API Reference: Path

The Path class represents complex, compound geometric paths composed of straight line segments, quadratic curves, and cubic curves.

Note: For building new paths, it is highly recommended to use PathBuilder instead of calling methods directly on Path. PathBuilder provides a better fluent API and ensures the resulting Path is immutable.

Building a Path (Static Factories)

While PathBuilder is preferred for complex paths, Path offers efficient static factories for common shapes.

• makeRect(rect): Creates a path from a rectangle.
• makeOval(rect): Creates a path from an oval.
• makeCircle(x, y, radius): Creates a path from a circle.
• makeRRect(rrect): Creates a path from a rounded rectangle.
• makeLine(p1, p2): Creates a path from a single line segment.
• makePolygon(points, closed): Creates a path from a sequence of points.
• makeFromSVGString(svgString): Parses an SVG path string (e.g., "M10 10 L50 50 Z").

Path Information & Metrics

• getBounds(): Returns the conservative bounding box (fast, cached).
• computeTightBounds(): Returns the precise bounding box (slower).
• isEmpty(): Returns true if the path contains no verbs.
• isConvex(): Returns true if the path defines a convex shape.
• isRect(): Returns the Rect if the path represents a simple rectangle, or null.
• isOval(): Returns the bounding Rect if the path is an oval, or null.
• isFinite(): Returns true if all points in the path are finite.

Hit Testing

• contains(x, y): Returns true if the specified point is inside the path (based on the current Fill Type).
• conservativelyContainsRect(rect): Returns true if the rect is definitely inside the path (fast rejection test).

Boolean Operations

Paths can be combined using logical operations. These create a new Path object.

Path result = Path.makeCombining(pathA, pathB, PathOp.INTERSECT);

Available PathOps:

• DIFFERENCE: A - B
• INTERSECT: A & B
• UNION: A | B
• XOR: (A | B) - (A & B)
• REVERSE_DIFFERENCE: B - A

Transformations & Modification

These methods return a new Path instance with the transformation applied.

• makeTransform(matrix): Applies a Matrix33 to all points in the path.
• makeOffset(dx, dy): Translates the path.
• makeScale(s): Scales the path.

Interpolation (Morphing)

You can interpolate between two compatible paths (useful for animations).

// Interpolate 50% between pathA and pathB
if (pathA.isInterpolatable(pathB)) {
    Path midPath = pathA.makeInterpolate(pathB, 0.5f);
}

Serialization

• serializeToBytes(): Serializes the path to a byte array.
• makeFromBytes(bytes): Reconstructs a path from bytes.
• dump(): Prints the path structure to standard output (for debugging).

Measuring and Iteration

• PathMeasure: Used to calculate the length of a path and find positions/tangents along its length.
• PathSegmentIterator: Allows you to iterate over the individual verbs and points that make up the path.

Example

Path path = new Path()
    .moveTo(10, 10)
    .lineTo(100, 10)
    .lineTo(100, 100)
    .quadTo(50, 150, 10, 100)
    .closePath();

canvas.drawPath(path, paint);

Fill Type

The fill type determines which areas are considered "inside" the path for filling operations.

• WINDING (Default): Uses the winding number rule.
• EVEN_ODD: Uses the even-odd rule.
• INVERSE_WINDING: Inverts the winding rule (fills outside).
• INVERSE_EVEN_ODD: Inverts the even-odd rule.

Visual Example

See examples/scenes/src/PathsScene.java for examples of creating, modifying, and combining paths.