png.c

/*
 * png.c
 * greg hewgill
 * august 2009
 *
 * Copyright (C) 1989, 1990, 1993-1995, 1999 Kirk Lauritz Johnson
 *
 * Parts of the source code (as marked) are:
 *   Copyright (C) 1989, 1990, 1991 by Jim Frost
 *   Copyright (C) 1992 by Jamie Zawinski <jwz@lucid.com>
 *
 * Permission to use, copy, modify and freely distribute xearth for
 * non-commercial and not-for-profit purposes is hereby granted
 * without fee, provided that both the above copyright notice and this
 * permission notice appear in all copies and in supporting
 * documentation.
 *
 * The author makes no representations about the suitability of this
 * software for any purpose. It is provided "as is" without express or
 * implied warranty.
 *
 * THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT
 * OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "xearth.h"

#include <gd.h>

static void png_setup _P ((void));
static int png_row _P ((u_char *));
static void png_cleanup _P ((FILE *));
static void png_truecolor_setup _P ((void));
static int png_truecolor_row _P ((u_char *));
static void png_truecolor_cleanup _P ((FILE *));

static u16or32 *dith;
static gdImagePtr img;
static int y;
static int colors[256];

void
png_output ()
{
    compute_positions ();
    scan_map ();
    do_dots ();
    if (num_colors > 256) {
        png_truecolor_setup ();
        render (png_truecolor_row);
        png_truecolor_cleanup (stdout);
    } else {
        png_setup ();
        render (png_row);
        png_cleanup (stdout);
    }
}

static void
png_setup ()
{
    int i;

    img = gdImageCreate (wdth, hght);

    dither_setup (num_colors);
    dith = (u16or32 *) malloc ((unsigned) sizeof (u16or32) * wdth);
    assert (dith != NULL);

    for (i = 0; i < dither_ncolors; i++) {
        colors[i] = gdImageColorAllocate (img,
                                          dither_colormap[i * 3 + 0],
                                          dither_colormap[i * 3 + 1],
                                          dither_colormap[i * 3 + 2]);
    }

    y = 0;
}

static int
png_row (row)
    u_char *row;
{
    int i, i_lim;
    u16or32 *tmp;

    tmp = dith;
    dither_row (row, tmp);

    /* use i_lim to encourage compilers to register loop limit
     */
    i_lim = wdth;
    for (i = 0; i < i_lim; i++)
        gdImageSetPixel (img, i, y, colors[tmp[i]]);

    y += 1;

    return 0;
}

static void
png_cleanup (s)
    FILE *s;
{
    gdImagePng (img, s);
    gdImageDestroy (img);

    dither_cleanup ();
    free (dith);
}

static void
png_truecolor_setup ()
{
    img = gdImageCreateTrueColor (wdth, hght);

    y = 0;
}

static int
png_truecolor_row (row)
    u_char *row;
{
    int i;

    for (i = 0; i < wdth; i++)
        gdImageSetPixel (img, i, y,
                         gdTrueColor (row[i * 3 + 0], row[i * 3 + 1],
                                      row[i * 3 + 2]));

    y += 1;

    return 0;
}

static void
png_truecolor_cleanup (s)
    FILE *s;
{
    gdImagePng (img, s);
    gdImageDestroy (img);
}