snap.cpp revision d5dcb2202f14f34804d554fe37b2ebfd7b910769
#define __SP_DESKTOP_SNAP_C__
/**
* \file snap.cpp
* \brief SnapManager class.
*
* 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>
* Copyrigth (C) 2004 Nathan Hurst
* Copyright (C) 1999-2008 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 "snapped-curve.h"
#include <libnr/nr-point-fns.h>
#include <libnr/nr-scale-ops.h>
#include <libnr/nr-values.h>
#include "display/canvas-grid.h"
#include "display/snap-indicator.h"
#include "inkscape.h"
#include "desktop.h"
#include "sp-guide.h"
using std::vector;
/**
* Construct a SnapManager for a SPNamedView.
*
* \param v `Owning' SPNamedView.
*/
SnapManager::SnapManager(SPNamedView const *v) :
guide(v, 0),
object(v, 0),
_named_view(v),
_include_item_center(false),
_snap_enabled_globally(true)
{
}
/**
* \return List of snappers that we use.
*/
SnapManager::SnapperList
SnapManager::getSnappers() const
{
SnapManager::SnapperList s;
s.push_back(&guide);
s.push_back(&object);
SnapManager::SnapperList gs = getGridSnappers();
s.splice(s.begin(), gs);
return s;
}
/**
* \return List of gridsnappers that we use.
*/
SnapManager::SnapperList
SnapManager::getGridSnappers() const
{
SnapperList s;
//FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
SPDesktop* desktop = SP_ACTIVE_DESKTOP;
if (desktop && desktop->gridsEnabled()) {
for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
s.push_back(grid->snapper);
}
}
return s;
}
/**
* \return true if one of the snappers will try to snap something.
*/
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)
{
//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);
}
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::setSnapModeGuide(bool enabled)
{
object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_GUIDE, enabled);
}
bool SnapManager::getSnapModeGuide() const
{
return object.getSnapFrom(Inkscape::Snapper::SNAPPOINT_GUIDE);
}
/**
* Try to snap a point to any of the specified snappers.
*
* \param point_type 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 snappers List of snappers to try to snap to
* \return Snapped point.
*/
void SnapManager::freeSnapReturnByRef(Inkscape::Snapper::PointType point_type,
Geom::Point &p,
bool first_point,
boost::optional<Geom::Rect> const &bbox_to_snap) const
{
Inkscape::SnappedPoint const s = freeSnap(point_type, p, first_point, bbox_to_snap);
s.getPoint(p);
}
/**
* Try to snap a point to any of the specified snappers.
*
* \param point_type 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 snappers List of snappers to try to snap to
* \return Snapped point.
*/
Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::Snapper::PointType point_type,
Geom::Point const &p,
bool first_point,
boost::optional<Geom::Rect> const &bbox_to_snap) const
{
if (!SomeSnapperMightSnap()) {
return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false);
}
std::vector<SPItem const *> *items_to_ignore;
if (_item_to_ignore) { // If we have only a single item to ignore
// then build a list containing this single item;
// This single-item list will prevail over any other _items_to_ignore list, should that exist
items_to_ignore = new std::vector<SPItem const *>;
items_to_ignore->push_back(_item_to_ignore);
} else {
items_to_ignore = _items_to_ignore;
}
SnappedConstraints sc;
SnapperList const snappers = getSnappers();
for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
(*i)->freeSnap(sc, point_type, p, first_point, bbox_to_snap, items_to_ignore, _unselected_nodes);
}
if (_item_to_ignore) {
delete items_to_ignore;
}
return findBestSnap(p, sc, false);
}
// When pasting, we would like to snap to the grid. Problem is that we don't know which nodes were
// aligned to the grid at the time of copying, so we don't know which nodes to snap. If we'd snap an
// unaligned node to the grid, previously aligned nodes would become unaligned. That's undesirable.
// Instead we will make sure that the offset between the source and the copy is a multiple of the grid
// pitch. If the source was aligned, then the copy will therefore also be aligned
// PS: Wether we really find a multiple also depends on the snapping range!
Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t) const
{
if (!_snap_enabled_globally)
return t;
//FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
SPDesktop* desktop = SP_ACTIVE_DESKTOP;
if (desktop && desktop->gridsEnabled()) {
bool success = false;
Geom::Point nearest_multiple;
Geom::Coord nearest_distance = NR_HUGE;
// It will snap to the grid for which we find the closest snap. This might be a different
// grid than to which the objects were initially aligned. I don't see an easy way to fix
// this, so when using multiple grids one can get unexpected results
// Cannot use getGridSnappers() because we need both the grids AND their snappers
// Therefor we iterate through all grids manually
for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
const Inkscape::Snapper* snapper = grid->snapper;
if (snapper && snapper->ThisSnapperMightSnap()) {
// To find the nearest multiple of the grid pitch for a given translation t, we
// will use the grid snapper. Simply snapping the value t to the grid will do, but
// only if the origin of the grid is at (0,0). If it's not then compensate for this
// in the translation t
Geom::Point const t_offset = from_2geom(t) + grid->origin;
SnappedConstraints sc;
// Only the first three parameters are being used for grid snappers
snapper->freeSnap(sc, Inkscape::Snapper::SNAPPOINT_NODE, t_offset, TRUE, boost::optional<Geom::Rect>(), NULL, NULL);
// Find the best snap for this grid, including intersections of the grid-lines
Inkscape::SnappedPoint s = findBestSnap(t_offset, sc, false);
if (s.getSnapped() && (s.getDistance() < nearest_distance)) {
success = true;
nearest_multiple = s.getPoint() - to_2geom(grid->origin);
nearest_distance = s.getDistance();
}
}
}
if (success)
return nearest_multiple;
}
return t;
}
/**
* Try to snap a point to any interested snappers. A snap will only occur along
* a line described by a Inkscape::Snapper::ConstraintLine.
*
* \param point_type 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 constraint Constraint line.
* \return Snapped point.
*/
void SnapManager::constrainedSnapReturnByRef(Inkscape::Snapper::PointType point_type,
Geom::Point &p,
Inkscape::Snapper::ConstraintLine const &constraint,
bool first_point,
boost::optional<Geom::Rect> const &bbox_to_snap) const
{
Inkscape::SnappedPoint const s = constrainedSnap(point_type, p, constraint, first_point, bbox_to_snap);
s.getPoint(p);
}
/**
* Try to snap a point to any interested snappers. A snap will only occur along
* a line described by a Inkscape::Snapper::ConstraintLine.
*
* \param point_type 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 constraint Constraint line.
* \return Snapped point.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType point_type,
Geom::Point const &p,
Inkscape::Snapper::ConstraintLine const &constraint,
bool first_point,
boost::optional<Geom::Rect> const &bbox_to_snap) const
{
if (!SomeSnapperMightSnap()) {
return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false);
}
std::vector<SPItem const *> *items_to_ignore;
if (_item_to_ignore) { // If we have only a single item to ignore
// then build a list containing this single item;
// This single-item list will prevail over any other _items_to_ignore list, should that exist
items_to_ignore = new std::vector<SPItem const *>;
items_to_ignore->push_back(_item_to_ignore);
} else {
items_to_ignore = _items_to_ignore;
}
SnappedConstraints sc;
SnapperList const snappers = getSnappers();
for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
(*i)->constrainedSnap(sc, point_type, p, first_point, bbox_to_snap, constraint, items_to_ignore);
}
if (_item_to_ignore) {
delete items_to_ignore;
}
return findBestSnap(p, sc, true);
}
void SnapManager::guideSnap(Geom::Point &p, Geom::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;
}
SnappedConstraints sc;
object.guideSnap(sc, p, guide_normal);
Inkscape::SnappedPoint const s = findBestSnap(p, sc, false);
s.getPoint(p);
}
/**
* Main internal snapping method, which is called by the other, friendlier, public
* methods. It's a bit hairy as it has lots of parameters, but it saves on a lot
* of duplicated code.
*
* \param type Type of points being snapped.
* \param points List of points to snap.
* \param constrained true if the snap is constrained.
* \param constraint Constraint line to use, if `constrained' is true, otherwise undefined.
* \param transformation_type Type of transformation to apply to points before trying to snap them.
* \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; only applicable for stretching and scaling.
*/
Inkscape::SnappedPoint SnapManager::_snapTransformed(
Inkscape::Snapper::PointType type,
std::vector<Geom::Point> const &points,
bool constrained,
Inkscape::Snapper::ConstraintLine const &constraint,
Transformation transformation_type,
Geom::Point const &transformation,
Geom::Point const &origin,
Geom::Dim2 dim,
bool uniform) const
{
/* We have a list of points, which we are proposing to transform in some way. We need to see
** if any of these points, when transformed, snap to anything. If they do, we return the
** appropriate transformation with `true'; otherwise we return the original scale with `false'.
*/
/* Quick check to see if we have any snappers that are enabled
** Also used to globally disable all snapping
*/
if (SomeSnapperMightSnap() == false) {
g_assert(points.size() > 0);
return Inkscape::SnappedPoint();
}
std::vector<Geom::Point> transformed_points;
Geom::Rect bbox;
for (std::vector<Geom::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
/* Work out the transformed version of this point */
Geom::Point transformed;
switch (transformation_type) {
case TRANSLATION:
transformed = *i + transformation;
break;
case SCALE:
transformed = (*i - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
break;
case STRETCH:
{
Geom::Scale s(1, 1);
if (uniform)
s[Geom::X] = s[Geom::Y] = transformation[dim];
else {
s[dim] = transformation[dim];
s[1 - dim] = 1;
}
transformed = ((*i - origin) * s) + origin;
break;
}
case SKEW:
// Apply the skew factor
transformed[dim] = (*i)[dim] + transformation[0] * ((*i)[1 - dim] - origin[1 - dim]);
// While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
// Apply that scale factor here
transformed[1-dim] = (*i - origin)[1 - dim] * transformation[1] + origin[1 - dim];
break;
default:
g_assert_not_reached();
}
// add the current transformed point to the box hulling all transformed points
if (i == points.begin()) {
bbox = Geom::Rect(transformed, transformed);
} else {
bbox.expandTo(transformed);
}
transformed_points.push_back(transformed);
}
/* The current best transformation */
Geom::Point best_transformation = transformation;
/* The current best metric for the best transformation; lower is better, NR_HUGE
** means that we haven't snapped anything.
*/
Geom::Coord best_metric = NR_HUGE;
Geom::Coord best_second_metric = NR_HUGE;
Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
Inkscape::SnappedPoint best_snapped_point;
g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
g_assert(best_snapped_point.getAtIntersection() == false);
std::vector<Geom::Point>::const_iterator j = transformed_points.begin();
// std::cout << std::endl;
for (std::vector<Geom::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
/* Snap it */
Inkscape::SnappedPoint snapped_point;
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) { // when non-uniform stretching {
dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i), component_vectors[dim]);
} else if (transformation_type == TRANSLATION) {
// When doing a constrained translation, all points will move in the same direction, i.e.
// either horizontally or vertically. The lines along which they move are therefore all
// parallel, but might not be colinear. Therefore we will have to set the point through
// which the constraint-line runs here, for each point individually.
dedicated_constraint.setPoint(*i);
} // else: leave the original constraint, e.g. for skewing
if (transformation_type == SCALE && !uniform) {
g_warning("Non-uniform constrained scaling is not supported!");
}
snapped_point = constrainedSnap(type, *j, dedicated_constraint, i == points.begin(), bbox);
} else {
snapped_point = freeSnap(type, *j, i == points.begin(), bbox);
}
Geom::Point result;
Geom::Coord metric = NR_HUGE;
Geom::Coord second_metric = NR_HUGE;
Geom::Point scale_metric(NR_HUGE, NR_HUGE);
if (snapped_point.getSnapped()) {
/* We snapped. Find the transformation that describes where the snapped point has
** ended up, and also the metric for this transformation.
*/
Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
Geom::Point const b = (*i - origin); // vector to original point
switch (transformation_type) {
case TRANSLATION:
result = snapped_point.getPoint() - *i;
/* 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 = Geom::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_point.getDistance(); //used to be: metric = Geom::L2(result);
second_metric = snapped_point.getSecondDistance();
break;
case SCALE:
{
result = Geom::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:
result = Geom::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[0] = (snapped_point.getPoint()[dim] - (*i)[dim]) / ((*i)[1 - dim] - origin[1 - dim]); // skew factor
result[1] = transformation[1]; // scale factor
metric = std::abs(result[0] - transformation[0]);
break;
default:
g_assert_not_reached();
}
/* Note it if it's the best so far */
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]);
// When scaling, we're considering the best transformation in each direction separately
// Therefore two different snapped points might together make a single best transformation
// We will however return only a single snapped point (e.g. to display the snapping indicator)
best_snapped_point = snapped_point;
// 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_point.getDistance() << " | P_snap = " << snapped_point.getPoint() << std::endl;
} else {
bool const c1 = metric < best_metric;
bool const c2 = metric == best_metric && snapped_point.getAtIntersection() == true && best_snapped_point.getAtIntersection() == false;
bool const c3a = metric == best_metric && snapped_point.getAtIntersection() == true && best_snapped_point.getAtIntersection() == true;
bool const c3b = second_metric < best_second_metric;
bool const c4 = snapped_point.getAlwaysSnap() == true && best_snapped_point.getAlwaysSnap() == false;
bool const c4n = snapped_point.getAlwaysSnap() == false && best_snapped_point.getAlwaysSnap() == true;
if ((c1 || c2 || (c3a && c3b) || c4) && !c4n) {
best_transformation = result;
best_metric = metric;
best_second_metric = second_metric;
best_snapped_point = snapped_point;
// std::cout << "SEL ";
} // else { std::cout << " ";}
// std::cout << "P_orig = " << (*i) << " | metric = " << metric << " | distance = " << snapped_point.getDistance() << " | second metric = " << second_metric << " | P_snap = " << snapped_point.getPoint() << std::endl;
}
}
j++;
}
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];
}
}
}
}
best_snapped_point.setTransformation(best_transformation);
// Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
// These rounding errors might be caused by NRRects, see bug #1584301
best_snapped_point.setDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
return best_snapped_point;
}
/**
* Try to snap a list of points to any interested snappers after they have undergone
* a translation.
*
* \param point_type Type of points.
* \param p Points.
* \param tr Proposed translation.
* \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
*/
Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::Snapper::PointType point_type,
std::vector<Geom::Point> const &p,
Geom::Point const &tr) const
{
return _snapTransformed(point_type, p, false, Geom::Point(), TRANSLATION, tr, Geom::Point(), Geom::X, false);
}
/**
* Try to snap a list of points to any interested snappers after they have undergone a
* translation. A snap will only occur along a line described by a
* Inkscape::Snapper::ConstraintLine.
*
* \param point_type Type of points.
* \param p Points.
* \param constraint Constraint line.
* \param tr Proposed translation.
* \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::Snapper::PointType point_type,
std::vector<Geom::Point> const &p,
Inkscape::Snapper::ConstraintLine const &constraint,
Geom::Point const &tr) const
{
return _snapTransformed(point_type, p, true, constraint, TRANSLATION, tr, Geom::Point(), Geom::X, false);
}
/**
* Try to snap a list of points to any interested snappers after they have undergone
* a scale.
*
* \param point_type Type of points.
* \param p Points.
* \param s Proposed scale.
* \param o Origin of proposed scale.
* \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
*/
Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::Snapper::PointType point_type,
std::vector<Geom::Point> const &p,
Geom::Scale const &s,
Geom::Point const &o) const
{
return _snapTransformed(point_type, p, false, Geom::Point(), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
}
/**
* Try to snap a list of points to any interested snappers after they have undergone
* a scale. A snap will only occur along a line described by a
* Inkscape::Snapper::ConstraintLine.
*
* \param point_type Type of points.
* \param p Points.
* \param s Proposed scale.
* \param o Origin of proposed scale.
* \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapScale(Inkscape::Snapper::PointType point_type,
std::vector<Geom::Point> const &p,
Geom::Scale const &s,
Geom::Point const &o) const
{
// When constrained scaling, only uniform scaling is supported.
return _snapTransformed(point_type, p, true, Geom::Point(), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
}
/**
* Try to snap a list of points to any interested snappers after they have undergone
* a stretch.
*
* \param point_type Type of points.
* \param p Points.
* \param s Proposed stretch.
* \param o Origin of proposed stretch.
* \param d Dimension in which to apply proposed stretch.
* \param u true if the stretch should be uniform (ie to be applied equally in both dimensions)
* \return Snapped stretch, if a snap occurred, and a flag indicating whether a snap occurred.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::Snapper::PointType point_type,
std::vector<Geom::Point> const &p,
Geom::Coord const &s,
Geom::Point const &o,
Geom::Dim2 d,
bool u) const
{
return _snapTransformed(point_type, p, true, Geom::Point(), STRETCH, Geom::Point(s, s), o, d, u);
}
/**
* Try to snap a list of points to any interested snappers after they have undergone
* a skew.
*
* \param point_type Type of points.
* \param p Points.
* \param s Proposed skew.
* \param o Origin of proposed skew.
* \param d Dimension in which to apply proposed skew.
* \return Snapped skew, if a snap occurred, and a flag indicating whether a snap occurred.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::Snapper::PointType point_type,
std::vector<Geom::Point> const &p,
Inkscape::Snapper::ConstraintLine const &constraint,
Geom::Point const &s,
Geom::Point const &o,
Geom::Dim2 d) const
{
// "s" contains skew factor in s[0], and scale factor in s[1]
return _snapTransformed(point_type, p, true, constraint, SKEW, s, o, d, false);
}
Inkscape::SnappedPoint SnapManager::findBestSnap(Geom::Point const &p, SnappedConstraints &sc, bool constrained) const
{
/*
std::cout << "Type and number of snapped constraints: " << std::endl;
std::cout << " Points : " << sc.points.size() << std::endl;
std::cout << " Lines : " << sc.lines.size() << std::endl;
std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
*/
// 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 curve
Inkscape::SnappedCurve closestCurve;
if (getClosestCurve(sc.curves, closestCurve)) {
sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
}
if (_intersectionCS) {
// search for the closest snapped intersection of curves
Inkscape::SnappedPoint closestCurvesIntersection;
if (getClosestIntersectionCS(sc.curves, p, closestCurvesIntersection)) {
sp_list.push_back(closestCurvesIntersection);
}
}
// search for the closest snapped grid line
Inkscape::SnappedLine closestGridLine;
if (getClosestSL(sc.grid_lines, closestGridLine)) {
closestGridLine.setTarget(Inkscape::SNAPTARGET_GRID);
sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
}
// search for the closest snapped guide line
Inkscape::SnappedLine closestGuideLine;
if (getClosestSL(sc.guide_lines, closestGuideLine)) {
closestGuideLine.setTarget(Inkscape::SNAPTARGET_GUIDE);
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)) {
closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
sp_list.push_back(closestGridPoint);
}
// search for the closest snapped intersection of guide lines
Inkscape::SnappedPoint closestGuidePoint;
if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
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)) {
closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
sp_list.push_back(closestGridGuidePoint);
}
}
}
// now let's see which snapped point gets a thumbs up
Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, 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;
}
}
}
// Update the snap indicator, if requested
if (_snapindicator) {
if (bestSnappedPoint.getSnapped()) {
_desktop->snapindicator->set_new_snappoint(bestSnappedPoint);
} else {
_desktop->snapindicator->remove_snappoint();
}
}
// std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << std::endl;
return bestSnappedPoint;
}
void SnapManager::setup(SPDesktop const *desktop, bool snapindicator, SPItem const *item_to_ignore, std::vector<Geom::Point> *unselected_nodes)
{
g_assert(desktop != NULL);
object.setDesktop(desktop);
_item_to_ignore = item_to_ignore;
_items_to_ignore = NULL;
_desktop = desktop;
_snapindicator = snapindicator;
_unselected_nodes = unselected_nodes;
}
void SnapManager::setup(SPDesktop const *desktop, bool snapindicator, std::vector<SPItem const *> &items_to_ignore, std::vector<Geom::Point> *unselected_nodes)
{
g_assert(desktop != NULL);
object.setDesktop(desktop);
_item_to_ignore = NULL;
_items_to_ignore = &items_to_ignore;
_desktop = desktop;
_snapindicator = snapindicator;
_unselected_nodes = unselected_nodes;
}
/*
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:encoding=utf-8:textwidth=99 :