color_rule_get.c

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/*!
 * \file lib/raster/color_rule_get.c
 *
 * \brief Raster Library - Get color rules.
 *
 * (C) 2001-2009 by the GRASS Development Team
 *
 * This program is free software under the GNU General Public License
 * (>=v2). Read the file COPYING that comes with GRASS for details.
 *
 * \author Original author CERL
 */
 
#include <grass/gis.h>
#include <grass/raster.h>
 
/*!
   \brief Get both modular and fixed rules count
 
   \param colors pointer to color table structure
 
   \return number of rules in color table
 */
int Rast_colors_count(const struct Colors *colors)
{
    int count = 0;
    struct _Color_Rule_ *rule;
 
    if (colors->fixed.rules) {
        count++;
        rule = colors->fixed.rules;
 
        while (rule->next) {
            count++;
            rule = rule->next;
        }
    }
    if (colors->modular.rules) {
        count++;
        rule = colors->modular.rules;
 
        while (rule->next) {
            count++;
            rule = rule->next;
        }
    }
    return count;
}
 
/*!
   \brief Get color rule from both modular and fixed rules
 
   Rules are returned in the order as stored in the table
   (i.e. unexpected, high values first)
 
   \param val1 color value
   \param[out] r1,g1,b1 color value
   \param val2 color value
   \param[out] r2,g2,b2 color value
   \param colors pointer to color table structure
   \param rule rule index from 0 to G_color_count()-1
 
   \return 0 success
   \return 1 index out of range
 */
int Rast_get_fp_color_rule(DCELL *val1, unsigned char *r1, unsigned char *g1,
                           unsigned char *b1, DCELL *val2, unsigned char *r2,
                           unsigned char *g2, unsigned char *b2,
                           const struct Colors *colors, int rule)
{
    int index = -1;
    int found = 0;
    const struct _Color_Rule_ *rl;
 
    *val1 = *val2 = 0.0;
    *r1 = *g1 = *b1 = *r2 = *g2 = *b2 = 0;
 
    /* Find the rule */
    if (colors->fixed.rules) {
        rl = colors->fixed.rules;
        index++;
        if (index == rule)
            found = 1;
 
        while (!found && rl->next) {
            rl = rl->next;
            index++;
            if (index == rule)
                found = 1;
        }
    }
    if (!found && colors->modular.rules) {
        rl = colors->modular.rules;
        index++;
        if (index == rule)
            found = 1;
 
        while (!found && rl->next) {
            rl = rl->next;
            index++;
            if (index == rule)
                found = 1;
        }
    }
 
    if (!found)
        return 1;
 
    /* Set values */
    *val1 = rl->low.value;
    *val2 = rl->high.value;
 
    *r1 = rl->low.red;
    *g1 = rl->low.grn;
    *b1 = rl->low.blu;
 
    *r2 = rl->high.red;
    *g2 = rl->high.grn;
    *b2 = rl->high.blu;
 
    return 0;
}