graphics/java/android/graphics/RegionIterator.java

/*
 * Copyright (C) 2006 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 RegionIterator {

    /**
     * Construct an iterator for all of the rectangles in a region. This
     * effectively makes a private copy of the region, so any subsequent edits
     * to region will not affect the iterator.
     *
     * @param region the region that will be iterated
     */
    public RegionIterator(Region region) {
        mNativeIter = nativeConstructor(region.ni());
    }

    /**
     * Return the next rectangle in the region. If there are no more rectangles
     * this returns false and r is unchanged. If there is at least one more,
     * this returns true and r is set to that rectangle.
     */
    public final boolean next(Rect r) {
        if (r == null) {
            throw new NullPointerException("The Rect must be provided");
        }
        return nativeNext(mNativeIter, r);
    }
    
    protected void finalize() throws Throwable {
        nativeDestructor(mNativeIter);
        mNativeIter = 0;  // Other finalizers can still call us.
    }
    
    private static native long nativeConstructor(long native_region);
    private static native void nativeDestructor(long native_iter);
    private static native boolean nativeNext(long native_iter, Rect r);

    private long mNativeIter;
}