1 /*
2  * Copyright (C) 2014 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 android.hardware.camera2.params;
18 
19 import java.util.Arrays;
20 
21 import static com.android.internal.util.Preconditions.checkNotNull;
22 
23 /**
24  * Immutable class to store a 4-element vector of integers corresponding to a 2x2 pattern
25  * of color channel offsets used for the black level offsets of each color channel.
26  */
27 public final class BlackLevelPattern {
28 
29     /**
30      * The number of offsets in this vector.
31      */
32     public static final int COUNT = 4;
33 
34     /**
35      * Create a new {@link BlackLevelPattern} from a given offset array.
36      *
37      * <p>The given offset array must contain offsets for each color channel in
38      * a 2x2 pattern corresponding to the color filter arrangement.  Offsets are
39      * given in row-column scan order.</p>
40      *
41      * @param offsets an array containing a 2x2 pattern of offsets.
42      *
43      * @throws IllegalArgumentException if the given array has an incorrect length.
44      * @throws NullPointerException if the given array is null.
45      * @hide
46      */
BlackLevelPattern(int[] offsets)47     public BlackLevelPattern(int[] offsets) {
48         if (offsets == null) {
49             throw new NullPointerException("Null offsets array passed to constructor");
50         }
51         if (offsets.length < COUNT) {
52             throw new IllegalArgumentException("Invalid offsets array length");
53         }
54         mCfaOffsets = Arrays.copyOf(offsets, COUNT);
55     }
56 
57     /**
58      * Return the color channel offset for a given index into the array of raw pixel values.
59      *
60      * @param column the column index in the the raw pixel array.
61      * @param row the row index in the raw pixel array.
62      * @return a color channel offset.
63      *
64      * @throws IllegalArgumentException if a column or row given is negative.
65      */
getOffsetForIndex(int column, int row)66     public int getOffsetForIndex(int column, int row) {
67         if (row < 0 || column < 0) {
68             throw new IllegalArgumentException("column, row arguments must be positive");
69         }
70         return mCfaOffsets[((row & 1) << 1) | (column & 1)];
71     }
72 
73     /**
74      * Copy the ColorChannel offsets into the destination vector.
75      *
76      * <p>Offsets are given in row-column scan order for a given 2x2 color pattern.</p>
77      *
78      * @param destination an array big enough to hold at least {@value #COUNT} elements after the
79      *          {@code offset}
80      * @param offset a non-negative offset into the array
81      *
82      * @throws IllegalArgumentException if the offset is invalid.
83      * @throws ArrayIndexOutOfBoundsException if the destination vector is too small.
84      * @throws NullPointerException if the destination is null.
85      */
copyTo(int[] destination, int offset)86     public void copyTo(int[] destination, int offset) {
87         checkNotNull(destination, "destination must not be null");
88         if (offset < 0) {
89             throw new IllegalArgumentException("Null offset passed to copyTo");
90         }
91         if (destination.length - offset < COUNT) {
92             throw new ArrayIndexOutOfBoundsException("destination too small to fit elements");
93         }
94         for (int i = 0; i < COUNT; ++i) {
95             destination[offset + i] = mCfaOffsets[i];
96         }
97     }
98 
99     /**
100      * Check if this {@link BlackLevelPattern} is equal to another {@link BlackLevelPattern}.
101      *
102      * <p>Two vectors are only equal if and only if each of the respective elements is equal.</p>
103      *
104      * @return {@code true} if the objects were equal, {@code false} otherwise
105      */
106     @Override
equals(Object obj)107     public boolean equals(Object obj) {
108         if (obj == null) {
109             return false;
110         } else if (this == obj) {
111             return true;
112         } else if (obj instanceof BlackLevelPattern) {
113             final BlackLevelPattern other = (BlackLevelPattern) obj;
114             return Arrays.equals(other.mCfaOffsets, mCfaOffsets);
115         }
116         return false;
117     }
118 
119     /**
120      * {@inheritDoc}
121      */
122     @Override
hashCode()123     public int hashCode() {
124         return Arrays.hashCode(mCfaOffsets);
125     }
126 
127     /**
128      * Return this {@link BlackLevelPattern} as a string representation.
129      *
130      * <p> {@code "BlackLevelPattern([%d, %d], [%d, %d])"}, where each {@code %d} represents one
131      * black level offset of a color channel. The values are in the same order as channels listed
132      * for the CFA layout key (see
133      * {@link android.hardware.camera2.CameraCharacteristics#SENSOR_INFO_COLOR_FILTER_ARRANGEMENT}).
134      * </p>
135      *
136      * @return string representation of {@link BlackLevelPattern}
137      *
138      * @see android.hardware.camera2.CameraCharacteristics#SENSOR_INFO_COLOR_FILTER_ARRANGEMENT
139      */
140     @Override
toString()141     public String toString() {
142         return String.format("BlackLevelPattern([%d, %d], [%d, %d])", mCfaOffsets[0],
143                 mCfaOffsets[1], mCfaOffsets[2], mCfaOffsets[3]);
144     }
145 
146     private final int[] mCfaOffsets;
147 }
148