plscmap1la: Set cmap1 colors and alpha transparency using a piece-wise linear relationship

plscmap1la ( itype ,
  npts ,
  intensity ,
  coord1 ,
  coord2 ,
  coord3 ,
  alpha ,
  alt_hue_path );
 

This is a variant of plscmap1l that supports alpha channel transparency. It sets cmap1 colors using a piece-wise linear relationship between cmap1 intensity index (0.0-1.0) and position in HLS or RGB color space (see the section called “Color Map1”) with alpha transparency 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.

intensity (PLFLT_VECTOR, input)

A vector containing the cmap1 intensity index (0.0-1.0) in ascending order for each control point.

coord1 (PLFLT_VECTOR, input)

A vector containing the first coordinate (H or R) for each control point.

coord2 (PLFLT_VECTOR, input)

A vector containing the second coordinate (L or G) for each control point.

coord3 (PLFLT_VECTOR, input)

A vector containing the third coordinate (S or B) for each control point.

alpha (PLFLT_VECTOR, input)

A vector containing the alpha transparency value (0.0-1.0) for each control point.

alt_hue_path (PLBOOL_VECTOR, input)

A vector (with npts - 1 elements) containing the alternative interpolation method Boolean value for each control point interval. (alt_hue_path[i] refers to the interpolation interval between the i and i + 1 control points).

Redacted form: plscmap1la(itype, intensity, coord1, coord2, coord3, alpha, alt_hue_path)

This function is used in example 30.