raster/color_write.c

Go to the documentation of this file.

/*!
 * \file lib/raster/color_write.c
 *
 * \brief Raster Library - Write color table of raster map
 *
 * SPDX-FileCopyrightText: 1999-2009 GRASS Development Team
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * \author USACERL and many others
 */
 
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <grass/gis.h>
#include <grass/glocale.h>
#include <grass/raster.h>
 
static void write_rules(FILE *, struct _Color_Rule_ *, DCELL, DCELL);
static void write_new_colors(FILE *, struct Colors *);
static void write_old_colors(FILE *, struct Colors *);
static void forced_write_old_colors(FILE *, struct Colors *);
static void format_min(char *, double);
static void format_max(char *, double);
 
#define FORMAT_STR_SZ 100
 
/*!
 * \brief Write map layer color table
 *
 * The color table is written for the raster map <i>name</i> in the
 * specified <i>mapset</i> from the <i>colors</i> structure.
 *
 * If there is an error, -1 is returned. No diagnostic is
 * printed. Otherwise, 1 is returned.
 *
 * The <i>colors</i> structure must be created properly, i.e.,
 * Rast_init_colors() to initialize the structure and Rast_add_c_color_rule()
 * to set the category colors. These routines are called by
 * higher level routines which read or create entire color tables,
 * such as Rast_read_colors() or Rast_make_ramp_colors().
 *
 * <b>Note:</b> The calling sequence for this function deserves
 * special attention. The <i>mapset</i> parameter seems to imply that
 * it is possible to overwrite the color table for a raster map which
 * is in another mapset. However, this is not what actually
 * happens. It is very useful for users to create their own color
 * tables for raster maps in other mapsets, but without overwriting
 * other users' color tables for the same raster map. If <i>mapset</i>
 * is the current mapset, then the color file for <i>name</i> will be
 * overwritten by the new color table. But if <i>mapset</i> is not the
 * current mapset, then the color table is actually written in the
 * current mapset under the <tt>colr2</tt> element as:
 * <tt>colr2/mapset/name</tt>.
 *
 * The rules are written out using floating-point format, removing
 * trailing zeros (possibly producing integers).  The flag marking the
 * colors as floating-point is <b>not</b> written.
 *
 * If the environment variable FORCE_GRASS3_COLORS is set (to anything at all)
 * then the output format is 3.0, even if the structure contains 4.0 rules.
 * This allows users to create 3.0 color files for export to sites which
 * don't yet have 4.0
 *
 * \param name map name
 * \param mapset mapset name
 * \param colors pointer to structure Colors which holds color info
 *
 * \return void
 */
void Rast_write_colors(const char *name, const char *mapset,
                       struct Colors *colors)
{
    char element[512];
    char xname[GNAME_MAX], xmapset[GMAPSET_MAX];
    FILE *fd;
 
    if (G_name_is_fully_qualified(name, xname, xmapset)) {
        if (strcmp(xmapset, mapset) != 0)
            G_fatal_error(_("Qualified name <%s> doesn't match mapset <%s>"),
                          name, mapset);
        name = xname;
    }
    /*
     * if mapset is current mapset, remove colr2 file (created by pre 3.0 grass)
     *    and then write original color table
     * else write secondary color table
     */
    snprintf(element, sizeof(element), "colr2/%s", mapset);
    if (strcmp(mapset, G_mapset()) == 0) {
        G_remove(element, name); /* get rid of existing colr2, if any */
        strcpy(element, "colr");
    }
    if (!(fd = G_fopen_new(element, name)))
        G_fatal_error(_("Unable to create <%s> file for map <%s>"), element,
                      name);
 
    Rast__write_colors(fd, colors);
    fclose(fd);
}
 
/*!
 * \brief Write map layer color table
 *
 * \param fd file descriptor
 * \param colors pointer to Colors structure which holds color info
 */
void Rast__write_colors(FILE *fd, struct Colors *colors)
{
    if (getenv("FORCE_GRASS3_COLORS"))
        forced_write_old_colors(fd, colors);
    else if (colors->version < 0)
        write_old_colors(fd, colors);
    else
        write_new_colors(fd, colors);
}
 
static void write_new_colors(FILE *fd, struct Colors *colors)
{
    char str1[100], str2[100];
 
    format_min(str1, (double)colors->cmin);
    format_max(str2, (double)colors->cmax);
    fprintf(fd, "%% %s %s\n", str1, str2);
 
    if (colors->shift) {
        snprintf(str2, sizeof(str2), "%.17g", (double)colors->shift);
        G_trim_decimal(str2);
        fprintf(fd, "shift:%s\n", str2);
    }
    if (colors->invert)
        fprintf(fd, "invert\n");
 
    if (colors->null_set) {
        fprintf(fd, "nv:%d", colors->null_red);
        if (colors->null_red != colors->null_grn ||
            colors->null_red != colors->null_blu)
            fprintf(fd, ":%d:%d", colors->null_grn, colors->null_blu);
        fprintf(fd, "\n");
    }
    if (colors->undef_set) {
        fprintf(fd, "*:%d", colors->undef_red);
        if (colors->undef_red != colors->undef_grn ||
            colors->undef_red != colors->undef_blu)
            fprintf(fd, ":%d:%d", colors->undef_grn, colors->undef_blu);
        fprintf(fd, "\n");
    }
    if (colors->modular.rules) {
        fprintf(fd, "%s\n", "%%");
        write_rules(fd, colors->modular.rules, colors->cmin, colors->cmax);
        fprintf(fd, "%s\n", "%%");
    }
    if (colors->fixed.rules)
        write_rules(fd, colors->fixed.rules, colors->cmin, colors->cmax);
}
 
/* overall min and max data values in color table */
static void write_rules(FILE *fd, struct _Color_Rule_ *crules, DCELL dmin,
                        DCELL dmax)
{
    struct _Color_Rule_ *rule;
    char str[FORMAT_STR_SZ];
 
    /* find the end of the rules list */
    rule = crules;
    while (rule->next)
        rule = rule->next;
 
    /* write out the rules in reverse order */
    for (; rule; rule = rule->prev) {
        if (rule->low.value == dmin)
            format_min(str, (double)rule->low.value);
        else {
            snprintf(str, FORMAT_STR_SZ, "%.17g", (double)rule->low.value);
            G_trim_decimal(str);
        }
        fprintf(fd, "%s:%d", str, (int)rule->low.red);
        if (rule->low.red != rule->low.grn || rule->low.red != rule->low.blu)
            fprintf(fd, ":%d:%d", rule->low.grn, rule->low.blu);
        /* even if low==high, write second end when the high is dmax */
        if (rule->high.value == dmax || rule->low.value != rule->high.value) {
            if (rule->high.value == dmax)
                format_max(str, (double)rule->high.value);
            else {
                snprintf(str, FORMAT_STR_SZ, "%.17g", (double)rule->high.value);
                G_trim_decimal(str);
            }
            fprintf(fd, " %s:%d", str, (int)rule->high.red);
            if (rule->high.red != rule->high.grn ||
                rule->high.red != rule->high.blu)
                fprintf(fd, ":%d:%d", rule->high.grn, rule->high.blu);
        }
        fprintf(fd, "\n");
    }
}
 
static void write_old_colors(FILE *fd, struct Colors *colors)
{
    int i, n;
 
    fprintf(fd, "#%ld first color\n", (long)colors->fixed.min);
    if (colors->null_set) {
        fprintf(fd, "%d %d %d\n", (int)colors->null_red, (int)colors->null_grn,
                (int)colors->null_blu);
    }
    else
        fprintf(fd, "255 255 255\n"); /* white */
 
    n = colors->fixed.max - colors->fixed.min + 1;
 
    for (i = 0; i < n; i++) {
        fprintf(fd, "%d", (int)colors->fixed.lookup.red[i]);
        if (colors->fixed.lookup.red[i] != colors->fixed.lookup.grn[i] ||
            colors->fixed.lookup.red[i] != colors->fixed.lookup.blu[i])
            fprintf(fd, " %d %d", (int)colors->fixed.lookup.grn[i],
                    (int)colors->fixed.lookup.blu[i]);
        fprintf(fd, "\n");
    }
}
 
static void forced_write_old_colors(FILE *fd, struct Colors *colors)
{
    int red, grn, blu;
    CELL cat;
 
    fprintf(fd, "#%ld first color\n", (long)colors->cmin);
    cat = 0;
    Rast_get_c_color(&cat, &red, &grn, &blu, colors);
    fprintf(fd, "%d %d %d\n", red, grn, blu);
 
    for (cat = colors->cmin; cat <= colors->cmax; cat++) {
        Rast_get_c_color(&cat, &red, &grn, &blu, colors);
        fprintf(fd, "%d", red);
        if (red != grn || red != blu)
            fprintf(fd, " %d %d", grn, blu);
        fprintf(fd, "\n");
    }
}
 
static void format_min(char *str, double dval)
{
    double dtmp;
 
    snprintf(str, FORMAT_STR_SZ, "%.17g", dval);
    /* Note that G_trim_decimal() does not trim e.g. 1.0000000e-20 */
    G_trim_decimal(str);
    sscanf(str, "%lf", &dtmp);
    if (dtmp != dval) { /* if no zeros after decimal point were trimmed */
        /* lower dval by GRASS_EPSILON fraction */
        if (dval > 0)
            snprintf(str, FORMAT_STR_SZ, "%.17g", dval * (1 - GRASS_EPSILON));
        else
            snprintf(str, FORMAT_STR_SZ, "%.17g", dval * (1 + GRASS_EPSILON));
    }
}
 
static void format_max(char *str, double dval)
{
    double dtmp;
 
    snprintf(str, FORMAT_STR_SZ, "%.17g", dval);
    /* Note that G_trim_decimal() does not trim e.g. 1.0000000e-20 */
    G_trim_decimal(str);
    sscanf(str, "%lf", &dtmp);
    if (dtmp != dval) { /* if  no zeros after decimal point were trimmed */
        /* increase dval by by GRASS_EPSILON fraction */
        if (dval > 0)
            snprintf(str, FORMAT_STR_SZ, "%.17g", dval * (1 + GRASS_EPSILON));
        else
            snprintf(str, FORMAT_STR_SZ, "%.17g", dval * (1 - GRASS_EPSILON));
    }
}