Package ch.bailu.gtk.gsk

Klasse PathPoint

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.type.Record
ch.bailu.gtk.gsk.PathPoint
Alle implementierten Schnittstellen:
PointerInterface
public class PathPoint extends Record
An opaque type representing a point on a path.

It can be queried for properties of the path at that point,
such as its tangent or its curvature.

To obtain a `GskPathPoint`, use [method@Gsk.Path.get_closest_point],
[method@Gsk.Path.get_start_point], [method@Gsk.Path.get_end_point]
or [method@Gsk.PathMeasure.get_point].

Note that `GskPathPoint` structs are meant to be stack-allocated,
and don't hold a reference to the path object they are obtained from.
It is the callers responsibility to keep a reference to the path
as long as the `GskPathPoint` is used.

https://docs.gtk.org/gsk4/struct.PathPoint.html

  • Konstruktordetails

  • Methodendetails

    • getClassHandler

      public static ClassHandler getClassHandler()

    • compare

      public int compare(@Nonnull PathPoint point2)
      Returns whether @point1 is before or after @point2.
      Parameter:
      point2 - another path point
      Gibt zurück:
      -1 if @point1 is before @point2, 1 if @point1 is after @point2, 0 if they are equal

    • copy

      public PathPoint copy()
      Copies a path point.
      Gibt zurück:
      the copied point

    • equal

      public boolean equal(@Nonnull PathPoint point2)
      Returns whether the two path points refer to the same
      location on all paths.

      Note that the start- and endpoint of a closed contour
      will compare nonequal according to this definition.
      Use [method@Gsk.Path.is_closed] to find out if the
      start- and endpoint of a concrete path refer to the
      same location.
      Parameter:
      point2 - another path point
      Gibt zurück:
      true if @point1 and @point2 are equal

    • free

      public void free()
      Frees a path point copied by [method@Gsk.PathPoint.copy].

    • getCurvature

      public float getCurvature(@Nonnull Path path, int direction, @Nullable Point center)
      Calculates the curvature of the path at the point.

      Optionally, returns the center of the osculating circle as well.
      The curvature is the inverse of the radius of the osculating circle.

      Lines have a curvature of zero (indicating an osculating circle of
      infinite radius). In this case, the @center is not modified.

      Circles with a radius of zero have `INFINITY` as curvature

      Note that certain points on a path may not have a single curvature,
      such as sharp turns. At such points, there are two curvatures — the
      (limit of) the curvature of the path going into the point, and the
      (limit of) the curvature of the path coming out of it. The @direction
      argument lets you choose which one to get.

      <picture>
      <source srcset="curvature-dark.png" media="(prefers-color-scheme: dark)">
      <img alt="Osculating circle" src="curvature-light.png">
      </picture>
      Parameter:
      path - the path that @point is on
      direction - the direction for which to return the curvature
      center - return location for the center of the osculating circle
      Gibt zurück:
      the curvature of the path at the given point

    • getDistance

      public float getDistance(@Nonnull PathMeasure measure)
      Returns the distance from the beginning of the path
      to the point.
      Parameter:
      measure - a path measure for the path
      Gibt zurück:
      the distance of @point

    • getPosition

      public void getPosition(@Nonnull Path path, @Nonnull Point position)
      Gets the position of the point.
      Parameter:
      path - the path that @point is on
      position - Return location for the coordinates of the point

    • getRotation

      public float getRotation(@Nonnull Path path, int direction)
      Gets the direction of the tangent at a given point.

      This is a convenience variant of [method@Gsk.PathPoint.get_tangent]
      that returns the angle between the tangent and the X axis. The angle
      can e.g. be used in
      [gtk_snapshot_rotate()](../gtk4/method.Snapshot.rotate.html).
      Parameter:
      path - the path that @point is on
      direction - the direction for which to return the rotation
      Gibt zurück:
      the angle between the tangent and the X axis, in degrees

    • getTangent

      public void getTangent(@Nonnull Path path, int direction, @Nonnull Vec2 tangent)
      Gets the tangent of the path at the point.

      Note that certain points on a path may not have a single
      tangent, such as sharp turns. At such points, there are
      two tangents — the direction of the path going into the
      point, and the direction coming out of it. The @direction
      argument lets you choose which one to get.

      If the path is just a single point (e.g. a circle with
      radius zero), then the tangent is set to `0, 0`.

      If you want to orient something in the direction of the
      path, [method@Gsk.PathPoint.get_rotation] may be more
      convenient to use.
      Parameter:
      path - the path that @point is on
      direction - the direction for which to return the tangent
      tangent - Return location for the tangent at the point

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()