object-snapper.cpp revision f200d31b8a03050faa7243929bbd5698db488399
/**
* \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 "document.h"
#include "sp-namedview.h"
#include "sp-image.h"
#include "sp-item-group.h"
#include "sp-item.h"
#include "sp-use.h"
#include "inkscape.h"
#include "preferences.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"
#include "desktop.h"
{
}
{
_candidates->clear();
delete _candidates;
delete _points_to_snap_to;
_clear_paths();
delete _paths_to_snap_to;
}
/**
* \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
*/
{
}
{
return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
}
/**
* 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 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.
*/
bool const &first_point,
DimensionToSnap const snap_dim,
bool const clip_or_mask,
{
return;
}
if (first_point) {
_candidates->clear();
}
// Snapping to items in a locked layer is allowed
// Don't snap to hidden objects, unless they're a clipped path or a mask
/* See if this item is on the ignore list */
i++;
}
}
if (item) {
if (!clip_or_mask) { // 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
if (obj) {
}
if (obj) {
}
}
}
if (SP_IS_GROUP(o)) {
} 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)
true);
} else {
}
if (bbox_of_item) {
// See if the item is within range
// This item is within snapping range, so record it as a candidate
// For debugging: print the id of the candidate to the console
//SPObject *obj = (SPObject*)item;
//std::cout << "Snap candidate added: " << obj->id << std::endl;
}
}
}
}
}
}
}
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) {
// Determine the type of bounding box we should snap to
// 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_other) || (p_is_a_node && p_is_other)));
if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
bbox_type = !prefs_bbox ?
}
// Consider the page border for snapping to
}
for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
//Geom::Matrix i2doc(Geom::identity());
}
//Collect all nodes so we can snap to them
// Note: there are two ways in which intersections are considered:
// Method 1: Intersections are calculated for each shape individually, for both the
// snap source and snap target (see sp_shape_snappoints)
// Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
// the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
// Some differences:
// - Method 1 doesn't find intersections within a set of multiple objects
// - Method 2 only works for targets
// When considering intersections as snap targets:
// - Method 1 only works when snapping to nodes, whereas
// - Method 2 only works when snapping to paths
// - There will be performance differences too!
// If both methods are being used simultaneously, then this might lead to duplicate targets!
// Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
// When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
// go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
// temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
// paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
}
}
}
//Collect the bounding box's corners so we can snap to them
// 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) {
getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
}
}
}
}
}
Inkscape::SnapCandidatePoint const &p,
{
// Iterate through all nodes, find out which one is the closest to p, and snap to it!
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<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
s = SnappedPoint((*k).getPoint(), p.getSourceType(), p.getSourceNum(), (*k).getTargetType(), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, (*k).getTargetBBox());
success = true;
}
}
if (success) {
}
}
{
// Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
_collectNodes(SNAPSOURCE_GUIDE, true);
// Although we won't snap to paths here (which would give us under constrained snaps) we can still snap to intersections of paths.
if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
// The paths themselves should be discarded in findBestSnap(), as we should only snap to their intersections
}
SnappedPoint s;
for (std::vector<SnapCandidatePoint>::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)
Geom::Point p_proj = Geom::projection((*k).getPoint(), Geom::Line(p, p + Geom::rot90(guide_normal)));
Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
s = SnappedPoint((*k).getPoint(), SNAPSOURCE_GUIDE, 0, (*k).getTargetType(), dist, tol, getSnapperAlwaysSnap(), true, (*k).getTargetBBox());
}
}
}
/**
* Returns index of first NR_END bpath in array.
*/
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
bbox_type = !prefs_bbox ?
}
// Consider the page border for snapping
if (border_path != NULL) {
_paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(border_path, SNAPTARGET_PAGE_BORDER, Geom::OptRect()));
}
}
for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
/* Transform the requested snap point to this item's coordinates */
/* We might have a clone at hand, so make sure we get the root item */
} else {
}
//Build a list of all paths considered for snapping to
//Add the item's path to snap to
// 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;
}
// 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)) {
}
if (!very_lenghty_prose && !very_complex_path) {
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(Inkscape::SnapCandidatePath(borderpathv, SNAPTARGET_PATH, Geom::OptRect())); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
}
}
}
}
//Add the item's bounding box to snap to
// 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) {
if (rect) {
}
}
}
}
}
}
}
Inkscape::SnapCandidatePoint const &p,
SPPath const *selected_path) const
{
_collectPaths(p, p.getSourceNum() == 0);
// Now we can finally do the real snapping, using the paths collected above
if (p.getSourceNum() == 0) {
/* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
* currently being edited, because that path requires special care: when snapping to nodes
* only the unselected nodes of that path should be considered, and these will be passed on separately.
* This path must not be ignored however when snapping to the paths, so we add it here
* manually when applicable.
* */
if (node_tool_active) {
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(Inkscape::SnapCandidatePath(pathv, SNAPTARGET_PATH, Geom::OptRect(), true));
}
}
}
for (std::vector<Inkscape::SnapCandidatePath >::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
//if true then this pathvector it_pv is currently being edited in the node tool
for(Geom::PathVector::iterator it_pv = (it_p->path_vector)->begin(); it_pv != (it_p->path_vector)->end(); ++it_pv) {
// Find a nearest point for each curve within this path
// n curves will return n time values with 0 <= t <= 1
unsigned int index = 0;
bool c1 = true;
bool c2 = true;
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
*/
/* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
* snap to path segments that are not stationary. There are at least two possible ways to overcome this:
* - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
* used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
* should be in the exact same order for both classes, so we can index them
* - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
*/
}
if (dist < getSnapperTolerance()) {
sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, p.getSourceType(), p.getSourceNum(), it_p->target_type, it_p->target_bbox));
}
}
}
} // End of: for (Geom::PathVector::iterator ....)
}
}
/* Returns true if point is coincident with one of the unselected nodes */
bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Inkscape::SnapCandidatePoint> const *unselected_nodes) const
{
if (unselected_nodes == NULL) {
return false;
}
if (unselected_nodes->size() == 0) {
return false;
}
for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
return true;
}
}
return false;
}
Inkscape::SnapCandidatePoint const &p,
ConstraintLine const &c) const
{
_collectPaths(p, p.getSourceNum() == 0);
// Now we can finally do the real snapping, using the paths collected above
if (!is_zero(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
Geom::Point const p_proj_on_cl = p.getPoint(); // projection has already been taken care of in constrainedSnap in the snapmanager;
Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
if (k->path_vector) {
// 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->first
// Reconstruct the point of intersection
// 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)
SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), p.getSourceType(), p.getSourceNum(), k->target_type, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, k->target_bbox);
}
}
}
}
}
}
Inkscape::SnapCandidatePoint const &p,
{
return;
}
/* Get a list of all the SPItems that we will try to snap to */
if (p.getSourceNum() == 0) {
Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
_findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
}
|| _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
|| _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
}
if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
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
*/
} // else: *it->begin() might be a SPGroup, e.g. when editing a LPE of text that has been converted to a group of paths
// as reported in bug #356743. In that case we can just ignore it, i.e. not snap to this item
}
} else {
}
}
}
Inkscape::SnapCandidatePoint const &p,
ConstraintLine const &c,
{
return;
}
/* Get a list of all the SPItems that we will try to snap to */
if (p.getSourceNum() == 0) {
Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
_findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
}
// A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
// This is useful 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 (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
_snapPathsConstrained(sc, p, c);
}
}
// This method is used to snap a guide to nodes, while dragging the guide around
{
/* Get a list of all the SPItems that we will try to snap to */
} else {
}
_findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
}
// This method is used to snap the origin of a guide to nodes/paths, while dragging the origin along the guide
ConstraintLine const &/*c*/) const
{
/* Get a list of all the SPItems that we will try to snap to */
} else {
}
_findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
}
/**
* \return true if this Snapper will snap at least one kind of point.
*/
{
|| _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
|| _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
}
bool Inkscape::ObjectSnapper::GuidesMightSnap() const // almost the same as ThisSnapperMightSnap above, but only looking at points (and not paths)
{
|| (_snapmanager->snapprefs.getSnapModeBBox() && (_snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()))
|| (_snapmanager->snapprefs.getSnapModeNode() && (_snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()))
|| (_snapmanager->snapprefs.getSnapModeNode() && (_snapmanager->snapprefs.getSnapToItemPath() && _snapmanager->snapprefs.getSnapIntersectionCS()));
}
{
for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
g_free(k->path_vector);
}
}
{
Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
return _getPathvFromRect(border_rect);
}
{
if (border_curve) {
return dummy;
} else {
return NULL;
}
}
{
points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
}
bool const /*isTarget*/,
bool const includeCorners,
bool const includeLineMidpoints,
bool const includeObjectMidpoints)
{
if (bbox) {
// collect the corners of the bounding box
for ( unsigned k = 0 ; k < 4 ; k++ ) {
if (includeCorners) {
points->push_back(Inkscape::SnapCandidatePoint(bbox->corner(k), Inkscape::SNAPSOURCE_BBOX_CORNER, 0, Inkscape::SNAPTARGET_BBOX_CORNER, *bbox));
}
// optionally, collect the midpoints of the bounding box's edges too
if (includeLineMidpoints) {
points->push_back(Inkscape::SnapCandidatePoint((bbox->corner(k) + bbox->corner((k+1) % 4))/2, Inkscape::SNAPSOURCE_BBOX_EDGE_MIDPOINT, 0, Inkscape::SNAPTARGET_BBOX_EDGE_MIDPOINT, *bbox));
}
}
if (includeObjectMidpoints) {
points->push_back(Inkscape::SnapCandidatePoint(bbox->midpoint(), Inkscape::SNAPSOURCE_BBOX_MIDPOINT, 0, Inkscape::SNAPTARGET_BBOX_MIDPOINT, *bbox));
}
}
}
/*
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 :