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 
17 package com.android.bitmap.util;
18 
19 import android.graphics.Matrix;
20 import android.graphics.Rect;
21 import android.graphics.RectF;
22 
23 public 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      */
rotateRectForOrientation(final int orientation, final Rect fullRect, final Rect partialRect)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 
rotateRect(final int degrees, final int px, final int py, final Rect rect)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