snap.cpp revision 5ee25de9ab2d1ebc0e9dfa81f6486b194b0fc731
#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) 1999-2010 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 "display/canvas-grid.h"
#include "display/snap-indicator.h"
#include "inkscape.h"
#include "desktop.h"
#include "selection.h"
#include "sp-guide.h"
#include "preferences.h"
#include "event-context.h"
/**
* Construct a SnapManager for a SPNamedView.
*
* \param v `Owning' SPNamedView.
*/
guide(this, 0),
object(this, 0),
snapprefs(),
_named_view(v)
{
}
/**
* \brief Return a list of snappers
*
* Inkscape snaps to objects, grids, and guides. For each of these snap targets a
* separate class is used, which has been derived from the base Snapper class. The
* getSnappers() method returns a list of pointers to instances of this class. This
* list contains exactly one instance of the guide snapper and of the object snapper
* class, but any number of grid snappers (because each grid has its own snapper
* instance)
*
* \return List of snappers that we use.
*/
SnapManager::getSnappers() const
{
return s;
}
/**
* \brief Return a list of gridsnappers
*
* Each grid has its own instance of the snapper class. This way snapping can
* be enabled per grid individually. A list will be returned containing the
* pointers to these instances, but only for grids that are being displayed
* and for which snapping is enabled.
*
* \return List of gridsnappers that we use.
*/
SnapManager::getGridSnappers() const
{
SnapperList s;
}
}
return s;
}
/**
* \brief Return true if any snapping might occur, whether its to grids, guides or objects
*
* Each snapper instance handles its own snapping target, e.g. grids, guides or
* objects. This method iterates through all these snapper instances and returns
* true if any of the snappers might possible snap, considering only the relevant
* snapping preferences.
*
* \return true if one of the snappers will try to snap to something.
*/
bool SnapManager::someSnapperMightSnap() const
{
return false;
}
SnapperList const s = getSnappers();
while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
i++;
}
return (i != s.end());
}
/**
* \return true if one of the grids might be snapped to.
*/
bool SnapManager::gridSnapperMightSnap() const
{
return false;
}
SnapperList const s = getGridSnappers();
while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
i++;
}
return (i != s.end());
}
/**
* \brief Try to snap a point to grids, guides or objects.
*
* Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
* i.e. snap in any direction on the two dimensional canvas to the nearest
* snap target. freeSnapReturnByRef() is equal in snapping behavior to
* freeSnap(), but the former returns the snapped point trough the referenced
* parameter p. This parameter p initially contains the position of the snap
* source and will we overwritten by the target position if snapping has occurred.
* This makes snapping transparent to the calling code. If this is not desired
* because either the calling code must know whether snapping has occurred, or
* because the original position should not be touched, then freeSnap() should be
* called instead.
*
* PS:
* 1) SnapManager::setup() must have been called before calling this method,
* but only once for a set of points
* 2) Only to be used when a single source point is to be snapped; it assumes
* that source_num = 0, which is inefficient when snapping sets our source points
*
* \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
* \param source_type Detailed description of the source type, will be used by the snap indicator
* \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
*/
{
Inkscape::SnappedPoint const s = freeSnap(Inkscape::SnapCandidatePoint(p, source_type), bbox_to_snap);
s.getPoint(p);
}
/**
* \brief Try to snap a point to grids, guides or objects.
*
* Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
* i.e. snap in any direction on the two dimensional canvas to the nearest
* snap target. freeSnap() is equal in snapping behavior to
* freeSnapReturnByRef(). Please read the comments of the latter for more details
*
* PS: SnapManager::setup() must have been called before calling this method,
* but only once for a set of points
*
* \param p Source point to be snapped
* \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
*/
{
if (!someSnapperMightSnap()) {
}
}
return findBestSnap(p, sc, false);
}
{
// setup() must have been called before calling this method!
if (_snapindicator) {
_snapindicator = false; // prevent other methods from drawing a snap indicator; we want to control this here
if (s.getSnapped()) {
} else {
}
_snapindicator = true; // restore the original value
}
}
/**
* \brief Snap to the closest multiple of a grid pitch
*
* 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 its pasted copy is a multiple of the grid pitch. If the source
* was aligned, then the copy will therefore also be aligned.
*
* PS: Whether we really find a multiple also depends on the snapping range! Most users
* will have "always snap" enabled though, in which case a multiple will always be found.
* PS2: When multiple grids are present then the result will become ambiguous. There is no
* way to control to which grid this method will snap.
*
* \param t Vector that represents the offset of the pasted copy with respect to the original
* \return Offset vector after snapping to the closest multiple of a grid pitch
*/
{
return t;
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
// Therefore 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::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH),Geom::OptRect(), NULL, NULL);
// Find the best snap for this grid, including intersections of the grid-lines
bool old_val = _snapindicator;
_snapindicator = false;
Inkscape::SnappedPoint s = findBestSnap(Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH), sc, false, false, true);
// use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
// doesn't tell us anything about which node to snap
success = true;
nearest_distance = s.getSnapDistance();
bestSnappedPoint = s;
}
}
}
if (success) {
return nearest_multiple;
}
}
return t;
}
/**
* \brief Try to snap a point along a constraint line to grids, guides or objects.
*
* Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
* i.e. snap in a specific direction on the two dimensional canvas to the nearest
* snap target.
*
* constrainedSnapReturnByRef() is equal in snapping behavior to
* constrainedSnap(), but the former returns the snapped point trough the referenced
* parameter p. This parameter p initially contains the position of the snap
* source and will we overwritten by the target position if snapping has occurred.
* This makes snapping transparent to the calling code. If this is not desired
* because either the calling code must know whether snapping has occurred, or
* because the original position should not be touched, then constrainedSnap() should
* be called instead.
*
* PS:
* 1) SnapManager::setup() must have been called before calling this method,
* but only once for a set of points
* 2) Only to be used when a single source point is to be snapped; it assumes
* that source_num = 0, which is inefficient when snapping sets our source points
*
* \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
* \param source_type Detailed description of the source type, will be used by the snap indicator
* \param constraint The direction or line along which snapping must occur
* \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
*/
{
Inkscape::SnappedPoint const s = constrainedSnap(Inkscape::SnapCandidatePoint(p, source_type, 0), constraint, bbox_to_snap);
s.getPoint(p);
}
/**
* \brief Try to snap a point along a constraint line to grids, guides or objects.
*
* Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
* i.e. snap in a specific direction on the two dimensional canvas to the nearest
* snap target. constrainedSnap is equal in snapping behavior to
* constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
*
* PS: SnapManager::setup() must have been called before calling this method,
* but only once for a set of points
*
* \param p Source point to be snapped
* \param constraint The direction or line along which snapping must occur
* \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
*/
{
// First project the mouse pointer onto the constraint
Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, NR_HUGE, 0, false, true, false);
if (!someSnapperMightSnap()) {
// Always return point on constraint
return no_snap;
}
}
if (result.getSnapped()) {
// only change the snap indicator if we really snapped to something
if (_snapindicator) {
}
return result;
}
return no_snap;
}
/**
* \brief Try to snap a point of a guide to another guide or to a node
*
* Try to snap a point of a guide to another guide or to a node in two degrees-
* of-freedom, i.e. snap in any direction on the two dimensional canvas to the
* nearest snap target. This method is used when dragging or rotating a guide
*
* PS: SnapManager::setup() must have been called before calling this method,
*
* \param p Current position of the point on the guide that is to be snapped; will be overwritten by the position of the snap target if snapping has occurred
* \param guide_normal Vector normal to the guide line
*/
void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
{
return;
}
return;
}
if (drag_type == SP_DRAG_ROTATE) {
}
// Snap to nodes
if (object.ThisSnapperMightSnap()) {
}
// Snap to guides & grid lines
}
s.getPoint(p);
}
/**
* \brief Try to snap a point on a guide to the intersection with another guide or a path
*
* Try to snap a point on a guide to the intersection of that guide with another
* guide or with a path. The snapped point will lie somewhere on the guide-line,
* making this is a constrained snap, i.e. in only one degree-of-freedom.
* This method is used when dragging the origin of the guide along the guide itself.
*
* PS: SnapManager::setup() must have been called before calling this method,
*
* \param p Current position of the point on the guide that is to be snapped; will be overwritten by the position of the snap target if snapping has occurred
* \param guide_normal Vector normal to the guide line
*/
{
return;
}
return;
}
Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN, Inkscape::SNAPTARGET_UNDEFINED);
// Snap to nodes or paths
Inkscape::Snapper::SnapConstraint cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
if (object.ThisSnapperMightSnap()) {
}
// Snap to guides & grid lines
}
s.getPoint(p);
}
/**
* \brief Method for snapping sets of points while they are being transformed
*
* Method for snapping sets of points while they are being transformed, when using
* for example the selector tool. This method is for internal use only, and should
* not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
* etc. instead.
*
* This is what is being done in this method: transform each point, find out whether
* a free snap or constrained snap is more appropriate, do the snapping, calculate
* some metrics to quantify the snap "distance", and see if it's better than the
* previous snap. Finally, the best ("nearest") snap from all these points is returned.
*
* \param points Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
* \param constraint The direction or line along which snapping must occur, 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 to which the transformation applies, if applicable.
* \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
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
*/
}
long source_num = 0;
for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
/* Work out the transformed version of this point */
Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
// add the current transformed point to the box hulling all transformed points
} else {
}
transformed_points.push_back(Inkscape::SnapCandidatePoint(transformed, (*i).getSourceType(), source_num));
source_num++;
}
/* The current best transformation */
/* The current best metric for the best transformation; lower is better, NR_HUGE
** means that we haven't snapped anything.
*/
// Warnings for the devs
g_warning("Non-uniform constrained scaling is not supported!");
}
// We do not yet allow for simultaneous rotation and scaling
g_warning("Unconstrained rotation is not supported!");
}
// std::cout << std::endl;
bool first_free_snap = true;
for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
/* Snap it */
Geom::Point const b = ((*i).getPoint() - origin); // vector to original point (not the transformed point! required for rotations!)
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 == ROTATE) {
// Geom::L2(b) is the radius of the circular constraint
} else if (transformation_type == TRANSLATE) {
// 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 specify the point through
// which the constraint-line runs here, for each point individually. (we could also have done this
// earlier on, e.g. in seltrans.cpp but we're being lazy there and don't want to add an iteration loop)
dedicated_constraint = Inkscape::Snapper::SnapConstraint((*i).getPoint(), constraint.getDirection());
} // else: leave the original constraint, e.g. for skewing
} else {
// When scaling, a point aligned either horizontally or vertically with the origin can only
// move in that specific direction; therefore it should only snap in that direction, otherwise
// we will get snapped points with an invalid transformation
} else {
// If we have a collection of SnapCandidatePoints, with mixed constrained snapping and free snapping
// requirements, then freeSnap might never see the SnapCandidatePoint with source_num == 0. The freeSnap()
// method in the object snapper depends on this, because only for source-num == 0 the target nodes will
// be collected. Therefore we enforce that the first SnapCandidatePoint that is to be freeSnapped always
// has source_num == 0;
// TODO: This is a bit ugly so fix this; do we need sourcenum for anything else? if we don't then get rid
// of it and explicitely communicate to the object snapper that this is a first point
if (first_free_snap) {
(*j).setSourceNum(0);
first_free_snap = false;
}
}
}
// std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
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 b = (*i - origin); // vector to original point
switch (transformation_type) {
case TRANSLATE:
/* 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!
*/
// Only for translations, the relevant metric will be the real snapped distance,
// so we don't have to do anything special here
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 of course)
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
}
}
if (uniform) {
} else {
}
}
// Compare the resulting scaling with the desired scaling
Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
break;
}
case STRETCH:
} else { // STRETCHING might occur for this point, but only when the stretching is uniform
}
}
// Store the metric for this transformation as a virtual distance
break;
case SKEW:
// Store the metric for this transformation as a virtual distance
break;
case ROTATE:
// a is vector to snapped point; b is vector to original point; now lets calculate angle between a and b
// Store the metric for this transformation as a virtual distance (we're storing an angle)
break;
default:
}
}
}
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;
}
/**
* \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
*
* \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
Inkscape::SnappedPoint SnapManager::freeSnapTranslate(std::vector<Inkscape::SnapCandidatePoint> const &p,
{
if (p.size() == 1) {
}
return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
}
/**
* \brief Apply a translation to a set of points and try to snap along a constraint
*
* \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param constraint The direction or line along which snapping must occur.
* \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapTranslate(std::vector<Inkscape::SnapCandidatePoint> const &p,
{
if (p.size() == 1) {
}
return _snapTransformed(p, pointer, true, constraint, TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
}
/**
* \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
*
* \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
* \param o Origin of the scaling
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
{
if (p.size() == 1) {
Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
}
return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
}
/**
* \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
*
* \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
* \param o Origin of the scaling
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
{
// When constrained scaling, only uniform scaling is supported.
if (p.size() == 1) {
Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
}
return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
}
/**
* \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
*
* \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
* \param o Origin of the stretching
* \param d Dimension in which to apply proposed stretch.
* \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
bool u) const
{
if (p.size() == 1) {
}
}
/**
* \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
*
* \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param constraint The direction or line along which snapping must occur.
* \param s Proposed skew; the final skew can only be calculated after snapping has occurred
* \param o Origin of the proposed skew
* \param d Dimension in which to apply proposed skew.
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
{
// "s" contains skew factor in s[0], and scale factor in s[1]
// Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
// the transformation of the bounding box is equal to the transformation of the individual nodes. This is
// NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
// so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
// of bounding boxes is not allowed here.
if (p.size() > 0) {
}
if (p.size() == 1) {
}
}
/**
* \brief Apply a rotation to a set of points and snap, without scaling
*
* \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
* \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
* \param angle Proposed rotation (in radians); the final rotation can only be calculated after snapping has occurred
* \param o Origin of the rotation
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
*/
Inkscape::SnappedPoint SnapManager::constrainedSnapRotate(std::vector<Inkscape::SnapCandidatePoint> const &p,
{
// Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
// the transformation of the bounding box is equal to the transformation of the individual nodes. This is
// NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
// so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
// of bounding boxes is not allowed here.
if (p.size() == 1) {
}
return _snapTransformed(p, pointer, true, Geom::Point(0,0), ROTATE, Geom::Point(angle, angle), o, Geom::X, false);
}
/**
* \brief Given a set of possible snap targets, find the best target (which is not necessarily
* also the nearest target), and show the snap indicator if requested
*
* \param p Source point to be snapped
* \param sc A structure holding all snap targets that have been found so far
* \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
* \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
* \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid)
* \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
*/
SnappedConstraints const &sc,
bool constrained,
bool noCurves,
bool allowOffScreen) 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;
std::cout << " Curves : " << sc.curves.size()<< std::endl;
*/
// Store all snappoints
// search for the closest snapped point
}
// search for the closest snapped curve
if (!noCurves) {
}
}
if (snapprefs.getSnapIntersectionCS()) {
// search for the closest snapped intersection of curves
if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
}
}
// 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 (snapprefs.getSnapIntersectionGG()) {
}
}
}
// now let's see which snapped point gets a thumbs up
// std::cout << "Finding the best snap..." << std::endl;
for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
// std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
// if it's the first point, or if it is closer than the best snapped point so far
// then prefer this point over the previous one
bestSnappedPoint = *i;
}
}
}
// std::cout << std::endl;
}
// Update the snap indicator, if requested
if (_snapindicator) {
if (bestSnappedPoint.getSnapped()) {
} else {
}
}
// std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
return bestSnappedPoint;
}
/// Convenience shortcut when there is only one item to ignore
bool snapindicator,
SPItem const *item_to_ignore,
{
}
/**
* \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
* to ignore and toggling the snap indicator
*
* There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
* whereas this one will take a list of items to ignore
*
* \param desktop Reference to the desktop to which this snap manager is attached
* \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
* \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
* \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
* that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
* unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
* \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
*/
bool snapindicator,
{
}
/// Setup, taking the list of items to ignore from the desktop's selection.
bool snapindicator,
{
}
}
{
return _named_view->document;
}
/**
* \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
*
* \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
* \param transformation_type Type of transformation to apply.
* \param transformation Mathematical description of the transformation; details depend on the type.
* \param origin Origin of the transformation, if applicable.
* \param dim Dimension to which the transformation applies, if applicable.
* \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
* \return The position of the point after transformation
*/
bool const uniform) const
{
/* Work out the transformed version of this point */
switch (transformation_type) {
case TRANSLATE:
break;
case SCALE:
transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
break;
case STRETCH:
{
if (uniform)
else {
}
break;
}
case SKEW:
// Apply the skew factor
transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[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
break;
case ROTATE:
// for rotations: transformation[0] stores the angle in radians
break;
default:
}
return transformed;
}
/**
* \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
*
* \param point_type Category of points to which the source point belongs: node, guide or bounding box
* \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
*/
if (snapprefs.getSnapEnabledGlobally() && (p_is_other || (p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
} else {
}
}
}
/*
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 :