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KJB
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KJB
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represents an open polygonal path with a tangent at each point More...
#include <polypath.h>
Public Member Functions | |
| const PixPath & | get_vertices () const |
| provide read-only access to the sequence of polygon vertices More... | |
| Vector2 | tangent_at (const_iterator i) const |
| access unit vector at a point along path, spec by const_iterator More... | |
| Vector2 | tangent_at (size_t ix) const |
| access unit vector at a point along path, specified by index More... | |
| bool | is_a_vertex (size_t ix) const |
| test whether the point at a given index is a polygonal vertex More... | |
| int | debug_print (std::ostream &) const |
| print the inner state of a PolyPath object to a stream More... | |
 Public Member Functions inherited from kjb::qd::PixPath | |
| virtual | ~PixPath () |
| obligatory dtor More... | |
| virtual PixPath & | assign (unsigned index, const PixPoint &newp) |
| Change a member of the path to a new PixPoint. More... | |
| const PixPoint & | operator[] (unsigned index) const |
| Vector-like access to points (returning an rvalue). More... | |
| virtual void | push_back (const PixPoint &pp) |
| Vector-like appending a new PixPoint on the end of the object. More... | |
| virtual void | pop_back () |
| size_t | size () const |
| Number of points in the path (not the same as its length). More... | |
| virtual void | swap (PixPath &vpp) |
| Swap the contents of two PixPaths. More... | |
| virtual void | clear () |
| Discard all points. More... | |
| const_iterator | begin () const |
| Return an iterator pointing to the first point in the path. More... | |
| const_iterator | end () const |
| Rtn iterator pointing to just beyond the last point in the path. More... | |
| const_reverse_iterator | rbegin () const |
| return a reverse-moving iterator to the last point in path More... | |
| const_reverse_iterator | rend () const |
| return one-before-first iterator, in symmetry with end(). More... | |
| virtual PixPath & | append (const_iterator begin, const_iterator end) |
| Append a range from a given other path to the end of this path. More... | |
| virtual PixPath & | append (const PixPath &suffix) |
| Append the given path to the tail of this path; overwrites. More... | |
| virtual int | append_no_overlap (const PixPath &suffix) |
| Like append(), with extra avoid-the-duplicates fuss; overwrites. More... | |
| PixPath | subrange (unsigned, unsigned) const |
| Returns a subrange of this PixPath object. More... | |
| PixPath | prefix (unsigned postlast) const |
| Variation on subrange: return a prefix of this path (by value) More... | |
| PixPath | suffix (unsigned first) const |
| Variation on subrange: return a suffix of this path (by value) More... | |
| bool | self_intersect (PixPoint *where=00) const |
| Reveal whether the path has any self-intersections. More... | |
| bool | connected8 (bool emit_verbose_debug_output=false) const |
| Is the path all connected, using 8-connectivity? More... | |
| PixPoint | front () const |
| Return (by value) the first point in the path. More... | |
| PixPoint | back () const |
| Return (by value) the last point in the path. More... | |
| virtual int | arclength (std::vector< float > *) const |
| Return a vector of arclengths along the polygonal path. More... | |
| virtual float | arclength () const |
| compute and return polygonal path length of this path More... | |
| std::string | str (const std::string &separator="\n") const |
| Return the path as an ASCII string. More... | |
| int | save (const std::string &filename) const |
| Saves the path to an ASCII file, returns NO_ERROR or ERROR. More... | |
| bool | operator== (const PixPath &) const |
| Compare PixPaths; true iff the sequence of points is identical. More... | |
| bool | operator!= (const PixPath &other) const |
| Compare PixPaths; true iff the sequence of points differs. More... | |
| PixPath | operator+ (const PixPath &) const |
| Add, element-by-element, two PixPaths of the same length. More... | |
| virtual PixPoint | boundbox_min_min () const |
| Return the corner point of a bounding box, with min x and y. More... | |
| virtual PixPoint | boundbox_max_max () const |
| Similar to boundbox_min_min() but returns maximum x, y coords. More... | |
| bool | boundbox_within_boundbox (const PixPath &outer) const |
| Test whether the axis-aligned bounding box of this path lies within the axis-aligned bounding box of the given path. More... | |
| bool | so_boundbox_holds_within (const PixPoint &q) const |
| sort of like boundbox_within_boundbox but works on a single point More... | |
| unsigned | hits (const PixPoint &query_point) const |
| Return number of times (maybe 0) the path hits a query point. More... | |
| unsigned | hits (const PixPath &query_path) const |
| return number of common points between query_path and this path More... | |
| PixPoint | nearest (const PixPoint &, const_iterator *q=00) const |
| Return the PixPath member closest to a given query point. More... | |
| PixPoint | nearest (const kjb::Vector2 &, const_iterator *q=00) const |
| Return the PixPath member closest to the given real xy coordinates. More... | |
| PixPath & | ow_reverse () |
| Reverse the order of the points in the path (overwriting!) More... | |
| PixPath | reverse () const |
| return a copy of this list after reversing the front-back order. More... | |
| int | cubic_fit (std::vector< float > *x, std::vector< float > *y, int ref=0) const |
| Fit a cubic polynomial to the given list of x and y points. More... | |
| PixPath | interpolate (bool forbid_self_intersection=false) const |
| This interpolates pixels between unconnected pixels. More... | |
| PixPath | cull_redundant_points () const |
| Remove "unnecessary" points (ones that can be bresenham interpolated) More... | |
| PixPath | merge_redundant_slopes () const |
| return a path with interior points removed but preserve all slopes. More... | |
| PixPath | expel (const_iterator) const |
| Duplicate this path, except that we omit the indicated point. More... | |
| PixPath | expel (size_t index_of_unwanted_point) const |
| Duplicate this path, except we omit the point with given index. More... | |
| virtual float | hausdorff_distance (const PixPath &that) const |
| Compute the Hausdorff metric between two sets of points. More... | |
| float | closest_pair (const_iterator *pa=0, const_iterator *pb=0) const |
| Find the distance between closest pair of points, ignoring adjacency. More... | |
| float | closest_adjacent_pair (const_iterator *pa=0) const |
| Find a pair of adjacent points at least as close as any other. More... | |
| bool | has_subsequence (const PixPath &subseq) const |
| tests whether a given path is a subsequence of this path More... | |
| double | angle_at (unsigned) const |
| Compute included angle at some interior point in a path. More... | |
| PixPoint::Integer | bracket_cross_at (unsigned index) const |
| cross product of line segs (index-1,index+1) x (index,index+1) More... | |
| double | heading_shift_at (unsigned index) const |
| compute shift in "heading" angle at an interior point More... | |
| bool | intersect_at_with (unsigned preindex1, unsigned preindex2, unsigned *endpoint_intersector_index=00) const |
| Test whether two segments of this path intersect. More... | |
| bool | do_segments_intersect (unsigned *s1=00, unsigned *s2=00, unsigned *count=00) const |
| quadratic time test whether any 2 path segments cross each other More... | |
| unsigned | longest_segment (float *length=00) const |
| return index of first point of longest segment More... | |
| kjb::Vector2 | centroid () const |
| return the "mean" of the points (nonempty, none may be unused) More... | |
| unsigned | member_near_centroid () const |
| return index of a member point nearest centroid() (qv) More... | |
Static Public Member Functions | |
| static PolyPath | construct_from_vertices (const PixPath &vertices) |
| static ctor: build polygonal path from a sequence of vertices More... | |
| static PolyPath | construct_from_path (const PixPath &path) |
| static ctor: reconstruct a path with extra information More... | |
| Static Public Member Functions inherited from kjb::qd::PixPath | |
| static PixPath | reserve (size_t potential_size=0) |
| named ctor creates an empty path but reserves some memory for it More... | |
| static PixPath | load (const std::string &filename) |
| named ctor loads path coordinates from an ASCII file More... | |
| static PixPath | fenceposts (const PixPoint &pt_a, const PixPoint &pt_b, size_t sz) |
| named ctor makes a path of evenly spaced points from a to b More... | |
| static PixPath | parse (const std::string &coords) |
| named ctor builds from string-format list of coordinates More... | |
Additional Inherited Members | |
| Public Types inherited from kjb::qd::PixPath | |
| typedef const PixPoint & | const_reference |
| Reference to an element – required to use std::back_inserter(). More... | |
| typedef PixPoint | value_type |
| Element type – required to use std::back_inserter() in c++11. More... | |
| typedef VecPP::const_iterator | const_iterator |
| constant iterator through PixPath points More... | |
| typedef VecPP::const_reverse_iterator | const_reverse_iterator |
| constant reverse iterator through PixPath points More... | |
| Protected Member Functions inherited from kjb::qd::PixPath | |
| PixPath () | |
| Default ctor starts as empty, and you can push points onto it. More... | |
| PixPath (size_t potential_size) | |
| ctor receives the size to reserve More... | |
| PixPath (const std::string &) | |
| ctor to load from an ASCII file More... | |
| PixPath (const PixPoint &, const PixPoint &, size_t) | |
| ctor makes evenly spaced points between termini More... | |
| PixPath (const std::string &, int) | |
| ctor that parses a string of characters More... | |
represents an open polygonal path with a tangent at each point
The PixPath interface to this object represents the 8-connected "view" of the path. If you want to access the vertices, use the get_vertices() method. If you want to test whether a certain location along the path is a vertex, use the is_a_vertex() predicate.
This class defines a tangent at each point along the connected path. Each tangent is represented as a radial unit vector, i.e., it could lie anywhere on the unit circle. The direction points generally from the lower-numbered vertices to the higher-numbered vertices. Thus the tangent at location 0 is a unit vector pointing from vertex 0 to vertex 1.
Tangents at non-vertex locations are defined similarly: each non-vertex location is bookended by vertices v, w, and the tangent goes in the direction from v to w. This is one reason why the input vertices must be distinct.
We also define a value that will serve as "tangent" at the vertices themselves. Let v be an interior vertex and let u, w be its predecessor and successor vertices. Let r be a unit vector in the (u,v) direction and let s be a unit vector in the (v, w) direction. We define the "tangent" at v therefore to be a unit vector in the (r+s) direction. We defined the "tangent" at the first vertex above, and for the last vertex the definition is similar.
static ctor: reconstruct a path with extra information
static ctor: build polygonal path from a sequence of vertices
| Illegal_argument | if input has a repeated pt. or a 180-deg bend. |
| int kjb::qd::PolyPath::debug_print | ( | std::ostream & | os | ) | const |
print the inner state of a PolyPath object to a stream
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inline |
provide read-only access to the sequence of polygon vertices
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inline |
test whether the point at a given index is a polygonal vertex
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inline |
access unit vector at a point along path, spec by const_iterator
| i | const_iterator to a point in the path |
On points that are NOT vertices, the output represents a ray passing from the nearest vertex prior to this path location, through the nearest vertex subsequent to this path location. Thus, it is directed and the output (as a unit vector) can potentially lie in any of the four quadrants. If you prefer an axial direction rather than a radial direction, you might find these other functions useful:
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inline |
access unit vector at a point along path, specified by index
1.8.6