RectUtils.java revision 93a35b93dc582e38ff8ee5979754a16b4bf4da0c 
1/*
2 * Copyright (C) 2013 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 com.android.bitmap.util;
18
19import android.graphics.Matrix;
20import android.graphics.Rect;
21import android.graphics.RectF;
22
23public class RectUtils {
24
25    /**
26     * Transform the upright full rectangle so that it bounds the original rotated image,
27     * given by the orientation. Transform the upright partial rectangle such that it would apply
28     * to the same region of the transformed full rectangle.
29     *
30     * The top-left of the transformed full rectangle will always be placed at (0, 0).
31     * @param orientation The exif orientation (0, 90, 180, 270) of the original image. The
32     *                    transformed full and partial rectangles will be in this orientation's
33     *                    coordinate space.
34     * @param fullRect    The upright full rectangle. This rectangle will be modified.
35     * @param partialRect The upright partial rectangle. This rectangle will be modified.
36     */
37    public static void rotateRectForOrientation(final int orientation, final Rect fullRect,
38            final Rect partialRect) {
39        final Matrix matrix = new Matrix();
40        // Exif orientation specifies how the camera is rotated relative to the actual subject.
41        // First rotate in the opposite direction.
42        matrix.setRotate(-orientation);
43        final RectF fullRectF = new RectF(fullRect);
44        final RectF partialRectF = new RectF(partialRect);
45        matrix.mapRect(fullRectF);
46        matrix.mapRect(partialRectF);
47        // Then translate so that the upper left corner of the rotated full rect is at (0,0).
48        matrix.reset();
49        matrix.setTranslate(-fullRectF.left, -fullRectF.top);
50        matrix.mapRect(fullRectF);
51        matrix.mapRect(partialRectF);
52        // Orientation transformation is complete.
53        fullRect.set((int) fullRectF.left, (int) fullRectF.top, (int) fullRectF.right,
54                (int) fullRectF.bottom);
55        partialRect.set((int) partialRectF.left, (int) partialRectF.top, (int) partialRectF.right,
56                (int) partialRectF.bottom);
57    }
58
59    public static void rotateRect(final int degrees, final int px, final int py, final Rect rect) {
60        final RectF rectF = new RectF(rect);
61        final Matrix matrix = new Matrix();
62        matrix.setRotate(degrees, px, py);
63        matrix.mapRect(rectF);
64        rect.set((int) rectF.left, (int) rectF.top, (int) rectF.right, (int) rectF.bottom);
65    }
66}
67