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"
/**
* Construct a SnapManager for a SPNamedView.
*
* \param v `Owning' SPNamedView.
*/
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::getSnappers() const
{
return s;
}
/**
* \return List of gridsnappers that we use.
*/
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
}
}
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();
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
* paths, grids or guides). To select either of these modes (or both), use the
* methods defined below: setSnapModeBBox() and setSnapModeNode().
*
* */
{
//The default values are being set in sp_namedview_set() (in sp-namedview.cpp)
}
//object.setSnapToBBoxNode(enabled); // On second thought, these should be controlled
//object.setSnapToBBoxPath(enabled); // separately by the snapping prefs dialog
}
bool SnapManager::getSnapModeBBox() const
{
}
{
}
//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
{
}
{
}
bool SnapManager::getSnapModeGuide() const
{
}
/**
* 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.
*/
bool first_point,
{
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.
*/
bool first_point,
{
if (!SomeSnapperMightSnap()) {
}
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
} else {
}
}
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!
{
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
bool success = false;
// 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
// 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
// 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
success = true;
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.
*/
bool first_point,
{
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.
*/
bool first_point,
{
if (!SomeSnapperMightSnap()) {
}
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
} else {
}
}
if (_item_to_ignore) {
delete items_to_ignore;
}
return findBestSnap(p, sc, true);
}
{
// This method is used to snap a guide to nodes, while dragging the guide around
return;
}
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.
*/
bool constrained,
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) {
return Inkscape::SnappedPoint();
}
/* Work out the transformed version of this point */
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:
{
if (uniform)
else {
}
break;
}
case SKEW:
// Apply the skew factor
// While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
// Apply that scale factor here
break;
default:
}
// add the current transformed point to the box hulling all transformed points
} else {
}
}
/* The current best transformation */
/* The current best metric for the best transformation; lower is better, NR_HUGE
** means that we haven't snapped anything.
*/
// std::cout << std::endl;
/* Snap it */
if (constrained) {
// 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
} 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.
} // else: leave the original constraint, e.g. for skewing
g_warning("Non-uniform constrained scaling is not supported!");
}
} else {
}
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.
*/
switch (transformation_type) {
case TRANSLATION:
/* 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!
*/
break;
case SCALE:
{
// 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)
if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
}
// 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
break;
}
case STRETCH:
} else { // STRETCHING might occur for this point, but only when the stretching is uniform
}
}
break;
case SKEW:
result[0] = (snapped_point.getPoint()[dim] - (*i)[dim]) / ((*i)[1 - dim] - origin[1 - dim]); // skew factor
break;
default:
}
/* Note it if it's the best so far */
if (transformation_type == SCALE) {
// 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)
// std::cout << "SEL ";
} // else { std::cout << " ";}
}
if (uniform) {
} else {
}
}
// std::cout << "P_orig = " << (*i) << " | scale_metric = " << scale_metric << " | distance = " << snapped_point.getDistance() << " | P_snap = " << snapped_point.getPoint() << std::endl;
} else {
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 c4 = snapped_point.getAlwaysSnap() == true && best_snapped_point.getAlwaysSnap() == false;
bool const c4n = snapped_point.getAlwaysSnap() == false && best_snapped_point.getAlwaysSnap() == true;
// 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
} else {
}
}
}
}
// Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
// These rounding errors might be caused by NRRects, see bug #1584301
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.
*/
{
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,
{
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.
*/
{
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.
*/
{
// 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.
*/
bool u) const
{
}
/**
* 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.
*/
{
// "s" contains skew factor in s[0], and scale factor in s[1]
}
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
// search for the closest snapped point
}
// search for the closest snapped curve
}
if (_intersectionCS) {
// search for the closest snapped intersection of curves
}
}
// search for the closest snapped grid line
}
// search for the closest snapped guide line
}
// 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
// no need to look for additional intersections
if (!constrained) {
// search for the closest snapped intersection of grid lines
}
// search for the closest snapped intersection of guide lines
}
// search for the closest snapped intersection of grid with guide lines
if (_intersectionGG) {
}
}
}
// 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
// or, if it's closer
// or, if it's for a snapper with "always snap" turned on, and the previous wasn't
// But in no case fall back from a snapper with "always snap" on to one with "always snap" off
// or, if it's just as close then consider the second distance
// (which is only relevant for points at an intersection)
// then prefer this point over the previous one
bestSnappedPoint = *i;
}
}
}
// Update the snap indicator, if requested
if (_snapindicator) {
if (bestSnappedPoint.getSnapped()) {
} else {
}
}
// 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)
{
}
void SnapManager::setup(SPDesktop const *desktop, bool snapindicator, std::vector<SPItem const *> &items_to_ignore, std::vector<Geom::Point> *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 :