Get the average color of a rect area of a YUV420SPNV21 byte array - Android Graphics

Android examples for Graphics:Color RGB Value

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Description

Get the average color of a rect area of a YUV420SPNV21 byte array

Demo Code

/*//from  ww w. j  a  va2s  . c o  m
 * Copyright 2014 Martin Brabham
 * Copyright 2014 Daniel Velazco
 * 
 * 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.
 */
import android.graphics.Color;

public class Main{
    public static int FRAME_WIDTH = 640;
    public static int FRAME_HEIGHT = 480;
    /**
     * Get the average color of a rect area of a YUV420SPNV21 byte array
     *
     * @param yuv byte array
     * @param x1  {@link Integer}
     * @param y1  {@link Integer}
     * @param x2  {@link Integer}
     * @param y2  {@link Integer}
     * @return {@link com.holoyolostudios.colorvision.colorlib.util.ColorAnalyzerUtil.RGBColor}
     */
    public static RGBColor getAverageColor(byte[] yuv, int x1, int y1,
            int x2, int y2) {

        // Set variables
        int i = 0;
        int j = 0;
        int k = 0;
        int m = 0;

        // Gather pixel data for the square
        for (int i1 = x1; i1 <= x2; i1++) {
            for (int i2 = y1; i2 < y2; i2++) {
                int color = getColorAtPoint(yuv, i1, i2);
                j += Color.red(color);
                k += Color.green(color);
                m += Color.blue(color);
                i++;
            }
        }

        // Average data
        j = j / i;
        k = k / i;
        m = m / i;

        // Normalize data
        j = (j > 255) ? 255 : j;
        j = (j < 0) ? 0 : j;
        k = (k > 255) ? 255 : k;
        k = (k < 0) ? 0 : k;
        m = (m > 255) ? 255 : m;
        m = (m < 0) ? 0 : m;

        return new RGBColor(j, k, m);
    }
    /**
     * Gets the RGB pixel at the given position in a YUV420SPNV21 byte array
     *
     * @param yuv byte array
     * @param x   {@link Integer}
     * @param y   {@link Integer}
     * @return {@link Integer}
     */
    public static int getColorAtPoint(byte[] yuv, int x, int y) {
        int i = (FRAME_WIDTH * FRAME_HEIGHT) + FRAME_WIDTH * (y >> 1)
                + (x & 0xFFFFFFFE);
        int j = 0xFF & yuv[x + y * FRAME_WIDTH];
        int k = 0xFF & yuv[(i + 1)];
        int m = 0xFF & yuv[i];
        int n = k - 128;
        int i1 = m - 128;
        int i2 = (int) (j + 1.402f * i1);
        int i3 = (int) (j - 0.344f * n - 0.714f * i1);
        int i4 = (int) (j + 1.772f * n);
        i2 = (i2 < 0) ? 0 : i2;
        i2 = (i2 > 255) ? 255 : i2;
        i3 = (i3 < 0) ? 0 : i3;
        i3 = (i3 > 255) ? 255 : i3;
        i4 = (i4 < 0) ? 0 : i4;
        i4 = (i4 > 255) ? 255 : i4;
        return Color.rgb(i2, i3, i4);
    }
}

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