NAME¶
PointObj, LineObj, BoxObj, MultiLineObj, FillPolygonObj, Extent - helper classes
that manage geometric information for structured graphics
SYNOPSIS¶
#include <Unidraw/Graphic/geomobjs.h>
DESCRIPTION¶
Unidraw defines several helper classes that store and manage geometric
information. Structured graphics objects may use these helper classes to
support their semantics. PointObj stores a point, LineObj stores two points,
and MultiLineObj stores any number of points. BoxObj and FillPolygonObj define
rectangular and polygonal areas, respectively. Extent stores extent
information, that is, the lower left corner and center of a bounding box plus
a fixed amount of extra space around the bounding box. All these classes
provide operations for computing geometric information.
POINTOBJ PUBLIC OPERATIONS¶
- PointObj(Coord = 0, Coord = 0)
- PointObj(PointObj*)
- Construct a PointObj, supplying either two Coords or
another PointObj to specify the instance's coordinates, which are stored
in its _x and _y public members.
- float Distance(PointObj&)
- Return the distance between this and the given
PointObj.
LINEOBJ PUBLIC OPERATIONS¶
- LineObj(Coord = 0, Coord = 0, Coord = 0, Coord =
0)
- LineObj(LineObj*)
- Construct a LineObj, supplying either two coordinate pairs
or another LineObj to specify the instance's endpoints, which are stored
in its _p1 and _p2 public members.
- boolean Contains(PointObj&)
- boolean Intersects(LineObj&)
- Return whether this contains the given point and
intersects the given line, respectively.
- int Same(PointObj& p1, PointObj& p2)
- A helper function used in Intersects. Same returns a
positive value if p1 and p2 fall on the same side of the
line, 0 if both points fall on the line, or a negative value if the points
are on opposite sides of the line.
BOXOBJ PUBLIC OPERATIONS¶
- BoxObj(Coord = 0, Coord = 0, Coord = 0, Coord =
0)
- BoxObj(BoxObj*)
- Construct a BoxObj, supplying either two coordinate pairs
or another BoxObj to specify the instance's bottom-left and top-right
corners, which are stored in its _left, _bottom,
_right, and _top public members.
- boolean Contains(PointObj&)
- boolean Intersects(BoxObj&)
- boolean Intersects(LineObj&)
- Return whether this contains the given point and
intersects the given box or line, respectively.
- BoxObj operator - (BoxObj&)
- BoxObj operator + (BoxObj&)
- Compute the intersection (-) or union (+) of this
and the given box, returning the result. These operations do not affect
this or their argument.
- boolean Within(BoxObj&)
- Return true if this falls completely within
the given box. Within will also return true if the boxes are
identical.
MULTILINEOBJ PUBLIC OPERATIONS¶
- MultiLineObj(Coord* = nil, Coord* = nil, int =
0)
- Create a MultiLineObj, optionally supplying coordinate
arrays (and their size) that define the vertices of the multiline. The
MultiLineObj does not copy these arrays but stores them directly.
The MultiLineObj stores this information in its _x, _y, and
_count public members.
- void GetBox(BoxObj&)
- Calculate the bounding box circumscribing the
MultiLineObj's vertices and store it in the argument.
- boolean Contains(PointObj&)
- boolean Intersects(BoxObj&)
- boolean Intersects(LineObj&)
- Return whether this contains the given point and
intersects the given box or line, respectively.
- boolean Within(BoxObj&)
- Return true if this falls completely within
the MultiLineObj's bounding box. Within will also return true if
the boxes are identical.
- void SplineToMultiLine(Coord* cpx, Coord* cpy, int
count)
- void ClosedSplineToMultiLine(Coord* cpx, Coord* cpy, int
count)
- Linearize the open or closed B-Spline defined by the given
set of control points and store the result in this. These
operations store the linearized result in internal buffers and assign the
addresses of these buffers to _x and _y; they do not
delete _x and _y if they are non-nil prior to
assignment.
MULTILINEOBJ PROTECTED OPERATIONS¶
- void GrowBuf()
- Increase the size of the internal buffers used to store
linearized splines.
- boolean CanApproxWithLine(
- double x0, double, y0,
- double x1, double y1,
- double x2, double y2
- )
-
Return whether two connected line segments defined by the given three points
can be approximated visually with a single line between the
endpoints.
- void AddLine(double x0, double y0, double x1, double
y1)
- Add a line to the internal buffer of vertices.
- void AddBezierArc(
- double x0, double y0, double x1, double y1,
- double x2, double y2, double x3, double y3
- )
-
Add lines approximating the appearance of a Bezier arc defined by the given
points to the internal buffer of vertices.
- void CalcSection(
- Coord cminus1x, Coord cminus1y, Coord cx, Coord
cy,
- Coord cplus1x, Coord cplus1y, Coord cplus2x, Coord
cplus2y
- )
-
Add a Bezier arc to the internal buffer of vertices based on a series of
four B-spline control points, the one before and the two after ( cx,
cy).
FILLPOLYGONOBJ PUBLIC OPERATIONS¶
- FillPolygonObj(Coord* = nil, Coord* = nil, int =
0)
- Create a new FillPolygonObj, optionally specifying its
vertices. If vertices are supplied, then the constructor uses Normalize
(described below) to store a normalized set of vertices in the
FillPolygonObj's _normx, _normy, and _normCount
public members. FillPolygonObj is a subclass of MultiLineObj; thus it
stores the constructor arguments in its _x, _y, and
_count public members.
- virtual ~FillPolygonObj()
- The destructor deletes the _normx and _normy
arrays.
- boolean Contains(PointObj&)
- boolean Intersects(BoxObj&)
- boolean Intersects(LineObj&)
- Return whether this contains the given point and
intersects the given box or line, respectively.
FILLPOLYGONOBJ PROTECTED OPERATIONS¶
- void Normalize()
- Copy the vertices defined by _x, _y, and
_count into _normx, _normy, and _normCount
such that ( _normx[0], _normy[0]) is the lower-leftmost vertex and
there are no redundant vertices.
EXTENT PUBLIC OPERATIONS¶
- Extent(
- float left = 0, float bottom = 0,
- float cx = 0, float cy = 0, float tol = 0
- )
- Extent(Extent&)
- Construct a new Extent, optionally supplying its parameters
explicitly or providing a existing Extent to copy. The parameters are
stored in the Extent's _left, _bottom, _cx,
_cy, and _tol public members.
- boolean Undefined()
- Return whether the extent is undefined, that is, if
(_left, _bottom) and (_cx, _cy) are the same
point.
- boolean Within(Extent&)
- Return true if the given extent circumscribes
this. Within will also return true if the extents are
identical.
- void Merge(Extent&)
- Enlarge this extent to subsume area of the given
extent.
SEE ALSO¶
Graphic(3U)