object-snapper.cpp revision aee6bba4d090adbd7801efd2eb156ca8aee2301f
/**
* \file object-snapper.cpp
* \brief Snapping things to objects.
*
* Authors:
* Carl Hetherington <inkscape@carlh.net>
* Diederik van Lierop <mail@diedenrezi.nl>
*
* Copyright (C) 2005 - 2008 Authors
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#include "svg/svg.h"
#include "libnr/nr-path.h"
#include "libnr/nr-rect-ops.h"
#include "libnr/nr-point-fns.h"
#include <2geom/path-intersection.h>
#include <2geom/point.h>
#include <2geom/rect.h>
#include "document.h"
#include "sp-namedview.h"
#include "sp-image.h"
#include "sp-item-group.h"
#include "sp-item.h"
#include "sp-use.h"
#include "display/curve.h"
#include "desktop.h"
#include "inkscape.h"
#include "prefs-utils.h"
#include "sp-text.h"
#include "sp-flowtext.h"
#include "text-editing.h"
#include "sp-clippath.h"
#include "sp-mask.h"
#include "helper/geom-curves.h"
Inkscape::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, NR::Matrix additional_affine)
: item(item), clip_or_mask(clip_or_mask), additional_affine(additional_affine)
{
}
Inkscape::SnapCandidate::~SnapCandidate()
{
}
Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, NR::Coord const d)
: Snapper(nv, d), _snap_to_itemnode(true), _snap_to_itempath(true),
_snap_to_bboxnode(true), _snap_to_bboxpath(true), _snap_to_page_border(false),
_strict_snapping(true), _include_item_center(false)
{
_candidates = new std::vector<SnapCandidate>;
_points_to_snap_to = new std::vector<NR::Point>;
_paths_to_snap_to = new std::vector<Geom::PathVector*>;
}
Inkscape::ObjectSnapper::~ObjectSnapper()
{
_candidates->clear();
delete _candidates;
_points_to_snap_to->clear();
delete _points_to_snap_to;
_clear_paths();
delete _paths_to_snap_to;
}
/**
* Find all items within snapping range.
* \param parent Pointer to the document's root, or to a clipped path or mask object
* \param it List of items to ignore
* \param first_point If true then this point is the first one from a whole bunch of points
* \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
* \param DimensionToSnap Snap in X, Y, or both directions.
*/
void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
std::vector<SPItem const *> const *it,
bool const &first_point,
NR::Rect const &bbox_to_snap,
DimensionToSnap const snap_dim,
bool const clip_or_mask,
NR::Matrix const additional_affine) const // transformation of the item being clipped / masked
{
bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
if (!(c1 || c2)) {
return;
}
SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
if (first_point) {
_candidates->clear();
}
boost::optional<NR::Rect> bbox_of_item = NR::Rect(); // a default NR::Rect is infinitely large
NR::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
bbox_to_snap_incl.growBy(getSnapperTolerance()); // see?
for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !(desktop->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
// Don't snap to locked items, and
// don't snap to hidden objects, unless they're a clipped path or a mask
/* See if this item is on the ignore list */
std::vector<SPItem const *>::const_iterator i;
if (it != NULL) {
i = it->begin();
while (i != it->end() && *i != o) {
i++;
}
}
if (it == NULL || i == it->end()) {
SPItem *item = SP_ITEM(o);
NR::Matrix transform = NR::identity();
if (item) {
SPObject *obj = NULL;
if (clip_or_mask) { // If the current item is a clipping path or a mask
// then store the transformation of the clipped path or mask itself
// but also take into account the additional affine of the object
// being clipped / masked
transform = item->transform * additional_affine;
} else { // cannot clip or mask more than once
// The current item is not a clipping path or a mask, but might
// still be the subject of clipping or masking itself ; if so, then
// we should also consider that path or mask for snapping to
obj = SP_OBJECT(item->clip_ref->getObject());
if (obj) {
_findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
}
obj = SP_OBJECT(item->mask_ref->getObject());
if (obj) {
_findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
}
}
}
if (SP_IS_GROUP(o)) {
_findCandidates(o, it, false, bbox_to_snap, snap_dim, false, NR::identity());
} else {
if (clip_or_mask) {
// Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
// insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
sp_item_invoke_bbox(item,
&bbox_of_item,
sp_item_i2doc_affine(item) * matrix_to_desktop(additional_affine, item),
true);
} else {
sp_item_invoke_bbox(item, &bbox_of_item, sp_item_i2d_affine(item), true);
}
// See if the item is within range
if (bbox_of_item) {
if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
// This item is within snapping range, so record it as a candidate
_candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
}
}
}
}
}
}
}
void Inkscape::ObjectSnapper::_collectNodes(Inkscape::Snapper::PointType const &t,
bool const &first_point) const
{
// Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
// e.g. when translating an item using the selector tool, then we will only do this for the
// first point and store the collection for later use. This significantly improves the performance
if (first_point) {
_points_to_snap_to->clear();
// Determine the type of bounding box we should snap to
SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
bool p_is_a_bbox = t & Inkscape::Snapper::SNAPPOINT_BBOX;
bool p_is_a_guide = t & Inkscape::Snapper::SNAPPOINT_GUIDE;
// A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
g_assert(!(p_is_a_node && p_is_a_bbox || p_is_a_bbox && p_is_a_guide || p_is_a_node && p_is_a_guide));
if (_snap_to_bboxnode) {
int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
bbox_type = (prefs_bbox == 0)?
SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
}
// Consider the page border for snapping
if (_snap_to_page_border) {
_getBorderNodes(_points_to_snap_to);
}
for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
//NR::Matrix i2doc(NR::identity());
SPItem *root_item = (*i).item;
if (SP_IS_USE((*i).item)) {
root_item = sp_use_root(SP_USE((*i).item));
}
g_return_if_fail(root_item);
//Collect all nodes so we can snap to them
if (_snap_to_itemnode) {
if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
sp_item_snappoints(root_item, _include_item_center, SnapPointsIter(*_points_to_snap_to));
}
}
//Collect the bounding box's corners so we can snap to them
if (_snap_to_bboxnode) {
if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
// Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
// of the item AND the bbox of the clipping path at the same time
if (!(*i).clip_or_mask) {
boost::optional<NR::Rect> b = sp_item_bbox_desktop(root_item, bbox_type);
if (b) {
for ( unsigned k = 0 ; k < 4 ; k++ ) {
_points_to_snap_to->push_back(b->corner(k));
}
}
}
}
}
}
}
}
void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
Inkscape::Snapper::PointType const &t,
NR::Point const &p,
bool const &first_point,
std::vector<NR::Point> *unselected_nodes) const
{
// Iterate through all nodes, find out which one is the closest to p, and snap to it!
_collectNodes(t, first_point);
if (unselected_nodes != NULL) {
_points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
}
SnappedPoint s;
bool success = false;
for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
NR::Coord dist = NR::L2(*k - p);
if (dist < getSnapperTolerance() && dist < s.getDistance()) {
s = SnappedPoint(*k, SNAPTARGET_NODE, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
success = true;
}
}
if (success) {
sc.points.push_back(s);
}
}
void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
Inkscape::Snapper::PointType const &t,
NR::Point const &p,
NR::Point const &guide_normal) const
{
// Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
_collectNodes(t, true);
SnappedPoint s;
bool success = false;
NR::Coord tol = getSnapperTolerance();
for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
// Project each node (*k) on the guide line (running through point p)
NR::Point p_proj = project_on_linesegment(*k, p, p + NR::rot90(guide_normal));
NR::Coord dist = NR::L2(*k - p_proj); // distance from node to the guide
NR::Coord dist2 = NR::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
if ((dist < tol && dist2 < tol || getSnapperAlwaysSnap()) && dist < s.getDistance()) {
s = SnappedPoint(*k, SNAPTARGET_NODE, dist, tol, getSnapperAlwaysSnap());
success = true;
}
}
if (success) {
sc.points.push_back(s);
}
}
/**
* Returns index of first NR_END bpath in array.
*/
/* Obsolete
static unsigned sp_bpath_length(NArtBpath const bpath[])
{
g_return_val_if_fail(bpath != NULL, FALSE);
unsigned ret = 0;
while ( bpath[ret].code != NR_END ) {
++ret;
}
++ret;
return ret;
}*/
void Inkscape::ObjectSnapper::_collectPaths(Inkscape::Snapper::PointType const &t,
bool const &first_point) const
{
// Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
// e.g. when translating an item using the selector tool, then we will only do this for the
// first point and store the collection for later use. This significantly improves the performance
if (first_point) {
_clear_paths();
// Determine the type of bounding box we should snap to
SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
if (_snap_to_bboxpath) {
int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
bbox_type = (prefs_bbox ==0)?
SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
}
// Consider the page border for snapping
if (_snap_to_page_border) {
Geom::PathVector *border_path = _getBorderPathv();
if (border_path != NULL) {
_paths_to_snap_to->push_back(border_path);
}
}
for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
/* Transform the requested snap point to this item's coordinates */
NR::Matrix i2doc(NR::identity());
SPItem *root_item = NULL;
/* We might have a clone at hand, so make sure we get the root item */
if (SP_IS_USE((*i).item)) {
i2doc = sp_use_get_root_transform(SP_USE((*i).item));
root_item = sp_use_root(SP_USE((*i).item));
g_return_if_fail(root_item);
} else {
i2doc = sp_item_i2doc_affine((*i).item);
root_item = (*i).item;
}
//Build a list of all paths considered for snapping to
//Add the item's path to snap to
if (_snap_to_itempath) {
if (!(_strict_snapping && !p_is_a_node)) {
// Snapping to the path of characters is very cool, but for a large
// chunk of text this will take ages! So limit snapping to text paths
// containing max. 240 characters. Snapping the bbox will not be affected
bool very_lenghty_prose = false;
if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
}
// On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
// which corresponds to a lag of 500 msec. This is for snapping a rect
// to a single line of text.
// Snapping for example to a traced bitmap is also very stressing for
// the CPU, so we'll only snap to paths having no more than 500 nodes
// This also leads to a lag of approx. 500 msec (in my lousy test set-up).
bool very_complex_path = false;
if (SP_IS_PATH(root_item)) {
very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
}
if (!very_lenghty_prose && !very_complex_path) {
SPCurve *curve = curve_for_item(root_item);
if (curve) {
// We will get our own copy of the path, which must be freed at some point
Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
_paths_to_snap_to->push_back(borderpathv); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
curve->unref();
}
}
}
}
//Add the item's bounding box to snap to
if (_snap_to_bboxpath) {
if (!(_strict_snapping && p_is_a_node)) {
// Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
// of the item AND the bbox of the clipping path at the same time
if (!(*i).clip_or_mask) {
NRRect rect;
sp_item_invoke_bbox(root_item, &rect, i2doc, TRUE, bbox_type);
Geom::Rect const rect2 = to_2geom(*rect.upgrade());
Geom::PathVector *path = _getPathvFromRect(rect2);
_paths_to_snap_to->push_back(path);
}
}
}
}
}
}
void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
Inkscape::Snapper::PointType const &t,
NR::Point const &p,
bool const &first_point,
std::vector<NR::Point> *unselected_nodes,
SPPath const *selected_path) const
{
_collectPaths(t, first_point);
// Now we can finally do the real snapping, using the paths collected above
/* FIXME: this seems like a hack. Perhaps Snappers should be
** in SPDesktop rather than SPNamedView?
*/
// TODO Diederik: shouldn't we just make all snapping code use document
// coordinates instead? Then we won't need a pointer to the desktop any longer
// At least we should define a clear boundary between those different coordinates,
// now this is not well defined
SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
Geom::Point const p_doc = desktop->dt2doc(p);
bool const node_tool_active = _snap_to_itempath && selected_path != NULL;
if (first_point) {
/* While editing a path in the node tool, findCandidates must ignore that path because
* of the node snapping requirements (i.e. only unselected nodes must be snapable).
* This path must not be ignored however when snapping to the paths, so we add it here
* manually when applicable.
*
* Note that this path must be the last in line!
* */
if (node_tool_active) {
SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
if (curve) {
Geom::PathVector *pathv = pathvector_for_curve(SP_ITEM(selected_path), curve, true, true, Geom::identity(), Geom::identity()); // We will get our own copy of the path, which must be freed at some point
_paths_to_snap_to->push_back(pathv);
curve->unref();
}
}
}
for (std::vector<Geom::PathVector*>::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
//if true then this pathvector it_pv is currently being edited in the node tool
// char * svgd = sp_svg_write_path(**it_p);
// std::cout << "Dumping the pathvector: " << svgd << std::endl;
for(Geom::PathVector::iterator it_pv = (*it_p)->begin(); it_pv != (*it_p)->end(); ++it_pv) {
std::vector<double> anp;
// Find a nearest point for each curve within this path
// (path->allNearestPoints() will not do this for us! It was originally
// intended to find for example multiple equidistant solutions)
unsigned int num_curves = (*it_pv).size();
if ( (*it_pv).closed() ) ++num_curves;
for (double t = 0; (t+1) <= double(num_curves); t++) {
// Find a nearest point with time value in the range [t, t+1]
anp.push_back((*it_pv).nearestPoint(p_doc, t, t+1));
}
for (std::vector<double>::const_iterator np = anp.begin(); np != anp.end(); np++) {
bool c1 = true;
bool c2 = true;
Geom::Point start_pt = desktop->doc2dt((*it_pv).pointAt(floor(*np)));
Geom::Point end_pt = desktop->doc2dt((*it_pv).pointAt(ceil(*np)));
if (being_edited) {
/* If the path is being edited, then we should only snap though to stationary pieces of the path
* and not to the pieces that are being dragged around. This way we avoid
* self-snapping. For this we check whether the nodes at both ends of the current
* piece are unselected; if they are then this piece must be stationary
*/
g_assert(unselected_nodes != NULL);
c1 = isUnselectedNode(start_pt, unselected_nodes);
c2 = isUnselectedNode(end_pt, unselected_nodes);
}
Geom::Point const sp_doc = (*it_pv).pointAt(*np);
Geom::Point const sp_dt = desktop->doc2dt(sp_doc);
if (!being_edited || (c1 && c2)) {
NR::Coord const dist = Geom::distance(sp_doc, p_doc);
if (dist < getSnapperTolerance()) {
double t = MIN(*np, (*it_pv).size()); // make sure that t is within bounds;
Geom::Curve const *curve = &((*it_pv).at_index(int(t)));
sc.curves.push_back(Inkscape::SnappedCurve(from_2geom(sp_dt), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), curve));
}
}
}
} // End of: for (Geom::PathVector::iterator ....)
}
}
/* Returns true if point is coincident with one of the unselected nodes */
bool Inkscape::ObjectSnapper::isUnselectedNode(NR::Point const &point, std::vector<NR::Point> const *unselected_nodes) const
{
if (unselected_nodes == NULL) {
return false;
}
if (unselected_nodes->size() == 0) {
return false;
}
for (std::vector<NR::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
if (NR::L2(point - *i) < 1e-4) {
return true;
}
}
return false;
}
void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
Inkscape::Snapper::PointType const &t,
NR::Point const &p,
bool const &first_point,
ConstraintLine const &c) const
{
_collectPaths(t, first_point);
// Now we can finally do the real snapping, using the paths collected above
/* FIXME: this seems like a hack. Perhaps Snappers should be
** in SPDesktop rather than SPNamedView?
*/
SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
NR::Point const p_doc = desktop->dt2doc(p);
NR::Point direction_vector = c.getDirection();
if (!is_zero(direction_vector)) {
direction_vector = NR::unit_vector(direction_vector);
}
NR::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
NR::Point const p2_on_cl = p1_on_cl + direction_vector;
// The intersection point of the constraint line with any path,
// must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
// The distance between those points is twice the snapping tolerance
NR::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
NR::Point const p_min_on_cl = desktop->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
NR::Point const p_max_on_cl = desktop->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
Geom::Path cl;
std::vector<Geom::Path> clv;
cl.start(p_min_on_cl);
cl.appendNew<Geom::LineSegment>(p_max_on_cl);
clv.push_back(cl);
for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
if (*k) {
Geom::CrossingSet cs = Geom::crossings(clv, *(*k));
if (cs.size() > 0) {
// We need only the first element of cs, because cl is only a single straight linesegment
// This first element contains a vector filled with crossings of cl with *k
for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
if ((*m).ta >= 0 && (*m).ta <= 1 ) {
// Reconstruct the point of intersection
NR::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
// When it's within snapping range, then return it
// (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
NR::Coord dist = NR::L2(desktop->dt2doc(p_proj_on_cl) - p_inters);
SnappedPoint s(desktop->doc2dt(p_inters), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
sc.points.push_back(s);
}
}
}
}
}
}
void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
Inkscape::Snapper::PointType const &t,
NR::Point const &p,
bool const &first_point,
boost::optional<NR::Rect> const &bbox_to_snap,
std::vector<SPItem const *> const *it,
std::vector<NR::Point> *unselected_nodes) const
{
if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
return;
}
/* Get a list of all the SPItems that we will try to snap to */
if (first_point) {
NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
_findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, NR::identity());
}
if (_snap_to_itemnode || _snap_to_bboxnode || _snap_to_page_border) {
_snapNodes(sc, t, p, first_point, unselected_nodes);
}
if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
if (n > 0) {
/* While editing a path in the node tool, findCandidates must ignore that path because
* of the node snapping requirements (i.e. only unselected nodes must be snapable).
* That path must not be ignored however when snapping to the paths, so we add it here
* manually when applicable
*/
SPPath *path = NULL;
if (it != NULL) {
g_assert(SP_IS_PATH(*it->begin()));
g_assert(it->size() == 1);
path = SP_PATH(*it->begin());
}
_snapPaths(sc, t, p, first_point, unselected_nodes, path);
} else {
_snapPaths(sc, t, p, first_point, NULL, NULL);
}
}
}
void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
Inkscape::Snapper::PointType const &t,
NR::Point const &p,
bool const &first_point,
boost::optional<NR::Rect> const &bbox_to_snap,
ConstraintLine const &c,
std::vector<SPItem const *> const *it) const
{
if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
return;
}
/* Get a list of all the SPItems that we will try to snap to */
if (first_point) {
NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
_findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, NR::identity());
}
// A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
// This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
// nodes are only allowed to move in one direction (i.e. in one degree of freedom).
// When snapping to objects, we either snap to their nodes or their paths. It is however very
// unlikely that any node will be exactly at the constrained line, so for a constrained snap
// to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
// so we will more or less snap to them anyhow.
if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
_snapPathsConstrained(sc, t, p, first_point, c);
}
}
// This method is used to snap a guide to nodes, while dragging the guide around
void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
NR::Point const &p,
NR::Point const &guide_normal) const
{
if ( NULL == _named_view ) {
return;
}
/* Get a list of all the SPItems that we will try to snap to */
std::vector<SPItem*> cand;
std::vector<SPItem const *> const it; //just an empty list
DimensionToSnap snap_dim;
if (guide_normal == component_vectors[NR::Y]) {
snap_dim = GUIDE_TRANSL_SNAP_Y;
} else if (guide_normal == component_vectors[NR::X]) {
snap_dim = GUIDE_TRANSL_SNAP_X;
} else {
snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
}
// We don't support ANGLED_GUIDE_ROT_SNAP yet.
// It would be cool to allow the user to rotate a guide by dragging it, instead of
// only translating it. (For example when CTRL is pressed). We will need an UI part
// for that first; and some important usability choices need to be made:
// E.g. which point should be used for pivoting? A previously snapped point,
// or a transformation center (which can be moved after clicking for the
// second time on an object; but should this point then be constrained to the
// line, or can it be located anywhere?)
_findCandidates(sp_document_root(_named_view->document), &it, true, NR::Rect(p, p), snap_dim, false, NR::identity());
_snapTranslatingGuideToNodes(sc, Inkscape::Snapper::SNAPPOINT_GUIDE, p, guide_normal);
// _snapRotatingGuideToNodes has not been implemented yet.
}
/**
* \return true if this Snapper will snap at least one kind of point.
*/
bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
{
bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
return (_snap_enabled && _snap_from != 0 && snap_to_something);
}
bool Inkscape::ObjectSnapper::GuidesMightSnap() const
{
bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
return (_snap_enabled && (_snap_from & SNAPPOINT_GUIDE) && snap_to_something);
}
void Inkscape::ObjectSnapper::_clear_paths() const
{
for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
g_free(*k);
}
_paths_to_snap_to->clear();
}
Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
{
Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_named_view->document),sp_document_height(_named_view->document)));
return _getPathvFromRect(border_rect);
}
Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
{
SPCurve const *border_curve = SPCurve::new_from_rect(rect);
if (border_curve) {
Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
return dummy;
} else {
return NULL;
}
}
void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<NR::Point> *points) const
{
Geom::Coord w = sp_document_width(_named_view->document);
Geom::Coord h = sp_document_height(_named_view->document);
points->push_back(Geom::Point(0,0));
points->push_back(Geom::Point(0,h));
points->push_back(Geom::Point(w,h));
points->push_back(Geom::Point(w,0));
}
/*
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 :