/*
* Copyright (C) 2014 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.hardware.camera2.params;
import static com.android.internal.util.Preconditions.*;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.utils.HashCodeHelpers;
import android.util.Rational;
import java.util.Arrays;
/**
* Immutable class for describing a 3x3 matrix of {@link Rational} values in row-major order.
*
* <p>This matrix maps a transform from one color space to another. For the particular color space
* source and target, see the appropriate camera metadata documentation for the key that provides
* this value.</p>
*
* @see CameraMetadata
*/
public final class ColorSpaceTransform {
/** The number of rows in this matrix. */
private static final int ROWS = 3;
/** The number of columns in this matrix. */
private static final int COLUMNS = 3;
/** The number of total Rational elements in this matrix. */
private static final int COUNT = ROWS * COLUMNS;
/** Number of int elements in a rational. */
private static final int RATIONAL_SIZE = 2;
/** Numerator offset inside a rational (pair). */
private static final int OFFSET_NUMERATOR = 0;
/** Denominator offset inside a rational (pair). */
private static final int OFFSET_DENOMINATOR = 1;
/** Number of int elements in this matrix. */
private static final int COUNT_INT = ROWS * COLUMNS * RATIONAL_SIZE;
/**
* Create a new immutable {@link ColorSpaceTransform} instance from a {@link Rational} array.
*
* <p>The elements must be stored in a row-major order.</p>
*
* @param elements An array of {@code 9} elements
*
* @throws IllegalArgumentException
* if the count of {@code elements} is not {@code 9}
* @throws NullPointerException
* if {@code elements} or any sub-element is {@code null}
*/
public ColorSpaceTransform(Rational[] elements) {
checkNotNull(elements, "elements must not be null");
if (elements.length != COUNT) {
throw new IllegalArgumentException("elements must be " + COUNT + " length");
}
mElements = new int[COUNT_INT];
for (int i = 0; i < elements.length; ++i) {
checkNotNull(elements, "element[" + i + "] must not be null");
mElements[i * RATIONAL_SIZE + OFFSET_NUMERATOR] = elements[i].getNumerator();
mElements[i * RATIONAL_SIZE + OFFSET_DENOMINATOR] = elements[i].getDenominator();
}
}
/**
* Create a new immutable {@link ColorSpaceTransform} instance from an {@code int} array.
*
* <p>The elements must be stored in a row-major order. Each rational is stored
* contiguously as a {@code (numerator, denominator)} pair.</p>
*
* <p>In particular:<pre>{@code
* int[] elements = new int[
* N11, D11, N12, D12, N13, D13,
* N21, D21, N22, D22, N23, D23,
* N31, D31, N32, D32, N33, D33
* ];
*
* new ColorSpaceTransform(elements)}</pre>
*
* where {@code Nij} and {@code Dij} is the numerator and denominator for row {@code i} and
* column {@code j}.</p>
*
* @param elements An array of {@code 18} elements
*
* @throws IllegalArgumentException
* if the count of {@code elements} is not {@code 18}
* @throws NullPointerException
* if {@code elements} is {@code null}
*/
public ColorSpaceTransform(int[] elements) {
checkNotNull(elements, "elements must not be null");
if (elements.length != COUNT_INT) {
throw new IllegalArgumentException("elements must be " + COUNT_INT + " length");
}
for (int i = 0; i < elements.length; ++i) {
checkNotNull(elements, "element " + i + " must not be null");
}
mElements = Arrays.copyOf(elements, elements.length);
}
/**
* Get an element of this matrix by its row and column.
*
* <p>The rows must be within the range [0, 3),
* and the column must be within the range [0, 3).</p>
*
* @return element (non-{@code null})
*
* @throws IllegalArgumentException if column or row was out of range
*/
public Rational getElement(int column, int row) {
if (column < 0 || column >= COLUMNS) {
throw new IllegalArgumentException("column out of range");
} else if (row < 0 || row >= ROWS) {
throw new IllegalArgumentException("row out of range");
}
int numerator = mElements[(row * COLUMNS + column) * RATIONAL_SIZE + OFFSET_NUMERATOR];
int denominator = mElements[(row * COLUMNS + column) * RATIONAL_SIZE + OFFSET_DENOMINATOR];
return new Rational(numerator, denominator);
}
/**
* Copy the {@link Rational} elements in row-major order from this matrix into the destination.
*
* @param destination
* an array big enough to hold at least {@code 9} elements after the
* {@code offset}
* @param offset
* a non-negative offset into the array
* @throws NullPointerException
* If {@code destination} was {@code null}
* @throws ArrayIndexOutOfBoundsException
* If there's not enough room to write the elements at the specified destination and
* offset.
*/
public void copyElements(Rational[] destination, int offset) {
checkArgumentNonnegative(offset, "offset must not be negative");
checkNotNull(destination, "destination must not be null");
if (destination.length - offset < COUNT) {
throw new ArrayIndexOutOfBoundsException("destination too small to fit elements");
}
for (int i = 0, j = 0; i < COUNT; ++i, j += RATIONAL_SIZE) {
int numerator = mElements[j + OFFSET_NUMERATOR];
int denominator = mElements[j + OFFSET_DENOMINATOR];
destination[i + offset] = new Rational(numerator, denominator);
}
}
/**
* Copy the {@link Rational} elements in row-major order from this matrix into the destination.
*
* <p>Each element is stored as a contiguous rational packed as a
* {@code (numerator, denominator)} pair of ints, identical to the
* {@link ColorSpaceTransform#ColorSpaceTransform(int[]) constructor}.</p>
*
* @param destination
* an array big enough to hold at least {@code 18} elements after the
* {@code offset}
* @param offset
* a non-negative offset into the array
* @throws NullPointerException
* If {@code destination} was {@code null}
* @throws ArrayIndexOutOfBoundsException
* If there's not enough room to write the elements at the specified destination and
* offset.
*
* @see ColorSpaceTransform#ColorSpaceTransform(int[])
*/
public void copyElements(int[] destination, int offset) {
checkArgumentNonnegative(offset, "offset must not be negative");
checkNotNull(destination, "destination must not be null");
if (destination.length - offset < COUNT_INT) {
throw new ArrayIndexOutOfBoundsException("destination too small to fit elements");
}
// Manual copy faster than System#arraycopy for very small loops
for (int i = 0; i < COUNT_INT; ++i) {
destination[i + offset] = mElements[i];
}
}
/**
* Check if this {@link ColorSpaceTransform} is equal to another {@link ColorSpaceTransform}.
*
* <p>Two color space transforms are equal if and only if all of their elements are
* {@link Object#equals equal}.</p>
*
* @return {@code true} if the objects were equal, {@code false} otherwise
*/
@Override
public boolean equals(final Object obj) {
if (obj == null) {
return false;
}
if (this == obj) {
return true;
}
if (obj instanceof ColorSpaceTransform) {
final ColorSpaceTransform other = (ColorSpaceTransform) obj;
for (int i = 0, j = 0; i < COUNT; ++i, j += RATIONAL_SIZE) {
int numerator = mElements[j + OFFSET_NUMERATOR];
int denominator = mElements[j + OFFSET_DENOMINATOR];
int numeratorOther = other.mElements[j + OFFSET_NUMERATOR];
int denominatorOther = other.mElements[j + OFFSET_DENOMINATOR];
Rational r = new Rational(numerator, denominator);
Rational rOther = new Rational(numeratorOther, denominatorOther);
if (!r.equals(rOther)) {
return false;
}
}
return true;
}
return false;
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
return HashCodeHelpers.hashCode(mElements);
}
/**
* Return the color space transform as a string representation.
*
* <p> Example:
* {@code "ColorSpaceTransform([1/1, 0/1, 0/1], [0/1, 1/1, 0/1], [0/1, 0/1, 1/1])"} is an
* identity transform. Elements are printed in row major order. </p>
*
* @return string representation of color space transform
*/
@Override
public String toString() {
return String.format("ColorSpaceTransform%s", toShortString());
}
/**
* Return the color space transform as a compact string representation.
*
* <p> Example:
* {@code "([1/1, 0/1, 0/1], [0/1, 1/1, 0/1], [0/1, 0/1, 1/1])"} is an identity transform.
* Elements are printed in row major order. </p>
*
* @return compact string representation of color space transform
*/
private String toShortString() {
StringBuilder sb = new StringBuilder("(");
for (int row = 0, i = 0; row < ROWS; row++) {
sb.append("[");
for (int col = 0; col < COLUMNS; col++, i += RATIONAL_SIZE) {
int numerator = mElements[i + OFFSET_NUMERATOR];
int denominator = mElements[i + OFFSET_DENOMINATOR];
sb.append(numerator);
sb.append("/");
sb.append(denominator);
if (col < COLUMNS - 1) {
sb.append(", ");
}
}
sb.append("]");
if (row < ROWS - 1) {
sb.append(", ");
}
}
sb.append(")");
return sb.toString();
}
private final int[] mElements;
}
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