java.awt.geom
Class FlatteningPathIterator
- PathIterator
A PathIterator for approximating curved path segments by sequences
of straight lines. Instances of this class will only return
segments of type
PathIterator.SEG_MOVETO,
PathIterator.SEG_LINETO, and
PathIterator.SEG_CLOSE.
The accuracy of the approximation is determined by two
parameters:
- The flatness is a threshold value for deciding when
a curved segment is consided flat enough for being approximated by
a single straight line. Flatness is defined as the maximal distance
of a curve control point to the straight line that connects the
curve start and end. A lower flatness threshold means a closer
approximation. See
QuadCurve2D.getFlatness() and CubicCurve2D.getFlatness() for drawings which illustrate the
meaning of flatness. - The recursion limit imposes an upper bound for how often
a curved segment gets subdivided. A limit of n means that
for each individual quadratic and cubic Bézier spline
segment, at most 2n
PathIterator.SEG_LINETO segments will be created.
Memory Efficiency: The memory consumption grows linearly
with the recursion limit. Neither the
flatness parameter nor
the number of segments in the flattened path will affect the memory
consumption.
Thread Safety: Multiple threads can safely work on
separate instances of this class. However, multiple threads should
not concurrently access the same instance, as no synchronization is
performed.
int | currentSegment(double[] coords)- Returns the coordinates of the next point(s), as well as the type of
line segment.
|
int | currentSegment(float[] coords)- Returns the coordinates of the next point(s), as well as the type of
line segment.
|
double | getFlatness()- Returns the maximally acceptable flatness.
|
int | getRecursionLimit()- Returns the maximum number of recursive curve subdivisions.
|
int | getWindingRule()- Returns the winding rule to determine which points are inside this path.
|
boolean | isDone()- Tests if the iterator is exhausted.
|
void | next()- Advance to the next segment in the iteration.
|
clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait |
FlatteningPathIterator
public FlatteningPathIterator(PathIterator src,
double flatness) Constructs a new PathIterator for approximating an input
PathIterator with straight lines. The approximation works by
recursive subdivisons, until the specified flatness threshold is
not exceeded.
There will not be more than 10 nested recursion steps, which
means that a single
SEG_QUADTO or
SEG_CUBICTO segment is approximated by at most
2
10 = 1024 straight lines.
FlatteningPathIterator
public FlatteningPathIterator(PathIterator src,
double flatness,
int limit) Constructs a new PathIterator for approximating an input
PathIterator with straight lines. The approximation works by
recursive subdivisons, until the specified flatness threshold is
not exceeded. Additionally, the number of recursions is also
bound by the specified recursion limit.
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.
- currentSegment in interface PathIterator
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.
- currentSegment in interface PathIterator
coords - the array to place the point coordinates in
getFlatness
public double getFlatness()
Returns the maximally acceptable flatness.
getRecursionLimit
public int getRecursionLimit()
Returns the maximum number of recursive curve subdivisions.
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).
- isDone in interface PathIterator
- 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.
- next in interface PathIterator
FlatteningPathIterator.java -- Approximates curves by straight lines
Copyright (C) 2003 Free Software Foundation
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