/*

 * Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * This file implements some of the standard utility procedures used

 * by the image conversion package.

 */

#include "img_globals.h"

#include "java_awt_image_IndexColorModel.h"

#include "java_awt_Transparency.h"

/*

 * This function constructs an 8x8 ordered dither array which can be

 * used to dither data into an output range with discreet values that

 * differ by the value specified as quantum.  A monochrome screen would

 * use a dither array constructed with the quantum 256.

 * The array values produced are unsigned and intended to be used with

 * a lookup table which returns the next color darker than the error

 * adjusted color used as the index.

 */

void

make_uns_ordered_dither_array(uns_ordered_dither_array oda,

                              int quantum)

{

    int i, j, k;

    oda[0][0] = 0;

    for (k = 1; k < 8; k *= 2) {

        for (i = 0; i < k; i++) {

            for (j = 0; j < k; j++) {

                oda[ i ][ j ] = oda[i][j] * 4;

                oda[i+k][j+k] = oda[i][j] + 1;

                oda[ i ][j+k] = oda[i][j] + 2;

                oda[i+k][ j ] = oda[i][j] + 3;

            }

        }

    }

    for (i = 0; i < 8; i++) {

        for (j = 0; j < 8; j++) {

            oda[i][j] = oda[i][j] * quantum / 64;

        }

    }

}

/*

 * This function constructs an 8x8 ordered dither array which can be

 * used to dither data into an output range with discreet values that

 * are distributed over the range from minerr to maxerr around a given

 * target color value.

 * The array values produced are signed and intended to be used with

 * a lookup table which returns the closest color to the error adjusted

 * color used as an index.

 */

void

make_sgn_ordered_dither_array(char* oda, int minerr, int maxerr)

{

    int i, j, k;

    oda[0] = 0;

    for (k = 1; k < 8; k *= 2) {

        for (i = 0; i < k; i++) {

            for (j = 0; j < k; j++) {

                oda[(i<<3) + j] = oda[(i<<3)+j] * 4;

                oda[((i+k)<<3) + j+k] = oda[(i<<3)+j] + 1;

                oda[(i<<3) + j+k] = oda[(i<<3)+j] + 2;

                oda[((i+k)<<3) + j] = oda[(i<<3)+j] + 3;

            }

        }

    }

    k = 0;

    for (i = 0; i < 8; i++) {

        for (j = 0; j < 8; j++) {

            oda[k] = oda[k] * (maxerr - minerr) / 64 + minerr;

            k++;

        }

    }

}

#ifdef TESTING

#include <stdio.h>

/* Function to test the ordered dither error matrix initialization function. */

main(int argc, char **argv)

{

    int i, j;

    int quantum;

    int max, val;

    uns_ordered_dither_array oda;

    if (argc > 1) {

        quantum = atoi(argv[1]);

    } else {

        quantum = 64;

    }

    make_uns_ordered_dither_array(oda, quantum);

    for (i = 0; i < 8; i++) {

        for (j = 0; j < 8; j++) {

            val = oda[i][j];

            printf("%4d", val);

            if (max < val) {

                max = val;

            }

        }

        printf("\n");

    }

    printf("\nmax = %d\n", max);

}

#endif /* TESTING */