Create a histogram over the ARGB component distribution. - Java javax.microedition.lcdui

Java examples for javax.microedition.lcdui:Image

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Description

Create a histogram over the ARGB component distribution.

Demo Code

/*/*from  ww  w. ja  va  2  s.com*/
 * This file is a part of the TUBE42 imagelib, released under the LGPL license.
 *
 * Development page: https://github.com/tube42/imagelib
 * License:          http://www.gnu.org/copyleft/lesser.html
 */
import javax.microedition.lcdui.*;

public class Main{
    /**
     * Create a histogram over the ARGB component distribution.
     * 
     * Note that this function returns pixel counters, so
     * the accumulative total for each component is w * h, not 1.0
     */
    public static int[][] getARGBHistogram(Image image) {
        int w = image.getWidth();
        int h = image.getHeight();

        return getARGBHistogram(image, 0, 0, w, h);
    }
    /**
     * Create a histogram over the ARGB component distribution
     * of selected parts in an image.
     *      
     * Note that this function returns pixel counters, so
     * the accumulative total for each component is w * h, not 1.0
     */
    public static int[][] getARGBHistogram(Image image, int x, int y,
            int w, int h) {
        // 1. create initial empty histogram
        int[][] ret = new int[4][];
        for (int i = 0; i < ret.length; i++) {
            ret[i] = new int[256];
            for (int j = 0; j < 256; j++)
                ret[i][j] = 0;
        }

        // 2. build histogram
        int[] buffer = new int[w];
        for (int i = 0; i < h; i++) {
            image.getRGB(buffer, 0, w, 0, i, w, 1);

            for (int j = 0; j < w; j++) {
                int c = buffer[j];

                ret[0][(c >> 24) & 0xFF]++;
                ret[1][(c >> 16) & 0xFF]++;
                ret[2][(c >> 8) & 0xFF]++;
                ret[3][(c >> 0) & 0xFF]++;
            }
        }

        // 3. and we are done
        return ret;
    }
}

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