1/*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.graphics;
18
19import android.os.Parcel;
20import android.os.Parcelable;
21import android.util.DisplayMetrics;
22
23import java.io.OutputStream;
24import java.nio.Buffer;
25import java.nio.ByteBuffer;
26import java.nio.IntBuffer;
27import java.nio.ShortBuffer;
28
29/**
30 * LargeBitmap can be used to decode a rectangle region from an image.
31 * LargeBimap is particularly useful when an original image is large and
32 * you only need parts of the image.
33 *
34 * To create a LargeBitmap, call BitmapFactory.createLargeBitmap().
35 * Given a LargeBitmap, users can call decodeRegion() repeatedly
36 * to get a decoded Bitmap of the specified region.
37 * @hide
38 */
39public final class LargeBitmap {
40    private int mNativeLargeBitmap;
41    private boolean mRecycled;
42
43    /*  Private constructor that must received an already allocated native
44        large bitmap int (pointer).
45
46        This can be called from JNI code.
47    */
48    private LargeBitmap(int lbm) {
49        mNativeLargeBitmap = lbm;
50        mRecycled = false;
51    }
52
53    /**
54     * Decodes a rectangle region in the image specified by rect.
55     *
56     * @param rect The rectangle that specified the region to be decode.
57     * @param opts null-ok; Options that control downsampling.
58     *             inPurgeable is not supported.
59     * @return The decoded bitmap, or null if the image data could not be
60     *         decoded.
61     */
62    public Bitmap decodeRegion(Rect rect, BitmapFactory.Options options) {
63        checkRecycled("decodeRegion called on recycled large bitmap");
64        if (rect.left < 0 || rect.top < 0 || rect.right > getWidth() || rect.bottom > getHeight())
65            throw new IllegalArgumentException("rectangle is not inside the image");
66        return nativeDecodeRegion(mNativeLargeBitmap, rect.left, rect.top,
67                rect.right - rect.left, rect.bottom - rect.top, options);
68    }
69
70    /** Returns the original image's width */
71    public int getWidth() {
72        checkRecycled("getWidth called on recycled large bitmap");
73        return nativeGetWidth(mNativeLargeBitmap);
74    }
75
76    /** Returns the original image's height */
77    public int getHeight() {
78        checkRecycled("getHeight called on recycled large bitmap");
79        return nativeGetHeight(mNativeLargeBitmap);
80    }
81
82    /**
83     * Frees up the memory associated with this large bitmap, and mark the
84     * large bitmap as "dead", meaning it will throw an exception if decodeRegion(),
85     * getWidth() or getHeight() is called.
86     * This operation cannot be reversed, so it should only be called if you are
87     * sure there are no further uses for the large bitmap. This is an advanced call,
88     * and normally need not be called, since the normal GC process will free up this
89     * memory when there are no more references to this bitmap.
90     */
91    public void recycle() {
92        if (!mRecycled) {
93            nativeClean(mNativeLargeBitmap);
94            mRecycled = true;
95        }
96    }
97
98    /**
99     * Returns true if this large bitmap has been recycled.
100     * If so, then it is an error to try use its method.
101     *
102     * @return true if the large bitmap has been recycled
103     */
104    public final boolean isRecycled() {
105        return mRecycled;
106    }
107
108    /**
109     * Called by methods that want to throw an exception if the bitmap
110     * has already been recycled.
111     */
112    private void checkRecycled(String errorMessage) {
113        if (mRecycled) {
114            throw new IllegalStateException(errorMessage);
115        }
116    }
117
118    protected void finalize() {
119        recycle();
120    }
121
122    private static native Bitmap nativeDecodeRegion(int lbm,
123            int start_x, int start_y, int width, int height,
124            BitmapFactory.Options options);
125    private static native int nativeGetWidth(int lbm);
126    private static native int nativeGetHeight(int lbm);
127    private static native void nativeClean(int lbm);
128}
129