API Reference: PathMeasure

PathMeasure is used to calculate the length of a path, and to find the position and tangent at any given distance along the path.

Overview

A PathMeasure object is initialized with a Path. It iterates through the contours of the path. If the path has multiple contours, you can move to the next one using nextContour().

Constructors

• new PathMeasure(): Creates an empty PathMeasure.
• new PathMeasure(path): Initializes with the specified path.
• new PathMeasure(path, forceClosed): If forceClosed is true, the path is treated as if it were closed, even if it isn't.
• new PathMeasure(path, forceClosed, resScale): resScale controls the precision of the measurement (default is 1.0).

Methods

State Management

• setPath(path, forceClosed): Resets the measure with a new path.
• nextContour(): Moves to the next contour in the path. Returns true if one exists.
• isClosed(): Returns true if the current contour is closed.

Measurements

• getLength(): Returns the total length of the current contour.
• getPosition(distance): Returns the Point at the specified distance along the path.
• getTangent(distance): Returns the tangent (as a Point vector) at the specified distance.
• getRSXform(distance): Returns the RSXform at the specified distance.
• getMatrix(distance, getPosition, getTangent): Returns a Matrix33 representing the position and/or tangent at the distance.

Extraction

• getSegment(startD, endD, dst, startWithMoveTo): Returns the segment of the path between startD and endD into the provided PathBuilder.

Example

Path path = Path.makeCircle(100, 100, 50);
PathMeasure measure = new PathMeasure(path);

float length = measure.getLength();
Point pos = measure.getPosition(length / 2); // Get point halfway around
Point tan = measure.getTangent(length / 2);   // Get direction at that point