plscmap1la: Set color map1 colors using a piece-wise linear relationship

plscmap1la (itype, npts, pos, coord1, coord2, coord3, coord4, rev);

This is a version of plscmap1l that supports alpha transparency. It sets color map1 colors using a piece-wise linear relationship between position in the color map (from 0 to 1) and position in HLS or RGB color space (see the Section called Color Map1 in Chapter 3) with alpha value (0.0 - 1.0). It may be called at any time.

itype (PLBOOL, input)

true: RGB, false: HLS.

npts (PLINT, input)

number of control points

pos (PLFLT *, input)

position for each control point (between 0.0 and 1.0, in ascending order)

coord1 (PLFLT *, input)

first coordinate (H or R) for each control point

coord2 (PLFLT *, input)

second coordinate (L or G) for each control point

coord3 (PLFLT *, input)

third coordinate (S or B) for each control point

coord4 (PLFLT *, input)

fourth coordinate, the alpha value for each control point

rev (PLBOOL: *, input)

reverse flag for each control point. (rev[i] refers to the interpolation interval between the i and i + 1 control points).

This function is used in example 30.