FlatteningPathIterator
public interface PathIterator
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.
Modifier and Type | Field | Description |
---|---|---|
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. |
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. |
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. |
static final int |
SEG_MOVETO |
The segment type constant for a point that specifies the starting location for a new subpath. |
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. |
static final int |
WIND_EVEN_ODD |
The winding rule constant for specifying an even-odd rule for determining the interior of a path. |
static final int |
WIND_NON_ZERO |
The winding rule constant for specifying a non-zero rule for determining the interior of a path. |
Modifier and Type | Method | Description |
---|---|---|
int |
currentSegment |
Returns the coordinates and type of the current path segment in the iteration. |
int |
currentSegment |
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. |
@Native static final int WIND_EVEN_ODD
@Native static final int WIND_NON_ZERO
@Native static final int SEG_MOVETO
@Native static final int SEG_LINETO
@Native 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)^(n-m) C(n,m) = Combinations of n things, taken m at a time = n! / (m! * (n-m)!)
@Native 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)^(n-m) C(n,m) = Combinations of n things, taken m at a time = n! / (m! * (n-m)!)This form of curve is commonly known as a Bézier curve.
@Native static final int SEG_CLOSE
int getWindingRule()
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 methodint currentSegment(double[] coords)
coords
- an array that holds the data returned from this method
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Documentation extracted from Debian's OpenJDK Development Kit package.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/geom/PathIterator.html