Geografic-Information-System/lib/gis/color_get.c

/**
 * \file color_get.c
 *
 * \brief GIS Library - Functions to get colors from a raster map.
 *
 * (C) 2001-2008 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 GRASS GIS Development Team
 *
 * \date 1999-2008
 */

#include <grass/gis.h>


/**
 * \brief Get a category color.
 *
 * The <b>red, green</b>, and
 * <b>blue</b> intensities for the color associated with category <b>n</b>
 * are extracted from the <b>colors</b> structure. The intensities will be in
 * the range 0 ­- 255.  Also works for null cells.
 *
 *  \param[in] n CELL to get color from
 *  \param[out] red red value
 *  \param[out] grn green value
 *  \param[out] blu blue value
 *  \param[in] colors Colors struct
 *  \return int
 */

int G_get_color(CELL n, int *red, int *grn, int *blu, struct Colors *colors)
{
    CELL cat;
    unsigned char r, g, b, set;

    cat = n;
    G_lookup_colors(&cat, &r, &g, &b, &set, 1, colors);

    *red = (int)r;
    *grn = (int)g;
    *blu = (int)b;

    return (int)set;
}


/**
 * \brief Gets color from raster.
 *
 * Looks up the rgb colors for
 * <em>rast</em> in the color table <em>colors</em>
 *
 *  \param[in] rast input raster map
 *  \param[out] red red value
 *  \param[out] grn green value
 *  \param[out] blu blue value
 *  \param[in] colors Colors struct
 *  \param[in] map_type type of map (CELL_TYPE,FCELL_TYPE,DCELL_TYPE)
 *  \return int
 */

int G_get_raster_color(const void *rast,
		       int *red, int *grn, int *blu,
		       struct Colors *colors, RASTER_MAP_TYPE map_type)
{
    unsigned char r, g, b, set;

    G_lookup_raster_colors(rast, &r, &g, &b, &set, 1, colors, map_type);

    *red = (int)r;
    *grn = (int)g;
    *blu = (int)b;

    return (int)set;
}


/**
 * \brief Gets color for a CELL raster.
 *
 * Looks up the rgb colors for CELL
 * <em>rast</em> in the color table <em>colors</em>
 *
 *  \param[in] rast input CELL raster
 *  \param[out] red red value
 *  \param[out] grn green value
 *  \param[out] blu blue value
 *  \param[in] colors Colors struct
 *  \return int
 */

int G_get_c_raster_color(const CELL * rast,
			 int *red, int *grn, int *blu, struct Colors *colors)
{
    return G_get_raster_color(rast, red, grn, blu, colors, CELL_TYPE);
}


/**
 * \brief Gets color for a FCELL raster.
 *
 *  Looks up the rgb colors for FCELL <em>rast</em> in the color table
 * <em>colors</em>
 *
 *  \param[in] rast input FCELL raster
 *  \param[out] red red value
 *  \param[out] grn green value
 *  \param[out] blu blue value
 *  \param[in] colors Colors struct
 *  \return int
 */

int G_get_f_raster_color(const FCELL * rast,
			 int *red, int *grn, int *blu, struct Colors *colors)
{
    return G_get_raster_color(rast, red, grn, blu, colors, FCELL_TYPE);
}


/**
 * \brief Gets color for a DCELL raster.
 *
 *  Looks up the rgb colors for DCELL <em>rast</em> in the color table
 * <em>colors</em>
 *
 *  \param[in] rast input DCELL raster
 *  \param[out] red red value
 *  \param[out] grn green value
 *  \param[out] blu blue value
 *  \param[in] colors Colors struct
 *  \return int
 */

int G_get_d_raster_color(const DCELL * rast,
			 int *red, int *grn, int *blu, struct Colors *colors)
{
    return G_get_raster_color(rast, red, grn, blu, colors, DCELL_TYPE);
}


/**
 * \brief  Gets color for null value.
 *
 * Puts the red, green, and blue components of <b>colors</b> for the
 * NULL-value into <b>red, grn, and blu</b>.
 *
 *  \param[out] red red value
 *  \param[out] grn green value
 *  \param[out] blu blue value
 *  \param[in] colors Colors struct
 *  \return
 */

void G_get_null_value_color(int *red, int *grn, int *blu,
			   const struct Colors *colors)
{
    if (colors->null_set) {
	*red = (int)colors->null_red;
	*grn = (int)colors->null_grn;
	*blu = (int)colors->null_blu;
    }
    else if (colors->undef_set) {
	*red = (int)colors->undef_red;
	*grn = (int)colors->undef_grn;
	*blu = (int)colors->undef_blu;
    }
    else
	*red = *blu = *grn = 255;	/* white */
}


/**
 * \brief Gets default color.
 *
 *  Puts the red, green, and blue components of the
 * <tt>"default"</tt> color into <b>red, grn, and blu</b>.
 *
 *  \param[out] red red value
 *  \param[out] grn green value
 *  \param[out] blu blue value
 *  \param[in] colors Colors struct
 *  \return
 */

void G_get_default_color(int *red, int *grn, int *blu,
			 const struct Colors *colors)
{
    if (colors->undef_set) {
	*red = (int)colors->undef_red;
	*grn = (int)colors->undef_grn;
	*blu = (int)colors->undef_blu;
    }
    else
	*red = *blu = *grn = 255;	/* white */
}