src.android.graphics.PathMeasure Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of android-all Show documentation
Show all versions of android-all Show documentation
A library jar that provides APIs for Applications written for the Google Android Platform.
/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.graphics;
public class PathMeasure {
private Path mPath;
/**
* 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() {
mPath = null;
native_instance = native_create(0, false);
}
/**
* 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.
*
* @param path The path that will be measured by this object
* @param forceClosed If true, then the path will be considered as "closed"
* even if its contour was not explicitly closed.
*/
public PathMeasure(Path path, boolean forceClosed) {
// The native implementation does not copy the path, prevent it from being GC'd
mPath = path;
native_instance = native_create(path != null ? path.readOnlyNI() : 0,
forceClosed);
}
/**
* Assign a new path, or null to have none.
*/
public void setPath(Path path, boolean forceClosed) {
mPath = path;
native_setPath(native_instance,
path != null ? path.readOnlyNI() : 0,
forceClosed);
}
/**
* Return the total length of the current contour, or 0 if no path is
* associated with this measure object.
*/
public float getLength() {
return native_getLength(native_instance);
}
/**
* 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.
*
* @param distance The distance along the current contour to sample
* @param pos If not null, returns the sampled position (x==[0], y==[1])
* @param tan If not null, returns the sampled tangent (x==[0], y==[1])
* @return false if there was no path associated with this measure object
*/
public boolean getPosTan(float distance, float pos[], float tan[]) {
if (pos != null && pos.length < 2 ||
tan != null && tan.length < 2) {
throw new ArrayIndexOutOfBoundsException();
}
return native_getPosTan(native_instance, distance, pos, tan);
}
public static final int POSITION_MATRIX_FLAG = 0x01; // must match flags in SkPathMeasure.h
public static final int TANGENT_MATRIX_FLAG = 0x02; // must match flags in SkPathMeasure.h
/**
* 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.
*
* @param distance The distance along the associated path
* @param matrix Allocated by the caller, this is set to the transformation
* associated with the position and tangent at the specified distance
* @param flags Specified what aspects should be returned in the matrix.
*/
public boolean getMatrix(float distance, Matrix matrix, int flags) {
return native_getMatrix(native_instance, distance, matrix.ni(), flags);
}
/**
* 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 {@link android.os.Build.VERSION_CODES#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).
*/
public boolean getSegment(float startD, float stopD, Path dst, boolean startWithMoveTo) {
// Skia used to enforce this as part of it's API, but has since relaxed that restriction
// so to maintain consistency in our API we enforce the preconditions here.
float length = getLength();
if (startD < 0) {
startD = 0;
}
if (stopD > length) {
stopD = length;
}
if (startD >= stopD) {
return false;
}
return native_getSegment(native_instance, startD, stopD, dst.mutateNI(), startWithMoveTo);
}
/**
* Return true if the current contour is closed()
*/
public boolean isClosed() {
return native_isClosed(native_instance);
}
/**
* Move to the next contour in the path. Return true if one exists, or
* false if we're done with the path.
*/
public boolean nextContour() {
return native_nextContour(native_instance);
}
protected void finalize() throws Throwable {
native_destroy(native_instance);
native_instance = 0; // Other finalizers can still call us.
}
private static native long native_create(long native_path, boolean forceClosed);
private static native void native_setPath(long native_instance, long native_path, boolean forceClosed);
private static native float native_getLength(long native_instance);
private static native boolean native_getPosTan(long native_instance, float distance, float pos[], float tan[]);
private static native boolean native_getMatrix(long native_instance, float distance, long native_matrix, int flags);
private static native boolean native_getSegment(long native_instance, float startD, float stopD, long native_path, boolean startWithMoveTo);
private static native boolean native_isClosed(long native_instance);
private static native boolean native_nextContour(long native_instance);
private static native void native_destroy(long native_instance);
/* package */private long native_instance;
}