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diff --git a/src/snap.cpp b/src/snap.cpp
index 218cbb0293de6f42c082f78fbacd57f3e8d3e0bc..cb4ea3f5882af10ed7bad80830513ccbb4935728 100644 (file)
--- a/src/snap.cpp
+++ b/src/snap.cpp
* Authors:
* Lauris Kaplinski <lauris@kaplinski.com>
* Frank Felfe <innerspace@iname.com>
+ * Nathan Hurst <njh@njhurst.com>
* Carl Hetherington <inkscape@carlh.net>
+ * Diederik van Lierop <mail@diedenrezi.nl>
*
- * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
+ * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
+ * Copyrigth (C) 2004 Nathan Hurst
* Copyright (C) 1999-2002 Authors
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
+#include <utility>
+
#include "sp-namedview.h"
#include "snap.h"
+#include "snapped-line.h"
#include <libnr/nr-point-fns.h>
#include <libnr/nr-scale-ops.h>
#include "inkscape.h"
#include "desktop.h"
+#include "sp-guide.h"
+using std::vector;
/**
* Construct a SnapManager for a SPNamedView.
SnapManager::SnapManager(SPNamedView const *v) :
guide(v, 0),
object(v, 0),
- _named_view(v)
-{
-
+ _named_view(v),
+ _include_item_center(false),
+ _snap_enabled_globally(true)
+{
}
bool SnapManager::SomeSnapperMightSnap() const
{
+ if (!_snap_enabled_globally) {
+ return false;
+ }
+
SnapperList const s = getSnappers();
SnapperList::const_iterator i = s.begin();
while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
i++;
}
-
return (i != s.end());
}
+/*
+ * The snappers have too many parameters to adjust individually. Therefore only
+ * two snapping modes are presented to the user: snapping bounding box corners (to
+ * other bounding boxes, grids or guides), and/or snapping nodes (to other nodes,
+ * paths, grids or guides). To select either of these modes (or both), use the
+ * methods defined below: setSnapModeBBox() and setSnapModeNode().
+ *
+ * */
+
+
void SnapManager::setSnapModeBBox(bool enabled)
{
- guide.setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
- object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
- object.setSnapToBBoxNodes(enabled);
- object.setSnapToBBoxPaths(enabled);
- object.setStrictSnapping(true);
+ //The default values are being set in sp_namedview_set() (in sp-namedview.cpp)
+ guide.setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
+
+ for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
+ Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
+ grid->snapper->setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
+ }
+
+ object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
+ //object.setSnapToBBoxNode(enabled); // On second thought, these should be controlled
+ //object.setSnapToBBoxPath(enabled); // separately by the snapping prefs dialog
+ object.setStrictSnapping(true); //don't snap bboxes to nodes/paths and vice versa
}
bool SnapManager::getSnapModeBBox() const
{
- return guide.getSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX);
+ return guide.getSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX);
}
+void SnapManager::setSnapModeNode(bool enabled)
+{
+ guide.setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
+
+ for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
+ Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
+ grid->snapper->setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
+ }
+
+ object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
+ //object.setSnapToItemNode(enabled); // On second thought, these should be controlled
+ //object.setSnapToItemPath(enabled); // separately by the snapping prefs dialog
+ object.setStrictSnapping(true);
+}
+
+bool SnapManager::getSnapModeNode() const
+{
+ return guide.getSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE);
+}
-void SnapManager::setSnapModeNodes(bool enabled)
+void SnapManager::setSnapModeGuide(bool enabled)
{
- guide.setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
- object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
- object.setSnapToItemNodes(enabled);
- object.setSnapToItemPaths(enabled);
- object.setStrictSnapping(true);
+ object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_GUIDE, enabled);
}
-bool SnapManager::getSnapModeNodes() const
+bool SnapManager::getSnapModeGuide() const
{
- return guide.getSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE);
+ return object.getSnapFrom(Inkscape::Snapper::SNAPPOINT_GUIDE);
}
/**
{
std::list<SPItem const *> lit;
lit.push_back(it);
- return freeSnap(t, p, lit);
-}
-
-
-/**
- * Try to snap a point to any interested snappers.
- *
- * \param t Type of point.
- * \param p Point.
- * \param it List of items to ignore when snapping.
- * \return Snapped point.
- */
-
-Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::Snapper::PointType t,
- NR::Point const &p,
- std::list<SPItem const *> const &it) const
-{
- SnapperList const snappers = getSnappers();
-
- return freeSnap(t, p, it, snappers);
+
+ std::vector<NR::Point> points_to_snap;
+ points_to_snap.push_back(p);
+
+ return freeSnap(t, p, true, points_to_snap, lit);
}
/**
*
* \param t Type of point.
* \param p Point.
+ * \param first_point If true then this point is the first one from a whole bunch of points
+ * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
* \param it List of items to ignore when snapping.
* \param snappers List of snappers to try to snap to
* \return Snapped point.
Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::Snapper::PointType t,
NR::Point const &p,
- std::list<SPItem const *> const &it,
- SnapperList const &snappers) const
+ bool const &first_point,
+ std::vector<NR::Point> &points_to_snap,
+ std::list<SPItem const *> const &it) const
{
- Inkscape::SnappedPoint r(p, NR_HUGE);
-
- for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
- Inkscape::SnappedPoint const s = (*i)->freeSnap(t, p, it);
- if (s.getDistance() < r.getDistance()) {
- r = s;
- }
+ if (!SomeSnapperMightSnap()) {
+ return Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
}
+
+ SnappedConstraints sc;
+
+ SnapperList const snappers = getSnappers();
- return r;
-}
-
-/**
- * Try to snap a point to any of the specified snappers. Snap always, ignoring the snap-distance
- *
- * \param t Type of point.
- * \param p Point.
- * \param it Item to ignore when snapping.
- * \param snappers List of snappers to try to snap to
- * \return Snapped point.
- */
-
-Inkscape::SnappedPoint
-SnapManager::freeSnapAlways( Inkscape::Snapper::PointType t,
- NR::Point const &p,
- SPItem const *it,
- SnapperList &snappers )
-{
- std::list<SPItem const *> lit;
- lit.push_back(it);
- return freeSnapAlways(t, p, lit, snappers);
-}
-
-/**
- * Try to snap a point to any of the specified snappers. Snap always, ignoring the snap-distance
- *
- * \param t Type of point.
- * \param p Point.
- * \param it List of items to ignore when snapping.
- * \param snappers List of snappers to try to snap to
- * \return Snapped point.
- */
-
-Inkscape::SnappedPoint
-SnapManager::freeSnapAlways( Inkscape::Snapper::PointType t,
- NR::Point const &p,
- std::list<SPItem const *> const &it,
- SnapperList &snappers )
-{
- Inkscape::SnappedPoint r(p, NR_HUGE);
-
- for (SnapperList::iterator i = snappers.begin(); i != snappers.end(); i++) {
- gdouble const curr_gridsnap = (*i)->getDistance();
- const_cast<Inkscape::Snapper*> (*i)->setDistance(NR_HUGE);
- Inkscape::SnappedPoint const s = (*i)->freeSnap(t, p, it);
- const_cast<Inkscape::Snapper*> (*i)->setDistance(curr_gridsnap);
-
- if (s.getDistance() < r.getDistance()) {
- r = s;
- }
+ for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
+ (*i)->freeSnap(sc, t, p, first_point, points_to_snap, it);
}
- return r;
+ return findBestSnap(p, sc, false);
}
-
-
/**
* Try to snap a point to any interested snappers. A snap will only occur along
* a line described by a Inkscape::Snapper::ConstraintLine.
@@ -261,7 +241,11 @@ Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType
{
std::list<SPItem const *> lit;
lit.push_back(it);
- return constrainedSnap(t, p, c, lit);
+
+ std::vector<NR::Point> points_to_snap;
+ points_to_snap.push_back(p);
+
+ return constrainedSnap(t, p, true, points_to_snap, c, lit);
}
@@ -272,6 +256,8 @@ Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType
*
* \param t Type of point.
* \param p Point.
+ * \param first_point If true then this point is the first one from a whole bunch of points
+ * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
* \param c Constraint line.
* \param it List of items to ignore when snapping.
* \return Snapped point.
@@ -279,22 +265,39 @@ Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType
Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType t,
NR::Point const &p,
+ bool const &first_point,
+ std::vector<NR::Point> &points_to_snap,
Inkscape::Snapper::ConstraintLine const &c,
std::list<SPItem const *> const &it) const
{
- Inkscape::SnappedPoint r(p, NR_HUGE);
-
+ if (!SomeSnapperMightSnap()) {
+ return Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
+ }
+
+ SnappedConstraints sc;
+
SnapperList const snappers = getSnappers();
for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
- Inkscape::SnappedPoint const s = (*i)->constrainedSnap(t, p, c, it);
- if (s.getDistance() < r.getDistance()) {
- r = s;
- }
+ (*i)->constrainedSnap(sc, t, p, first_point, points_to_snap, c, it);
}
- return r;
+ return findBestSnap(p, sc, true);
}
+Inkscape::SnappedPoint SnapManager::guideSnap(NR::Point const &p,
+ NR::Point const &guide_normal) const
+{
+ // This method is used to snap a guide to nodes, while dragging the guide around
+
+ if (!(object.GuidesMightSnap() && _snap_enabled_globally)) {
+ return Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
+ }
+
+ SnappedConstraints sc;
+ object.guideSnap(sc, p, guide_normal);
+
+ return findBestSnap(p, sc, false);
+}
/**
@@ -311,7 +314,7 @@ Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType
* \param transformation Description of the transformation; details depend on the type.
* \param origin Origin of the transformation, if applicable.
* \param dim Dimension of the transformation, if applicable.
- * \param uniform true if the transformation should be uniform, if applicable.
+ * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
*/
std::pair<NR::Point, bool> SnapManager::_snapTransformed(
** appropriate transformation with `true'; otherwise we return the original scale with `false'.
*/
- /* Quick check to see if we have any snappers that are enabled */
+ /* Quick check to see if we have any snappers that are enabled
+ ** Also used to globally disable all snapping
+ */
if (SomeSnapperMightSnap() == false) {
return std::make_pair(transformation, false);
}
-
- /* The current best transformation */
- NR::Point best_transformation = transformation;
-
- /* The current best metric for the best transformation; lower is better, NR_HUGE
- ** means that we haven't snapped anything.
- */
- double best_metric = NR_HUGE;
-
+
+ std::vector<NR::Point> transformed_points;
+
for (std::vector<NR::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
/* Work out the transformed version of this point */
default:
g_assert_not_reached();
}
+
+ // add the current transformed point to the box hulling all transformed points
+ transformed_points.push_back(transformed);
+ }
+
+ /* The current best transformation */
+ NR::Point best_transformation = transformation;
+
+ /* The current best metric for the best transformation; lower is better, NR_HUGE
+ ** means that we haven't snapped anything.
+ */
+ NR::Coord best_metric = NR_HUGE;
+ NR::Coord best_second_metric = NR_HUGE;
+ NR::Point best_scale_metric(NR_HUGE, NR_HUGE);
+ bool best_at_intersection = false;
+ bool best_always_snap = false;
- /* Snap it */
- Inkscape::SnappedPoint const snapped = constrained ?
- constrainedSnap(type, transformed, constraint, ignore) : freeSnap(type, transformed, ignore);
+ std::vector<NR::Point>::const_iterator j = transformed_points.begin();
+
+ //std::cout << std::endl;
+
+ for (std::vector<NR::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
+
+ /* Snap it */
+ Inkscape::SnappedPoint snapped;
+
+ if (constrained) {
+ Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
+ if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
+ // When uniformly scaling, each point will have its own unique constraint line,
+ // running from the scaling origin to the original untransformed point. We will
+ // calculate that line here
+ dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, (*i) - origin);
+ } else if (transformation_type == STRETCH || transformation_type == SKEW) { // when skewing or non-uniform stretching {
+ dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i), component_vectors[dim]);
+ } // else: leave the original constraint, e.g. for constrained translation
+ if (transformation_type == SCALE && !uniform) {
+ g_warning("Non-uniform constrained scaling is not supported!");
+ }
+ snapped = constrainedSnap(type, *j, i == points.begin(), transformed_points, dedicated_constraint, ignore);
+ } else {
+ snapped = freeSnap(type, *j, i == points.begin(), transformed_points, ignore);
+ }
+ NR::Point result;
+ NR::Coord metric = NR_HUGE;
+ NR::Coord second_metric = NR_HUGE;
+ NR::Point scale_metric(NR_HUGE, NR_HUGE);
+
if (snapped.getDistance() < NR_HUGE) {
/* We snapped. Find the transformation that describes where the snapped point has
** ended up, and also the metric for this transformation.
*/
- NR::Point result;
- NR::Coord metric;
+ NR::Point const a = (snapped.getPoint() - origin); // vector to snapped point
+ NR::Point const b = (*i - origin); // vector to original point
+
switch (transformation_type) {
case TRANSLATION:
result = snapped.getPoint() - *i;
- metric = NR::L2(result);
+ /* Consider the case in which a box is almost aligned with a grid in both
+ * horizontal and vertical directions. The distance to the intersection of
+ * the grid lines will always be larger then the distance to a single grid
+ * line. If we prefer snapping to an intersection instead of to a single
+ * grid line, then we cannot use "metric = NR::L2(result)". Therefore the
+ * snapped distance will be used as a metric. Please note that the snapped
+ * distance is defined as the distance to the nearest line of the intersection,
+ * and not to the intersection itself!
+ */
+ metric = snapped.getDistance(); //used to be: metric = NR::L2(result);
+ second_metric = snapped.getSecondDistance();
break;
case SCALE:
{
- NR::Point const a = (snapped.getPoint() - origin);
- NR::Point const b = (*i - origin);
- result = NR::Point(a[NR::X] / b[NR::X], a[NR::Y] / b[NR::Y]);
- metric = std::abs(NR::L2(result) - NR::L2(transformation));
+ result = NR::Point(NR_HUGE, NR_HUGE);
+ // If this point *i is horizontally or vertically aligned with
+ // the origin of the scaling, then it will scale purely in X or Y
+ // We can therefore only calculate the scaling in this direction
+ // and the scaling factor for the other direction should remain
+ // untouched (unless scaling is uniform ofcourse)
+ for (int index = 0; index < 2; index++) {
+ if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
+ if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
+ result[index] = a[index] / b[index]; // then calculate it!
+ }
+ // we might leave result[1-index] = NR_HUGE
+ // if scaling didn't occur in the other direction
+ }
+ }
+ // Compare the resulting scaling with the desired scaling
+ scale_metric = result - transformation; // One or both of its components might be NR_HUGE
break;
}
case STRETCH:
- {
- for (int j = 0; j < 2; j++) {
- if (uniform || j == dim) {
- result[j] = (snapped.getPoint()[dim] - origin[dim]) / ((*i)[dim] - origin[dim]);
- } else {
- result[j] = 1;
+ result = NR::Point(NR_HUGE, NR_HUGE);
+ if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
+ result[dim] = a[dim] / b[dim];
+ result[1-dim] = uniform ? result[dim] : 1;
+ } else { // STRETCHING might occur for this point, but only when the stretching is uniform
+ if (uniform && fabs(b[1-dim]) > 1e-6) {
+ result[1-dim] = a[1-dim] / b[1-dim];
+ result[dim] = result[1-dim];
}
}
metric = std::abs(result[dim] - transformation[dim]);
break;
- }
case SKEW:
result[dim] = (snapped.getPoint()[dim] - (*i)[dim]) / ((*i)[1 - dim] - origin[1 - dim]);
metric = std::abs(result[dim] - transformation[dim]);
default:
g_assert_not_reached();
}
-
+
/* Note it if it's the best so far */
- if (metric < best_metric && metric != 0) {
- best_transformation = result;
- best_metric = metric;
+ if (transformation_type == SCALE) {
+ for (int index = 0; index < 2; index++) {
+ if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
+ best_transformation[index] = result[index];
+ best_scale_metric[index] = fabs(scale_metric[index]);
+ //std::cout << "SEL ";
+ } //else { std::cout << " ";}
+ }
+ if (uniform) {
+ if (best_scale_metric[0] < best_scale_metric[1]) {
+ best_transformation[1] = best_transformation[0];
+ best_scale_metric[1] = best_scale_metric[0];
+ } else {
+ best_transformation[0] = best_transformation[1];
+ best_scale_metric[0] = best_scale_metric[1];
+ }
+ }
+ best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
+ //std::cout << "P_orig = " << (*i) << " | scale_metric = " << scale_metric << " | distance = " << snapped.getDistance() << " | P_snap = " << snapped.getPoint() << std::endl;
+ } else {
+ bool const c1 = metric < best_metric;
+ bool const c2 = metric == best_metric && snapped.getAtIntersection() == true && best_at_intersection == false;
+ bool const c3a = metric == best_metric && snapped.getAtIntersection() == true && best_at_intersection == true;
+ bool const c3b = second_metric < best_second_metric;
+ bool const c4 = snapped.getAlwaysSnap() == true && best_always_snap == false;
+ bool const c4n = snapped.getAlwaysSnap() == false && best_always_snap == true;
+
+ if ((c1 || c2 || (c3a && c3b) || c4) && !c4n) {
+ best_transformation = result;
+ best_metric = metric;
+ best_second_metric = second_metric;
+ best_at_intersection = snapped.getAtIntersection();
+ best_always_snap = snapped.getAlwaysSnap();
+ //std::cout << "SEL ";
+ } //else { std::cout << " ";}
+ //std::cout << "P_orig = " << (*i) << " | metric = " << metric << " | distance = " << snapped.getDistance() << " | second metric = " << second_metric << " | P_snap = " << snapped.getPoint() << std::endl;
}
}
+
+ j++;
}
-
- // Using " < 1e6" instead of " < NR::HUGE" for catching some rounding errors
+
+ if (transformation_type == SCALE) {
+ // When scaling, don't ever exit with one of scaling components set to NR_HUGE
+ for (int index = 0; index < 2; index++) {
+ if (best_transformation[index] == NR_HUGE) {
+ if (uniform && best_transformation[1-index] < NR_HUGE) {
+ best_transformation[index] = best_transformation[1-index];
+ } else {
+ best_transformation[index] = transformation[index];
+ }
+ }
+ }
+ }
+
+ // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
// These rounding errors might be caused by NRRects, see bug #1584301
return std::make_pair(best_transformation, best_metric < 1e6);
}
@@ -519,12 +635,12 @@ std::pair<NR::scale, bool> SnapManager::freeSnapScale(Inkscape::Snapper::PointTy
std::pair<NR::scale, bool> SnapManager::constrainedSnapScale(Inkscape::Snapper::PointType t,
std::vector<NR::Point> const &p,
std::list<SPItem const *> const &it,
- Inkscape::Snapper::ConstraintLine const &c,
NR::scale const &s,
NR::Point const &o) const
{
+ // When constrained scaling, only uniform scaling is supported.
return _snapTransformed(
- t, p, it, true, c, SCALE, NR::Point(s[NR::X], s[NR::Y]), o, NR::X, false
+ t, p, it, true, NR::Point(), SCALE, NR::Point(s[NR::X], s[NR::Y]), o, NR::X, true
);
}
@@ -543,7 +659,7 @@ std::pair<NR::scale, bool> SnapManager::constrainedSnapScale(Inkscape::Snapper::
* \return Snapped stretch, if a snap occurred, and a flag indicating whether a snap occurred.
*/
-std::pair<NR::Coord, bool> SnapManager::freeSnapStretch(Inkscape::Snapper::PointType t,
+std::pair<NR::Coord, bool> SnapManager::constrainedSnapStretch(Inkscape::Snapper::PointType t,
std::vector<NR::Point> const &p,
std::list<SPItem const *> const &it,
NR::Coord const &s,
@@ -552,7 +668,7 @@ std::pair<NR::Coord, bool> SnapManager::freeSnapStretch(Inkscape::Snapper::Point
bool u) const
{
std::pair<NR::Point, bool> const r = _snapTransformed(
- t, p, it, false, NR::Point(), STRETCH, NR::Point(s, s), o, d, u
+ t, p, it, true, NR::Point(), STRETCH, NR::Point(s, s), o, d, u
);
return std::make_pair(r.first[d], r.second);
@@ -586,6 +702,98 @@ std::pair<NR::Coord, bool> SnapManager::freeSnapSkew(Inkscape::Snapper::PointTyp
return std::make_pair(r.first[d], r.second);
}
+Inkscape::SnappedPoint SnapManager::findBestSnap(NR::Point const &p, SnappedConstraints &sc, bool constrained) const
+{
+ // Store all snappoints
+ std::list<Inkscape::SnappedPoint> sp_list;
+
+ // search for the closest snapped point
+ Inkscape::SnappedPoint closestPoint;
+ if (getClosestSP(sc.points, closestPoint)) {
+ sp_list.push_back(closestPoint);
+ }
+
+ // search for the closest snapped line segment
+ Inkscape::SnappedLineSegment closestLineSegment;
+ if (getClosestSLS(sc.lines, closestLineSegment)) {
+ sp_list.push_back(Inkscape::SnappedPoint(closestLineSegment));
+ }
+
+ if (_intersectionLS) {
+ // search for the closest snapped intersection of line segments
+ Inkscape::SnappedPoint closestLineSegmentIntersection;
+ if (getClosestIntersectionSLS(sc.lines, closestLineSegmentIntersection)) {
+ sp_list.push_back(closestLineSegmentIntersection);
+ }
+ }
+
+ // search for the closest snapped grid line
+ Inkscape::SnappedLine closestGridLine;
+ if (getClosestSL(sc.grid_lines, closestGridLine)) {
+ sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
+ }
+
+ // search for the closest snapped guide line
+ Inkscape::SnappedLine closestGuideLine;
+ if (getClosestSL(sc.guide_lines, closestGuideLine)) {
+ sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
+ }
+
+ // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
+ // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
+
+ // When doing a constrained snap however, we're already at an intersection of the constrained line and
+ // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
+ // no need to look for additional intersections
+ if (!constrained) {
+ // search for the closest snapped intersection of grid lines
+ Inkscape::SnappedPoint closestGridPoint;
+ if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
+ sp_list.push_back(closestGridPoint);
+ }
+
+ // search for the closest snapped intersection of guide lines
+ Inkscape::SnappedPoint closestGuidePoint;
+ if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
+ sp_list.push_back(closestGuidePoint);
+ }
+
+ // search for the closest snapped intersection of grid with guide lines
+ if (_intersectionGG) {
+ Inkscape::SnappedPoint closestGridGuidePoint;
+ if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
+ sp_list.push_back(closestGridGuidePoint);
+ }
+ }
+ }
+
+ // now let's see which snapped point gets a thumbs up
+ Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
+ for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
+ // first find out if this snapped point is within snapping range
+ if ((*i).getDistance() <= (*i).getTolerance()) {
+ // if it's the first point
+ bool c1 = (i == sp_list.begin());
+ // or, if it's closer
+ bool c2 = (*i).getDistance() < bestSnappedPoint.getDistance();
+ // or, if it's for a snapper with "always snap" turned on, and the previous wasn't
+ bool c3 = (*i).getAlwaysSnap() && !bestSnappedPoint.getAlwaysSnap();
+ // But in no case fall back from a snapper with "always snap" on to one with "always snap" off
+ bool c3n = !(*i).getAlwaysSnap() && bestSnappedPoint.getAlwaysSnap();
+ // or, if it's just as close then consider the second distance
+ // (which is only relevant for points at an intersection)
+ bool c4a = ((*i).getDistance() == bestSnappedPoint.getDistance());
+ bool c4b = (*i).getSecondDistance() < bestSnappedPoint.getSecondDistance();
+ // then prefer this point over the previous one
+ if ((c1 || c2 || c3 || (c4a && c4b)) && !c3n) {
+ bestSnappedPoint = *i;
+ }
+ }
+ }
+
+ return bestSnappedPoint;
+}
+
/*
Local Variables:
mode:c++