java.awt.geom
Interface PathIterator
- FlatteningPathIterator
This interface provides a directed path over the boundary of a shape. The
path can contain 1st through 3rd order Bezier curves (lines, and quadratic
and cubic splines). A shape can have multiple disjoint paths via the
MOVETO directive, and can close a circular path back to the previos
MOVETO via the CLOSE directive.
static int | SEG_CLOSE - The current segment closes a loop by an implicit line to the previous
SEG_MOVETO coordinate.
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static int | SEG_CUBICTO - The current segment is a cubic parametric curve (more commonly known as
a Bezier curve).
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static int | SEG_LINETO - The current segment is a line.
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static int | SEG_MOVETO - Starts a new subpath.
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static int | SEG_QUADTO - The current segment is a quadratic parametric curve.
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static int | WIND_EVEN_ODD - The even-odd winding mode: a point is internal to the shape if a ray
from the point to infinity (in any direction) crosses an odd number of
segments.
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static int | WIND_NON_ZERO - The non-zero winding mode: a point is internal to the shape if a ray
from the point to infinity (in any direction) crosses a different number
of segments headed clockwise than those headed counterclockwise.
|
int | currentSegment(double[] coords) - Returns the coordinates of the next point(s), as well as the type of
line segment.
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int | currentSegment(float[] coords) - Returns the coordinates of the next point(s), as well as the type of
line segment.
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int | getWindingRule() - Returns the winding rule to determine which points are inside this path.
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boolean | isDone() - Tests if the iterator is exhausted.
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void | next() - Advance to the next segment in the iteration.
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SEG_CLOSE
public static final int SEG_CLOSE
The current segment closes a loop by an implicit line to the previous
SEG_MOVETO coordinate.
SEG_CUBICTO
public static final int SEG_CUBICTO
The current segment is a cubic parametric curve (more commonly known as
a Bezier curve). It is interpolated as t varies from 0 to 1 over the
current point (CP), first control point (P1), the second control point
(P2), and final interpolated control point (P3):
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)^(n-m)
C(n,m) = Combinations of n things, taken m at a time
= n! / (m! * (n-m)!)
SEG_LINETO
public static final int SEG_LINETO
The current segment is a line.
SEG_MOVETO
public static final int SEG_MOVETO
Starts a new subpath. There is no segment from the previous vertex.
SEG_QUADTO
public static final int SEG_QUADTO
The current segment is a quadratic parametric curve. It is interpolated
as t varies from 0 to 1 over the current point (CP), first control point
(P1), and final interpolated control point (P2):
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)^(n-m)
C(n,m) = Combinations of n things, taken m at a time
= n! / (m! * (n-m)!)
WIND_EVEN_ODD
public static final int WIND_EVEN_ODD
The even-odd winding mode: a point is internal to the shape if a ray
from the point to infinity (in any direction) crosses an odd number of
segments.
WIND_NON_ZERO
public static final int WIND_NON_ZERO
The non-zero winding mode: a point is internal to the shape if a ray
from the point to infinity (in any direction) crosses a different number
of segments headed clockwise than those headed counterclockwise.
currentSegment
public int currentSegment(double[] coords)
Returns the coordinates of the next point(s), as well as the type of
line segment. The input array must be at least a double[6], to accomodate
up to three (x,y) point pairs (although if you know the iterator is
flat, you can probably get by with a double[2]). If the returned type is
SEG_MOVETO or SEG_LINETO, the first point in the array is modified; if
the returned type is SEG_QUADTO, the first two points are modified; if
the returned type is SEG_CUBICTO, all three points are modified; and if
the returned type is SEG_CLOSE, the array is untouched.
coords
- the array to place the point coordinates in
currentSegment
public int currentSegment(float[] coords)
Returns the coordinates of the next point(s), as well as the type of
line segment. The input array must be at least a float[6], to accomodate
up to three (x,y) point pairs (although if you know the iterator is
flat, you can probably get by with a float[2]). If the returned type is
SEG_MOVETO or SEG_LINETO, the first point in the array is modified; if
the returned type is SEG_QUADTO, the first two points are modified; if
the returned type is SEG_CUBICTO, all three points are modified; and if
the returned type is SEG_CLOSE, the array is untouched.
coords
- the array to place the point coordinates in
getWindingRule
public int getWindingRule()
Returns the winding rule to determine which points are inside this path.
isDone
public boolean isDone()
Tests if the iterator is exhausted. If this returns true, currentSegment
and next may throw a NoSuchElementException (although this is not
required).
- true if the iteration is complete
next
public void next()
Advance to the next segment in the iteration. It is not specified what
this does if called when isDone() returns true.
PathIterator.java -- describes a shape by iterating over its vertices
Copyright (C) 2000, 2002, 2003 Free Software Foundation
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