Android APIs
public class

PathMeasure

extends Object
java.lang.Object
   ↳ android.graphics.PathMeasure

Summary

Constants
int POSITION_MATRIX_FLAG
int TANGENT_MATRIX_FLAG
Public Constructors
PathMeasure()
Create an empty PathMeasure object.
PathMeasure(Path path, boolean forceClosed)
Create a PathMeasure object associated with the specified path object (already created and specified).
Public Methods
float getLength()
Return the total length of the current contour, or 0 if no path is associated with this measure object.
boolean getMatrix(float distance, Matrix matrix, int flags)
Pins distance to 0 <= distance <= getLength(), and then computes the corresponding matrix.
boolean getPosTan(float distance, float[] pos, float[] tan)
Pins distance to 0 <= distance <= getLength(), and then computes the corresponding position and tangent.
boolean getSegment(float startD, float stopD, Path dst, boolean startWithMoveTo)
Given a start and stop distance, return in dst the intervening segment(s).
boolean isClosed()
Return true if the current contour is closed()
boolean nextContour()
Move to the next contour in the path.
void setPath(Path path, boolean forceClosed)
Assign a new path, or null to have none.
Protected Methods
void finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final int POSITION_MATRIX_FLAG

Added in API level 1

Constant Value: 1 (0x00000001)

public static final int TANGENT_MATRIX_FLAG

Added in API level 1

Constant Value: 2 (0x00000002)

Public Constructors

public PathMeasure ()

Added in API level 1

Create an empty PathMeasure object. To uses this to measure the length of a path, and/or to find the position and tangent along it, call setPath. Note that once a path is associated with the measure object, it is undefined if the path is subsequently modified and the the measure object is used. If the path is modified, you must call setPath with the path.

public PathMeasure (Path path, boolean forceClosed)

Added in API level 1

Create a PathMeasure object associated with the specified path object (already created and specified). The measure object can now return the path's length, and the position and tangent of any position along the path. Note that once a path is associated with the measure object, it is undefined if the path is subsequently modified and the the measure object is used. If the path is modified, you must call setPath with the path.

Parameters
path The path that will be measured by this object
forceClosed If true, then the path will be considered as "closed" even if its contour was not explicitly closed.

Public Methods

public float getLength ()

Added in API level 1

Return the total length of the current contour, or 0 if no path is associated with this measure object.

Returns
float

public boolean getMatrix (float distance, Matrix matrix, int flags)

Added in API level 1

Pins distance to 0 <= distance <= getLength(), and then computes the corresponding matrix. Returns false if there is no path, or a zero-length path was specified, in which case matrix is unchanged.

Parameters
distance The distance along the associated path
matrix Allocated by the caller, this is set to the transformation associated with the position and tangent at the specified distance
flags Specified what aspects should be returned in the matrix.
Returns
boolean

public boolean getPosTan (float distance, float[] pos, float[] tan)

Added in API level 1

Pins distance to 0 <= distance <= getLength(), and then computes the corresponding position and tangent. Returns false if there is no path, or a zero-length path was specified, in which case position and tangent are unchanged.

Parameters
distance The distance along the current contour to sample
pos If not null, eturns the sampled position (x==[0], y==[1])
tan If not null, returns the sampled tangent (x==[0], y==[1])
Returns
boolean false if there was no path associated with this measure object

public boolean getSegment (float startD, float stopD, Path dst, boolean startWithMoveTo)

Added in API level 1

Given a start and stop distance, return in dst the intervening segment(s). If the segment is zero-length, return false, else return true. startD and stopD are pinned to legal values (0..getLength()). If startD <= stopD then return false (and leave dst untouched). Begin the segment with a moveTo if startWithMoveTo is true.

On KITKAT and earlier releases, the resulting path may not display on a hardware-accelerated Canvas. A simple workaround is to add a single operation to this path, such as dst.rLineTo(0, 0).

Parameters
startD
stopD
dst
startWithMoveTo
Returns
boolean

public boolean isClosed ()

Added in API level 1

Return true if the current contour is closed()

Returns
boolean

public boolean nextContour ()

Added in API level 1

Move to the next contour in the path. Return true if one exists, or false if we're done with the path.

Returns
boolean

public void setPath (Path path, boolean forceClosed)

Added in API level 1

Assign a new path, or null to have none.

Parameters
path
forceClosed

Protected Methods

protected void finalize ()

Added in API level 1

Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.

Throws
Throwable