
Java™ Platform Standard Ed. 6 

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public interface PathIterator
The PathIterator
interface provides the mechanism
for objects that implement the Shape
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.
Shape
,
BasicStroke
Field Summary  

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  

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 

static final int WIND_EVEN_ODD
static final int WIND_NON_ZERO
static final int SEG_MOVETO
static final int SEG_LINETO
static final int SEG_QUADTO
(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)!)
static final int SEG_CUBICTO
(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.
static final int SEG_CLOSE
Method Detail 

int getWindingRule()
WIND_EVEN_ODD
,
WIND_NON_ZERO
boolean isDone()
true
if all the segments have
been read; false
otherwise.void next()
int currentSegment(float[] coords)
coords
 an array that holds the data returned from
this method
SEG_MOVETO
,
SEG_LINETO
,
SEG_QUADTO
,
SEG_CUBICTO
,
SEG_CLOSE
int currentSegment(double[] coords)
coords
 an array that holds the data returned from
this method
SEG_MOVETO
,
SEG_LINETO
,
SEG_QUADTO
,
SEG_CUBICTO
,
SEG_CLOSE

Java™ Platform Standard Ed. 6 

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Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.