1 #ifndef LIBNR_NR_RECT_H_SEEN
2 #define LIBNR_NR_RECT_H_SEEN
4 /** \file
5 * Definitions of NRRect and NR::Rect types, and some associated functions \& macros.
6 */
7 /*
8 * Authors:
9 * Lauris Kaplinski <lauris@kaplinski.com>
10 * Nathan Hurst <njh@mail.csse.monash.edu.au>
11 * MenTaLguY <mental@rydia.net>
12 *
13 * This code is in public domain
14 */
17 #include <stdexcept>
18 #include <limits>
20 #include "libnr/nr-values.h"
21 #include <libnr/nr-coord.h>
22 #include <libnr/nr-i-coord.h>
23 #include <libnr/nr-dim2.h>
24 #include <libnr/nr-point.h>
25 #include <libnr/nr-maybe.h>
26 #include <libnr/nr-point-matrix-ops.h>
28 namespace NR {
29 struct Matrix;
31 /** A rectangle is always aligned to the X and Y axis. This means it
32 * can be defined using only 4 coordinates, and determining
33 * intersection is very efficient. The points inside a rectangle are
34 * min[dim] <= _pt[dim] <= max[dim]. A rectangle may be empty, in the
35 * sense of having zero area, but it will always contain at least one
36 * point. Infinities are also permitted.
37 */
38 class Rect {
39 public:
40 Rect() : _min(-_inf(), -_inf()), _max(_inf(), _inf()) {}
41 Rect(Point const &p0, Point const &p1);
43 Point const &min() const { return _min; }
44 Point const &max() const { return _max; }
46 /** returns the four corners of the rectangle in order
47 * (clockwise if +Y is up, anticlockwise if +Y is down) */
48 Point corner(unsigned i) const;
50 /** returns a vector from min to max. */
51 Point dimensions() const;
53 /** returns the midpoint of this rect. */
54 Point midpoint() const;
56 /** True iff either width or height is less than \a epsilon. */
57 bool isEmpty(double epsilon=1e-6) const {
58 return isEmpty<X>(epsilon) || isEmpty<Y>(epsilon);
59 }
61 bool intersects(Rect const &r) const {
62 return intersects<X>(r) && intersects<Y>(r);
63 }
64 bool contains(Rect const &r) const {
65 return contains<X>(r) && contains<Y>(r);
66 }
67 bool contains(Point const &p) const {
68 return contains<X>(p) && contains<Y>(p);
69 }
71 double area() const {
72 return extent<X>() * extent<Y>();
73 }
75 double maxExtent() const {
76 return MAX(extent<X>(), extent<Y>());
77 }
79 double extent(Dim2 const axis) const {
80 switch (axis) {
81 case X: return extent<X>();
82 case Y: return extent<Y>();
83 default: g_error("invalid axis value %d", (int) axis); return 0;
84 };
85 }
87 double extent(unsigned i) const throw(std::out_of_range) {
88 switch (i) {
89 case 0: return extent<X>();
90 case 1: return extent<Y>();
91 default: throw std::out_of_range("Dimension out of range");
92 };
93 }
95 /**
96 \brief Remove some precision from the Rect
97 \param places The number of decimal places left in the end
99 This function just calls round on the \c _min and \c _max points.
100 */
101 inline void round(int places = 0) {
102 _min.round(places);
103 _max.round(places);
104 return;
105 }
107 /** Translates the rectangle by p. */
108 void offset(Point p);
110 /** Makes this rectangle large enough to include the point p. */
111 void expandTo(Point p);
113 /** Makes this rectangle large enough to include the rectangle r. */
114 void expandTo(Rect const &r);
116 inline void move_left (gdouble by) {
117 _min[NR::X] += by;
118 }
119 inline void move_right (gdouble by) {
120 _max[NR::X] += by;
121 }
122 inline void move_top (gdouble by) {
123 _min[NR::Y] += by;
124 }
125 inline void move_bottom (gdouble by) {
126 _max[NR::Y] += by;
127 }
129 void growBy (gdouble by);
131 /** Scales the rect by s, with origin at 0, 0 */
132 inline Rect operator*(double const s) const {
133 return Rect(s * min(), s * max());
134 }
136 /** Transforms the rect by m. Note that it gives correct results only for scales and translates */
137 inline Rect operator*(Matrix const m) const {
138 return Rect(_min * m, _max * m);
139 }
141 inline bool operator==(Rect const &in_rect) {
142 return ((this->min() == in_rect.min()) && (this->max() == in_rect.max()));
143 }
145 friend inline std::ostream &operator<<(std::ostream &out_file, NR::Rect const &in_rect);
147 private:
148 Rect(Nothing) : _min(1, 1), _max(-1, -1) {}
150 static double _inf() {
151 return std::numeric_limits<double>::infinity();
152 }
154 template <NR::Dim2 axis>
155 double extent() const {
156 return _max[axis] - _min[axis];
157 }
159 template <NR::Dim2 axis>
160 bool isEmpty(double epsilon) const {
161 return extent<axis>() < epsilon;
162 }
164 template <Dim2 axis>
165 bool intersects(Rect const &r) const {
166 return _max[axis] >= r._min[axis] && _min[axis] <= r._max[axis];
167 }
169 template <Dim2 axis>
170 bool contains(Rect const &r) const {
171 return contains(r._min) && contains(r._max);
172 }
174 template <Dim2 axis>
175 bool contains(Point const &p) const {
176 return p[axis] >= _min[axis] && p[axis] <= _max[axis];
177 }
179 Point _min, _max;
181 friend class MaybeStorage<Rect>;
182 friend Maybe<Rect> intersection(Maybe<Rect> const &, Maybe<Rect> const &);
183 friend Rect union_bounds(Rect const &, Rect const &);
184 };
186 template <>
187 class MaybeStorage<Rect> {
188 public:
189 MaybeStorage() : _rect(Nothing()) {}
190 MaybeStorage(Rect const &rect) : _rect(rect) {}
192 bool is_nothing() const {
193 return _rect._min[X] > _rect._max[X];
194 }
195 Rect const &value() const { return _rect; }
196 Rect &value() { return _rect; }
198 private:
199 Rect _rect;
200 };
202 /** Returns the set of points shared by both rectangles. */
203 Maybe<Rect> intersection(Maybe<Rect> const & a, Maybe<Rect> const & b);
205 /** Returns the smallest rectangle that encloses both rectangles. */
206 Rect union_bounds(Rect const &a, Rect const &b);
207 inline Rect union_bounds(Maybe<Rect> const & a, Rect const &b) {
208 if (a) {
209 return union_bounds(*a, b);
210 } else {
211 return b;
212 }
213 }
214 inline Rect union_bounds(Rect const &a, Maybe<Rect> const & b) {
215 if (b) {
216 return union_bounds(a, *b);
217 } else {
218 return a;
219 }
220 }
221 inline Maybe<Rect> union_bounds(Maybe<Rect> const & a, Maybe<Rect> const & b)
222 {
223 if (!a) {
224 return b;
225 } else if (!b) {
226 return a;
227 } else {
228 return union_bounds(*a, *b);
229 }
230 }
232 /** A function to print out the rectange if sent to an output
233 stream. */
234 inline std::ostream
235 &operator<<(std::ostream &out_file, NR::Rect const &in_rect)
236 {
237 out_file << "Rectangle:\n";
238 out_file << "\tMin Point -> " << in_rect.min() << "\n";
239 out_file << "\tMax Point -> " << in_rect.max() << "\n";
241 return out_file;
242 }
244 } /* namespace NR */
246 /* legacy rect stuff */
248 struct NRMatrix;
250 /* NULL rect is infinite */
252 struct NRRect {
253 NRRect() {}
254 NRRect(NR::Coord xmin, NR::Coord ymin, NR::Coord xmax, NR::Coord ymax)
255 : x0(xmin), y0(ymin), x1(xmin), y1(ymin)
256 {}
257 explicit NRRect(NR::Rect const &rect);
258 explicit NRRect(NR::Maybe<NR::Rect> const &rect);
259 operator NR::Maybe<NR::Rect>() const { return upgrade(); }
260 NR::Maybe<NR::Rect> upgrade() const;
262 NR::Coord x0, y0, x1, y1;
263 };
265 #define nr_rect_d_set_empty(r) (*(r) = NR_RECT_EMPTY)
266 #define nr_rect_l_set_empty(r) (*(r) = NR_RECT_L_EMPTY)
268 /** "Empty" here includes the case of zero width or zero height. */
269 #define nr_rect_d_test_empty(r) ((r) && NR_RECT_DFLS_TEST_EMPTY(r))
270 #define nr_rect_l_test_empty(r) ((r) && NR_RECT_DFLS_TEST_EMPTY(r))
272 #define nr_rect_d_test_intersect(r0,r1) \
273 (!nr_rect_d_test_empty(r0) && !nr_rect_d_test_empty(r1) && \
274 !((r0) && (r1) && !NR_RECT_DFLS_TEST_INTERSECT(r0, r1)))
275 #define nr_rect_l_test_intersect(r0,r1) \
276 (!nr_rect_l_test_empty(r0) && !nr_rect_l_test_empty(r1) && \
277 !((r0) && (r1) && !NR_RECT_DFLS_TEST_INTERSECT(r0, r1)))
279 #define nr_rect_d_point_d_test_inside(r,p) ((p) && (!(r) || (!NR_RECT_DF_TEST_EMPTY(r) && NR_RECT_DF_POINT_DF_TEST_INSIDE(r,p))))
280 #define nr_rect_l_point_l_test_inside(r,p) ((p) && (!(r) || (!NR_RECT_DFLS_TEST_EMPTY(r) && NR_RECT_LS_POINT_LS_TEST_INSIDE(r,p))))
281 #define nr_rect_l_test_inside(r,x,y) ((!(r) || (!NR_RECT_DFLS_TEST_EMPTY(r) && NR_RECT_LS_TEST_INSIDE(r,x,y))))
283 // returns minimal rect which covers all of r0 not covered by r1
284 NRRectL *nr_rect_l_subtract(NRRectL *d, NRRectL const *r0, NRRectL const *r1);
286 // returns the area of r
287 NR::ICoord nr_rect_l_area(NRRectL *r);
289 /* NULL values are OK for r0 and r1, but not for d */
290 NRRect *nr_rect_d_intersect(NRRect *d, NRRect const *r0, NRRect const *r1);
291 NRRectL *nr_rect_l_intersect(NRRectL *d, NRRectL const *r0, NRRectL const *r1);
293 NRRect *nr_rect_d_union(NRRect *d, NRRect const *r0, NRRect const *r1);
294 NRRectL *nr_rect_l_union(NRRectL *d, NRRectL const *r0, NRRectL const *r1);
296 NRRect *nr_rect_union_pt(NRRect *dst, NR::Point const &p);
297 NRRect *nr_rect_d_union_xy(NRRect *d, NR::Coord x, NR::Coord y);
298 NRRectL *nr_rect_l_union_xy(NRRectL *d, NR::ICoord x, NR::ICoord y);
300 NRRect *nr_rect_d_matrix_transform(NRRect *d, NRRect const *s, NR::Matrix const &m);
301 NRRect *nr_rect_d_matrix_transform(NRRect *d, NRRect const *s, NRMatrix const *m);
302 NRRectL *nr_rect_l_enlarge(NRRectL *d, int amount);
305 #endif /* !LIBNR_NR_RECT_H_SEEN */
307 /*
308 Local Variables:
309 mode:c++
310 c-file-style:"stroustrup"
311 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
312 indent-tabs-mode:nil
313 fill-column:99
314 End:
315 */
316 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :