Conversion between Colour systems

RGB to HLS

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                  | CALL  IGRTOH (CR,CB,CG,CH*,CL*,CS*) |
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Action: This routine convert a RGB colour into an HLS colour. Parameter Description:
CR
Red value 0.<=CR< =1.
CG
Green value 0.<=CG< =1.
CB
Blue value 0.<=CB< =1.
CH
Hue value 0.<=CH< =360.
CL
Light value 0.<=CL< =1.
CS
Saturation value 0.<=CS< =1.

HLS to RGB

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                  | CALL  IGHTOR (CH,CL,CS,CR*,CB*,CG*) |
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Action: This routine convert a HLS colour into an RGB colour. Parameter Description:
CH
Hue value 0.<=CH< =360.
CL
Light value 0.<=CL< =1.
CS
Saturation value 0.<=CS< =1.
CR
Red value 0.<=CR< =1.
CG
Green value 0.<=CG< =1.
CB
Blue value 0.<=CB< =1.