
 All Known Implementing Classes:
FlatteningPathIterator
public interface PathIterator
ThePathIterator
interface provides the mechanism for objects that implement theShape
interface to return the geometry of their boundary by allowing a caller to retrieve the path of that boundary a segment at a time. This interface allows these objects to retrieve the path of their boundary a segment at a time by using 1st through 3rd order Bézier curves, which are lines and quadratic or cubic Bézier splines.Multiple subpaths can be expressed by using a "MOVETO" segment to create a discontinuity in the geometry to move from the end of one subpath to the beginning of the next.
Each subpath can be closed manually by ending the last segment in the subpath on the same coordinate as the beginning "MOVETO" segment for that subpath or by using a "CLOSE" segment to append a line segment from the last point back to the first. Be aware that manually closing an outline as opposed to using a "CLOSE" segment to close the path might result in different line style decorations being used at the end points of the subpath. For example, the
BasicStroke
object uses a line "JOIN" decoration to connect the first and last points if a "CLOSE" segment is encountered, whereas simply ending the path on the same coordinate as the beginning coordinate results in line "CAP" decorations being used at the ends. See Also:
Shape
,BasicStroke


Field Summary
Fields Modifier and Type Field Description static int
SEG_CLOSE
The segment type constant that specifies that the preceding subpath should be closed by appending a line segment back to the point corresponding to the most recent SEG_MOVETO.static int
SEG_CUBICTO
The segment type constant for the set of 3 points that specify a cubic parametric curve to be drawn from the most recently specified point.static int
SEG_LINETO
The segment type constant for a point that specifies the end point of a line to be drawn from the most recently specified point.static int
SEG_MOVETO
The segment type constant for a point that specifies the starting location for a new subpath.static int
SEG_QUADTO
The segment type constant for the pair of points that specify a quadratic parametric curve to be drawn from the most recently specified point.static int
WIND_EVEN_ODD
The winding rule constant for specifying an evenodd rule for determining the interior of a path.static int
WIND_NON_ZERO
The winding rule constant for specifying a nonzero rule for determining the interior of a path.

Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description int
currentSegment(double[] coords)
Returns the coordinates and type of the current path segment in the iteration.int
currentSegment(float[] coords)
Returns the coordinates and type of the current path segment in the iteration.int
getWindingRule()
Returns the winding rule for determining the interior of the path.boolean
isDone()
Tests if the iteration is complete.void
next()
Moves the iterator to the next segment of the path forwards along the primary direction of traversal as long as there are more points in that direction.



Field Detail

WIND_EVEN_ODD
@Native static final int WIND_EVEN_ODD
The winding rule constant for specifying an evenodd rule for determining the interior of a path. The evenodd rule specifies that a point lies inside the path if a ray drawn in any direction from that point to infinity is crossed by path segments an odd number of times. See Also:
 Constant Field Values

WIND_NON_ZERO
@Native static final int WIND_NON_ZERO
The winding rule constant for specifying a nonzero rule for determining the interior of a path. The nonzero rule specifies that a point lies inside the path if a ray drawn in any direction from that point to infinity is crossed by path segments a different number of times in the counterclockwise direction than the clockwise direction. See Also:
 Constant Field Values

SEG_MOVETO
@Native static final int SEG_MOVETO
The segment type constant for a point that specifies the starting location for a new subpath. See Also:
 Constant Field Values

SEG_LINETO
@Native static final int SEG_LINETO
The segment type constant for a point that specifies the end point of a line to be drawn from the most recently specified point. See Also:
 Constant Field Values

SEG_QUADTO
@Native static final int SEG_QUADTO
The segment type constant for the pair of points that specify a quadratic parametric curve to be drawn from the most recently specified point. The curve is interpolated by solving the parametric control equation in the range(t=[0..1])
using the most recently specified (current) point (CP), the first control point (P1), and the final interpolated control point (P2). The parametric control equation for this curve is:P(t) = B(2,0)*CP + B(2,1)*P1 + B(2,2)*P2 0 <= t <= 1 B(n,m) = mth coefficient of nth degree Bernstein polynomial = C(n,m) * t^(m) * (1  t)^(nm) C(n,m) = Combinations of n things, taken m at a time = n! / (m! * (nm)!)
 See Also:
 Constant Field Values

SEG_CUBICTO
@Native static final int SEG_CUBICTO
The segment type constant for the set of 3 points that specify a cubic parametric curve to be drawn from the most recently specified point. The curve is interpolated by solving the parametric control equation in the range(t=[0..1])
using the most recently specified (current) point (CP), the first control point (P1), the second control point (P2), and the final interpolated control point (P3). The parametric control equation for this curve is:P(t) = B(3,0)*CP + B(3,1)*P1 + B(3,2)*P2 + B(3,3)*P3 0 <= t <= 1 B(n,m) = mth coefficient of nth degree Bernstein polynomial = C(n,m) * t^(m) * (1  t)^(nm) C(n,m) = Combinations of n things, taken m at a time = n! / (m! * (nm)!)
This form of curve is commonly known as a Bézier curve. See Also:
 Constant Field Values

SEG_CLOSE
@Native static final int SEG_CLOSE
The segment type constant that specifies that the preceding subpath should be closed by appending a line segment back to the point corresponding to the most recent SEG_MOVETO. See Also:
 Constant Field Values


Method Detail

getWindingRule
int getWindingRule()
Returns the winding rule for determining the interior of the path. Returns:
 the winding rule.
 See Also:
WIND_EVEN_ODD
,WIND_NON_ZERO

isDone
boolean isDone()
Tests if the iteration is complete. Returns:
true
if all the segments have been read;false
otherwise.

next
void next()
Moves the iterator to the next segment of the path forwards along the primary direction of traversal as long as there are more points in that direction.

currentSegment
int currentSegment(float[] coords)
Returns the coordinates and type of the current path segment in the iteration. The return value is the pathsegment type: SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. A float array of length 6 must be passed in and can be used to store the coordinates of the point(s). Each point is stored as a pair of float x,y coordinates. SEG_MOVETO and SEG_LINETO types returns one point, SEG_QUADTO returns two points, SEG_CUBICTO returns 3 points and SEG_CLOSE does not return any points. Parameters:
coords
 an array that holds the data returned from this method Returns:
 the pathsegment type of the current path segment.
 See Also:
SEG_MOVETO
,SEG_LINETO
,SEG_QUADTO
,SEG_CUBICTO
,SEG_CLOSE

currentSegment
int currentSegment(double[] coords)
Returns the coordinates and type of the current path segment in the iteration. The return value is the pathsegment type: SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. A double array of length 6 must be passed in and can be used to store the coordinates of the point(s). Each point is stored as a pair of double x,y coordinates. SEG_MOVETO and SEG_LINETO types returns one point, SEG_QUADTO returns two points, SEG_CUBICTO returns 3 points and SEG_CLOSE does not return any points. Parameters:
coords
 an array that holds the data returned from this method Returns:
 the pathsegment type of the current path segment.
 See Also:
SEG_MOVETO
,SEG_LINETO
,SEG_QUADTO
,SEG_CUBICTO
,SEG_CLOSE

