/*****************************************************************************
*                                                                            *
*   HSV.SPL   Copyright (C) 2018 DSP Development Corporation                 *
*                               All Rights Reserved                          *
*                                                                            *
*   Author:      Randy Race                                                  *
*                                                                            *
*   Synopsis:    Generate red, yellow, green, cyan, blue, magenta, red cmap  *
*                                                                            *
*   Revisions:   30 Mar 2018  RRR  Creation                                  *
*                                                                            *
*****************************************************************************/


#if @HELP_HSV

    HSV

    Purpose: Generates a red, yellow, green, cyan, blue, magenta, red colormap.

    Syntax:  HSV(len)

               len - optional colormap length, defaults to
                     the length of the current colormap


    Returns: A table of RGB triples suitable for the SETCOLORMAP function.

    Example:
             clen = length(getcolormap());
             density(ravel(rep(0..(clen-1), 32), clen)');
             string();

             Creates a table of 32 x colormap length RBG values and
             displays the resulting colors. The resulting image is a
             vertical plot of colors ranging from red (lowest) to
             yellow, green, cyan, blue, magenta and back to red.

    Example:
             hsv(256);showcmap

             Creates a table of 32 x 256 length RBG values and
             displays the resulting colors. The resulting image is a
             vertical plot of colors ranging from red (lowest) to
             yellow, green, cyan, blue, magenta and back to red.

    Remarks:
             HSV() by itself sets the colormap and shading.

             a = hsv() or setcolormap(hsv()) returns the rgb values.
             In this case, use SETSHADING to make the new colormap
             take effect on an existing density or 2D plot.

             HSV creates a colormap by linearly varying the hue portion of a
             colormap where the saturation and lightness components
             remain constant.

    See Also:
             Autumn
             Bone
             Cool
             Copper
             Gray
             Hot
             Hsv2rgb
             Parula
             Pink
             Rainbow
             Setcolormap
             Setshading
             Showcmap
             Spring
             Summer
             Winter
#endif


/* hsv colormap */
hsv(cmaplen)
{
        local rgb, hsv;

        if (argc < 1)
        {
                cmaplen = length(getcolormap());
        }

        /* HSV colors */
        hsv = (0..(cmaplen - 1)) / max(1, cmaplen - 1);

        /* convert to rgb */
        rgb = hsv2rgb(ravel(hsv, ones(cmaplen, 2)));

        if (outargc == 0)
        {
                /* set the colormap and shading */
                setplotshading(rgb);
        }
        else
        {
                /* return the colormap */
                setrgbprops(rgbp);

                return(rgb);
        }
}