1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
// SPDX-License-Identifier: GPL-2.0-or-later
#ifndef SEEN_SNAPPER_H
#define SEEN_SNAPPER_H
/**
* \file src/snapper.h
* \brief Snapper class.
*
* Authors:
* Carl Hetherington <inkscape@carlh.net>
* Diederik van Lierop <mail@diedenrezi.nl>
*
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#include <optional>
#include <cstdio>
#include <list>
#include "snap-candidate.h"
#include "snapped-point.h"
#include "snapped-line.h"
#include "snapped-curve.h"
struct IntermSnapResults {
std::list<Inkscape::SnappedPoint> points;
std::list<Inkscape::SnappedLine> grid_lines;
std::list<Inkscape::SnappedLine> guide_lines;
std::list<Inkscape::SnappedCurve> curves;
};
class SnapManager;
class SPObject;
namespace Inkscape
{
/// Parent for classes that can snap points to something
class Snapper
{
public:
//Snapper() {} //does not seem to be used somewhere
Snapper(SnapManager *sm, ::Geom::Coord const t);
virtual ~Snapper() = default;
virtual Geom::Coord getSnapperTolerance() const = 0; //returns the tolerance of the snapper in screen pixels (i.e. independent of zoom)
virtual bool getSnapperAlwaysSnap() const = 0; //if true, then the snapper will always snap, regardless of its tolerance
/**
* \return true if this Snapper will snap at least one kind of point.
*/
virtual bool ThisSnapperMightSnap() const {return _snap_enabled;} // will likely be overridden by derived classes
// These four methods are only used for grids, for which snapping can be enabled individually
void setEnabled(bool s);
void setSnapVisibleOnly(bool s);
bool getEnabled() const {return _snap_enabled;}
bool getSnapVisibleOnly() const {return _snap_visible_only;}
virtual void freeSnap(IntermSnapResults &/*isr*/,
Inkscape::SnapCandidatePoint const &/*p*/,
Geom::OptRect const &/*bbox_to_snap*/,
std::vector<SPObject const *> const */*it*/,
std::vector<SnapCandidatePoint> */*unselected_nodes*/) const {};
// Class for storing the constraint for constrained snapping; can be
// - a line (infinite line with origin, running through _point pointing in _direction)
// - a direction (infinite line without origin, i.e. only a direction vector, stored in _direction)
// - a circle (_point denotes the center, _radius doesn't need an explanation, _direction contains
// the vector from the origin to the original untransformed point);
class SnapConstraint
{
private:
enum SnapConstraintType {LINE, DIRECTION, CIRCLE, UNDEFINED};
public:
// Constructs a direction constraint, e.g. horizontal or vertical but without a specified point
SnapConstraint(Geom::Point const &d) : _point(), _direction(d), _radius(0), _type(DIRECTION) {}
// Constructs a linear constraint
SnapConstraint(Geom::Point const &p, Geom::Point const &d) : _point(p), _direction(d), _radius(0), _type(LINE) {}
// Orthogonal version
SnapConstraint(Geom::Point const &p, Geom::Dim2 const &d) : _point(p), _direction(), _radius(0), _type(LINE) {_direction[d] = 1.;}
SnapConstraint(Geom::Line const &l) : _point(l.origin()), _direction(l.versor()), _radius(0), _type(LINE) {}
// Constructs a circular constraint
SnapConstraint(Geom::Point const &p, Geom::Point const &d, Geom::Coord const &r) : _point(p), _direction(d), _radius(r), _type(CIRCLE) {}
// Undefined, or empty constraint
SnapConstraint() : _point(), _direction(), _radius(0), _type(UNDEFINED) {}
bool hasPoint() const {return _type != DIRECTION && _type != UNDEFINED;}
Geom::Point getPoint() const {
assert(_type != DIRECTION && _type != UNDEFINED);
return _point;
}
Geom::Point getDirection() const {
return _direction;
}
Geom::Coord getRadius() const {
assert(_type == CIRCLE);
return _radius;
}
bool isCircular() const { return _type == CIRCLE; }
bool isLinear() const { return _type == LINE; }
bool isDirection() const { return _type == DIRECTION; }
bool isUndefined() const { return _type == UNDEFINED; }
Geom::Point projection(Geom::Point const &p) const { // returns the projection of p on this constraint
if (_type == CIRCLE) {
// project on to a circular constraint
Geom::Point v_orig = p - _point;
Geom::Coord l = Geom::L2(v_orig);
if (l > 0) {
return _point + _radius * v_orig/l; // Length of _direction is equal to the radius
} else {
// point to be projected is exactly at the center of the circle, so any point on the circle is a projection
return _point + Geom::Point(_radius, 0);
}
} else if (_type != UNDEFINED){
// project on to a linear constraint
Geom::Point const p1_on_cl = (_type == LINE) ? _point : p;
Geom::Point const p2_on_cl = p1_on_cl + _direction;
return Geom::projection(p, Geom::Line(p1_on_cl, p2_on_cl));
} else {
printf("WARNING: Bug: trying to find the projection onto an undefined constraint");
return Geom::Point();
}
}
private:
Geom::Point _point;
Geom::Point _direction;
Geom::Coord _radius;
SnapConstraintType _type;
};
virtual void constrainedSnap(IntermSnapResults &/*isr*/,
Inkscape::SnapCandidatePoint const &/*p*/,
Geom::OptRect const &/*bbox_to_snap*/,
SnapConstraint const &/*c*/,
std::vector<SPObject const *> const */*it*/,
std::vector<SnapCandidatePoint> */*unselected_nodes*/) const {};
protected:
SnapManager *_snapmanager;
// This is only used for grids, for which snapping can be enabled individually
bool _snap_enabled; ///< true if this snapper is enabled, otherwise false
bool _snap_visible_only;
};
}
#endif /* !SEEN_SNAPPER_H */
/*
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 :
|
