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)