec = b->midpoint() - bbox_to_snap->midpoint();
+
+                Geom::Rect Xbounds = *bbox_to_snap;
+                Xbounds.expandBy(_snapmanager->_desktop->get_display_area().maxExtent(), 0);
+
+                Geom::Rect Ybounds = *bbox_to_snap;
+                Ybounds.expandBy(0, _snapmanager->_desktop->get_display_area().maxExtent());
+
+                if (Xbounds.intersects(b)) {
+                    if (diff_vec.x() > 0) {
+                        _bboxes_right->push_back(*b);
+                    } else {
+                        _bboxes_left->push_back(*b);
+                    }
+                } else if (Ybounds.intersects(b)) {
+                    if (diff_vec.y() < 0) {
+                        _bboxes_up->push_back(*b);
+                    } else {
+                        _bboxes_down->push_back(*b);
+                    }
+                }
+            }
+        }
+    }
+
+    std::stable_sort(_bboxes_right->begin(), _bboxes_right->end(), sortBoxesRight);
+    std::stable_sort(_bboxes_left->begin(), _bboxes_left->end(), sortBoxesLeft);
+    std::stable_sort(_bboxes_up->begin(), _bboxes_up->end(), sortBoxesUp);
+    std::stable_sort(_bboxes_down->begin(), _bboxes_down->end(), sortBoxesDown);
+
+    _addBBoxForIntersectingBoxes(_bboxes_right.get(), Direction::RIGHT);
+    _addBBoxForIntersectingBoxes(_bboxes_left.get(), Direction::LEFT);
+    _addBBoxForIntersectingBoxes(_bboxes_up.get(), Direction::UP);
+    _addBBoxForIntersectingBoxes(_bboxes_down.get(), Direction::DOWN);
+}
+
+void Inkscape::DistributionSnapper::_addBBoxForIntersectingBoxes(std::vector<Geom::Rect> *vec, Direction dir) const {
+    if (vec->size() < 1) {
+        return;
+    }
+
+    int count = 0;
+    std::vector<std::pair<int, Geom::Rect>> insertPositions;
+
+    for (auto it = vec->begin(); it != vec->end(); it++, count++) {
+        Geom::Rect comb(*it);
+        int num = 0;
+        int insertPos = count;
+
+        while (std::next(it) != vec->end() && it->intersects(*std::next(it))) {
+            comb.unionWith(*std::next(it));
+            ++it;
+            ++num;
+            ++count;
+        }
+
+        if (num > 0) {
+            insertPositions.emplace_back(insertPos, comb);
+        }
+    }
+    
+    if (insertPositions.size() != 0) {
+        // TODO: Does this improve performance?
+        vec->reserve(vec->size() + insertPositions.size());
+
+        count = 0;
+        for (auto pair : insertPositions) {
+            vec->insert(vec->begin() + pair.first + count, pair.second);
+            ++count;
+        }
+    }
+}
+
+void Inkscape::DistributionSnapper::_snapEquidistantPoints(IntermSnapResults &isr,
+                                                           SnapCandidatePoint const &p,
+                                                           Geom::OptRect const &bbox_to_snap,
+                                                           std::vector<SnapCandidatePoint> *unselected_nodes,
+                                                           SnapConstraint const &c,
+                                                           Geom::Point const &p_proj_on_constraint) const
+{
+    bool consider_x = true;
+    bool consider_y = true;
+    if (!c.isUndefined() && c.isLinear()) {
+        if (c.getDirection().x() == 0)
+            consider_x = false; // consider horizontal snapping if moving vertically
+        else
+            consider_y = false; // consider vertical snapping if moving horizontally
+    }
+
+    _collectBBoxes(bbox_to_snap, p.getSourceNum() <= 0);
+
+    Geom::Coord offset;
+
+    if (p.getSourceType() != SNAPSOURCE_BBOX_MIDPOINT)
+        return;
+
+    Geom::Coord equal_dist;
+
+    SnappedPoint sr, sl, sx, su, sd, sy;
+    Geom::Coord dist_x, dist_y;
+    bool snap_x = false, snap_y = false;
+
+    // 1. look right
+    // if there is a snap then add right bboxes and look left, if there is a snap to the left then
+    // add those bboxes too
+    std::vector<Geom::Rect> vecRight;
+    std::vector<Geom::Rect> vecLeft;
+    if (consider_x && _bboxes_right->size() > 0) {
+        if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_right->begin(), _bboxes_right->end(), vecRight, equal_dist, getSnapperTolerance(), &DistributionSnapper::distRight)) {
+            auto first_dist = distRight(*bbox_to_snap, vecRight.front());
+            Geom::Coord offset = first_dist - equal_dist;
+            Geom::Point target = bbox_to_snap->midpoint() + Geom::Point(offset, 0);
+
+            Geom::Affine translation = Geom::Translate(target - bbox_to_snap->midpoint());
+            Geom::Rect bbox = *bbox_to_snap * translation;
+            vecRight.insert(vecRight.begin(), bbox);
+
+            _correctSelectionBBox(target, p.getPoint(), *bbox_to_snap);
+
+            if (_bboxes_left->size() > 0) {
+                first_dist = distLeft(bbox, _bboxes_left->front());
+                Geom::Coord left_dist;
+                vecLeft.clear();
+                if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_left->begin(), _bboxes_left->end(), vecLeft, left_dist, getSnapperTolerance(), &DistributionSnapper::distLeft)) {
+                    if (compare_double(left_dist, equal_dist)) {
+                        std::reverse(vecLeft.begin(), vecLeft.end());
+                        vecRight.insert(vecRight.begin(), vecLeft.begin(), vecLeft.end());
+                    }
+
+                } else if (compare_double(first_dist, equal_dist)) {
+                    vecRight.insert(vecRight.begin(), vecLeft.front());
+                }
+            }
+
+            dist_x = abs(offset);
+            sx = SnappedPoint(target, vecRight, bbox, equal_dist, p.getSourceType(), p.getSourceNum(), SNAPTARGET_DISTRIBUTION_RIGHT, dist_x, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true);
+            snap_x = true;
+        }
+    }
+
+    // 2. if no snap to right, look left
+    // if there is a snap then add left bboxes and right left, if there is a snap to the right then
+    // add those bboxes too
+    if (consider_x && !snap_x && _bboxes_left->size() > 0) {
+        vecLeft.clear();
+        if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_left->begin(), _bboxes_left->end(), vecLeft, equal_dist, getSnapperTolerance(), &DistributionSnapper::distLeft)) {
+            auto first_dist = distLeft(*bbox_to_snap, vecLeft.front());
+            Geom::Coord offset = first_dist - equal_dist;
+            Geom::Point target = bbox_to_snap->midpoint() - Geom::Point(offset, 0);
+
+            // translate the source bbox to the snap position
+            Geom::Affine translation = Geom::Translate(target - bbox_to_snap->midpoint());
+            Geom::Rect bbox = *bbox_to_snap * translation;
+            std::reverse(vecLeft.begin(), vecLeft.end());
+            vecLeft.push_back(bbox);
+
+            _correctSelectionBBox(target, p.getPoint(), *bbox_to_snap);
+
+            if (_bboxes_right->size() > 0) {
+                first_dist = distRight(bbox, _bboxes_right->front());
+                Geom::Coord right_dist;
+                vecRight.clear();
+                if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_right->begin(), _bboxes_right->end(), vecRight, right_dist, getSnapperTolerance(), &DistributionSnapper::distRight)) {
+                    if (compare_double(right_dist, equal_dist)) {
+                        vecLeft.insert(vecLeft.end(), vecRight.begin(), vecRight.end());
+                    }
+
+                } else if (compare_double(first_dist, equal_dist)) {
+                    vecLeft.push_back(vecRight.front());
+                }
+            }
+
+            dist_x = abs(offset);
+            sx = SnappedPoint(target, vecLeft, bbox, equal_dist, p.getSourceType(), p.getSourceNum(), SNAPTARGET_DISTRIBUTION_LEFT, dist_x, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true);
+            snap_x = true;
+        }
+    }
+
+    // 3. if no snap to right or left just add the center snap
+    if (consider_x && !snap_x && vecRight.size() > 0 && vecLeft.size() > 0) {
+        auto x = Geom::Point((vecRight.front().min() + vecLeft.front().max()) / 2).x();
+        offset = abs(x - bbox_to_snap->midpoint().x());
+        if (offset < getSnapperTolerance()) {
+            Geom::Point target = Geom::Point(x, bbox_to_snap->midpoint().y());
+            // translate the source bbox to the snap position
+            Geom::Affine translation = Geom::Translate(target - bbox_to_snap->midpoint());
+            Geom::Rect bbox = *bbox_to_snap * translation;
+            std::vector<Geom::Rect> bboxes = {vecLeft.front(), bbox, vecRight.front()};
+
+            _correctSelectionBBox(target, p.getPoint(), *bbox_to_snap);
+
+            equal_dist = bbox.min().x() - vecLeft.front().max().x();
+            sx = SnappedPoint(target, bboxes, bbox, equal_dist, p.getSourceType(), p.getSourceNum(), SNAPTARGET_DISTRIBUTION_X, offset, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true);
+            snap_x = true;
+        }
+    }
+
+    // 1. look Up
+    // if there is a snap then add top bboxes and look down, if there is a snap at the bottom then
+    // add those bboxes too
+    std::vector<Geom::Rect> vecUp;
+    std::vector<Geom::Rect> vecDown;
+    if (consider_y && _bboxes_up->size() > 0) {
+        if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_up->begin(), _bboxes_up->end(), vecUp, equal_dist, getSnapperTolerance(), &DistributionSnapper::distUp)) {
+            auto first_dist = distUp(*bbox_to_snap, vecUp.front());
+            Geom::Coord offset = first_dist - equal_dist;
+            Geom::Point target = bbox_to_snap->midpoint() - Geom::Point(0, offset);
+
+            // translate the source bbox to the snap position
+            Geom::Affine translation = Geom::Translate(target - bbox_to_snap->midpoint());
+            Geom::Rect bbox = *bbox_to_snap * translation;
+            std::reverse(vecUp.begin(), vecUp.end());
+            vecUp.push_back(bbox);
+
+            _correctSelectionBBox(target, p.getPoint(), *bbox_to_snap);
+
+            if (_bboxes_down->size() > 0) {
+                first_dist = distDown(bbox, _bboxes_down->front());
+                Geom::Coord down_dist;
+                vecDown.clear();
+                if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_down->begin(), _bboxes_down->end(), vecDown, down_dist,
+                                      getSnapperTolerance(), &DistributionSnapper::distDown)) {
+                    if (abs(down_dist - equal_dist) < 1e-4) {
+                        vecUp.insert(vecUp.end(), vecDown.begin(), vecDown.end());
+                    }
+
+                } else if (abs(first_dist - equal_dist) < 1e-4) {
+                    vecUp.insert(vecUp.end(), vecDown.front());
+                }
+            }
+
+            dist_y = abs(offset);
+            sy = SnappedPoint(target, vecUp, bbox, equal_dist, p.getSourceType(), p.getSourceNum(), SNAPTARGET_DISTRIBUTION_UP, dist_y, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true);
+            snap_y = true;
+        }
+    }
+
+    // 2. if no snaps on top, look Down
+    // if there is a snap then add bottom bboxes and look Up, if there is a snap above then
+    // add those bboxes too
+    if (consider_y && !snap_y && _bboxes_down->size() > 0) {
+        vecDown.clear();
+        if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_down->begin(), _bboxes_down->end(), vecDown, equal_dist, getSnapperTolerance(), &DistributionSnapper::distDown)) {
+            auto first_dist = distDown(*bbox_to_snap, vecDown.front());
+            Geom::Coord offset = first_dist - equal_dist;
+            Geom::Point target = bbox_to_snap->midpoint() + Geom::Point(0, offset);
+
+            // translate the source bbox to the snap position
+            Geom::Affine translation = Geom::Translate(target - bbox_to_snap->midpoint());
+            Geom::Rect bbox = *bbox_to_snap * translation;
+            vecDown.insert(vecDown.begin(), bbox);
+
+            _correctSelectionBBox(target, p.getPoint(), *bbox_to_snap);
+
+            if (_bboxes_up->size() > 0) {
+                first_dist = distUp(bbox, _bboxes_up->front());
+                Geom::Coord up_dist;
+                vecUp.clear();
+
+                if (_findSidewaysSnaps(*bbox_to_snap, _bboxes_up->begin(), _bboxes_up->end(), vecUp, up_dist, getSnapperTolerance(), &DistributionSnapper::distUp)) {
+                    if (compare_double(up_dist, equal_dist)) {
+                        std::reverse(vecUp.begin(), vecUp.end());
+                        vecDown.insert(vecDown.begin(), vecUp.begin(), vecUp.end());
+                    }
+                } else if (compare_double(first_dist, equal_dist)) {
+                    vecDown.insert(vecDown.begin(), vecUp.front());
+                }
+            }
+
+            dist_y = abs(offset);
+            sy = SnappedPoint(target, vecDown, bbox, equal_dist, p.getSourceType(), p.getSourceNum(), SNAPTARGET_DISTRIBUTION_DOWN, dist_y, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true);
+            snap_y = true;
+        }
+    }
+
+    // 3. if no snap to right or left just add the center snap
+    if (consider_y && !snap_y && vecUp.size() > 0 && vecDown.size() > 0) {
+        auto y = Geom::Point((vecUp.front().max() + vecDown.front().min()) / 2).y();
+        offset = abs(y - bbox_to_snap->midpoint().y());
+        if (consider_y && offset < getSnapperTolerance()) {
+            Geom::Point target = Geom::Point(bbox_to_snap->midpoint().x(), y);
+            // translate the source bbox to the snap position
+            Geom::Affine translation = Geom::Translate(target - bbox_to_snap->midpoint());
+            Geom::Rect bbox = *bbox_to_snap * translation;
+            std::vector<Geom::Rect> bboxes = {vecUp.front(), bbox, vecDown.front()};
+
+            _correctSelectionBBox(target, p.getPoint(), *bbox_to_snap);
+
+            equal_dist = bbox.min().y() - vecUp.front().max().y();
+            sy = SnappedPoint(target, bboxes, bbox, equal_dist, p.getSourceType(), p.getSourceNum(), SNAPTARGET_DISTRIBUTION_Y, offset, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true);
+            snap_y = true;
+        }
+    }
+
+    if (snap_x && snap_y) {
+        Geom::Point target = Geom::Point(sx.getPoint().x(), sy.getPoint().y());
+        Geom::Affine translation = Geom::Translate(target - bbox_to_snap->midpoint());
+        Geom::Rect bbox = *bbox_to_snap * translation;
+        std::vector<Geom::Rect> bboxes_x = sx.getBBoxes();
+        std::vector<Geom::Rect> bboxes_y = sy.getBBoxes();
+
+        // Do not need to correct here, already did that earlier for each direction separately
+        //_correctSelectionBBox(target, p.getPoint(), *bbox_to_snap);
+        auto si = SnappedPoint(target, bboxes_x, bboxes_y, bbox, sx.getDistributionDistance(), sy.getDistributionDistance(), p.getSourceType(), p.getSourceNum(), SNAPTARGET_DISTRIBUTION_XY, offset, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true);
+        isr.points.push_back(si);
+        return;
+    }
+
+    if (snap_x) {
+        isr.points.push_back(sx);
+    }
+
+    if (snap_y) {
+        isr.points.push_back(sy);
+    }
+}
+
+void Inkscape::DistributionSnapper::_correctSelectionBBox(Geom::Point &target,
+                                                          Geom::Point const &p,
+                                                          Geom::Rect const &bbox_to_snap) const
+{
+    if (_snapmanager->_desktop->getSelection()->size() > 1) {
+        auto correction = bbox_to_snap.midpoint() - p;
+        target -= correction;
+    }
+}
+
+void Inkscape::DistributionSnapper::freeSnap(IntermSnapResults &isr,
+                                             Inkscape::SnapCandidatePoint const &p,
+                                             Geom::OptRect const &bbox_to_snap,
+                                             std::vector<SPObject const *> const *it,
+                                             std::vector<SnapCandidatePoint> *unselected_nodes) const
+{
+    if (bbox_to_snap.empty())
+        return;
+
+    if (!(p.getSourceType() & SNAPSOURCE_BBOX_CATEGORY)) {
+        return;
+    }
+
+    // toggle checks
+    if (!_snap_enabled || !_snapmanager->snapprefs.isTargetSnappable(SNAPTARGET_DISTRIBUTION_CATEGORY))
+        return;
+
+    if (p.getSourceNum() <= 0) {
+        Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
+        _snapmanager->_findCandidates(_snapmanager->getDocument()->getRoot(), it, local_bbox_to_snap, false, Geom::identity());
+    }
+
+    _snapEquidistantPoints(isr, p, bbox_to_snap, unselected_nodes);
+}
+
+void Inkscape::DistributionSnapper::constrainedSnap(IntermSnapResults &isr,
+                                                    Inkscape::SnapCandidatePoint const &p,
+                                                    Geom::OptRect const &bbox_to_snap,
+                                                    SnapConstraint const &c,
+                                                    std::vector<SPObject const *> const *it,
+                                                    std::vector<SnapCandidatePoint> *unselected_nodes) const
+{
+    if (bbox_to_snap.empty())
+        return;
+
+    // toggle checks
+    if (!_snap_enabled || !_snapmanager->snapprefs.isTargetSnappable(SNAPTARGET_DISTRIBUTION_CATEGORY))
+        return;
+
+    // project the mouse pointer onto the constraint. Only the projected point will be considered for snapping
+    Geom::Point pp = c.projection(p.getPoint());
+
+    if (p.getSourceNum() <= 0) {
+        Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
+        _snapmanager->_findCandidates(_snapmanager->getDocument()->getRoot(), it, local_bbox_to_snap, false, Geom::identity());
+    }
+
+    _snapEquidistantPoints(isr, p, bbox_to_snap, unselected_nodes, c, pp);
+}
+
+bool Inkscape::DistributionSnapper::ThisSnapperMightSnap() const
+{
+    return true;
+}
+
+bool Inkscape::DistributionSnapper::getSnapperAlwaysSnap() const
+{
+    // TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
+    return _snapmanager->snapprefs.getDistributionTolerance() == 10000;
+}
+
+Geom::Coord Inkscape::DistributionSnapper::getSnapperTolerance() const
+{
+    SPDesktop const *dt = _snapmanager->getDesktop();
+    double const zoom = dt ? dt->current_zoom() : 1;
+    return _snapmanager->snapprefs.getDistributionTolerance() / zoom;
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :