org.apache.batik.ext.awt.geom
public class PathLength extends Object
PathLength is a utility class for calculating the length of a path, the location of a point at a particular length along the path, and the angle of the tangent to the path at a given length.
It uses a FlatteningPathIterator to create a flattened version of the Path. This means the values returned are not always exact (in fact, they rarely are), but in most cases they are reasonably accurate.
Nested Class Summary | |
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protected static class | PathLength.PathSegment
A single path segment in the flattened version of the path.
|
protected static class | PathLength.SingleSegmentPathIterator
A PathIterator that returns only the next path segment from
another PathIterator. |
Field Summary | |
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protected boolean | initialised
Whether this path been flattened yet. |
protected Shape | path
The path to use for calculations. |
protected float | pathLength
Cached copy of the path length. |
protected int[] | segmentIndexes
Array where the index is the index of the original path segment
and the value is the index of the first of the flattened segments
in segments that corresponds to that original path segment. |
protected List | segments
The list of flattened path segments. |
Constructor Summary | |
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PathLength(Shape path)
Creates a new PathLength object for the specified Shape. |
Method Summary | |
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float | angleAtLength(int index, float proportion)
Returns the slope of the path at the specified length. |
float | angleAtLength(float length)
Returns the slope of the path at the specified length. |
int | findUpperIndex(float length)
Returns the index of the path segment that bounds the specified
length along the path. |
float | getLengthAtSegment(int index)
Returns the length at the start of the segment given by the specified
index. |
int | getNumberOfSegments()
Returns the number of segments in the path. |
Shape | getPath()
Returns the path to use for calculations. |
protected void | initialise()
Flattens the path and determines the path length. |
float | lengthOfPath()
Returns the length of the path used by this PathLength object. |
Point2D | pointAtLength(int index, float proportion)
Returns the point that is the given proportion along the path segment
given by the specified index. |
Point2D | pointAtLength(float length)
Returns the point that is at the given length along the path. |
int | segmentAtLength(float length)
Returns the index of the segment at the given distance along the path. |
void | setPath(Shape v)
Sets the path to use for calculations. |
Parameters: path The Path (or Shape) to use.
Parameters: index The segment number proportion The proportion along the given segment
Returns: the angle in radians, in the range [-Math#PI, Math#PI].
Parameters: length The length along the path
Returns: the angle in radians, in the range [-Math#PI, Math#PI].
Parameters: length The length along the path
Returns: The path segment index, or -1 if there is not such segment
Returns: Path used in calculations.
Returns: The length of the path.
Parameters: length The length along the path
Returns: The point at the given length
Parameters: v Path to be used in calculations.