Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/computing/software/gipsy/sub/pgshls.dc2 Дата изменения: Wed Oct 31 05:16:17 2001 Дата индексирования: Fri Jan 16 01:19:18 2009 Кодировка: Поисковые слова: solar eclipse

Name: PGSHLS

Purpose: set color representation using HLS system

Category: GRAPHICS

File: pgplot.src

Author: T.J. Pearson

Use: see description below.

Description:

SUBROUTINE PGSHLS (CI, CH, CL, CS)
INTEGER CI
REAL CH, CL, CS

Set color representation: i.e., define the color to be
associated with a color index. This routine is equivalent to
PGSCR, but the color is defined in the Hue-Lightness-Saturation
model instead of the Red-Green-Blue model. Hue is represented
by an angle in degrees, with red at 120, green at 240,
and blue at 0 (or 360). Lightness ranges from 0.0 to 1.0, with black
at lightness 0.0 and white at lightness 1.0. Saturation ranges from
0.0 (gray) to 1.0 (pure color). Hue is irrelevant when saturation
is 0.0.

Examples: H L S R G B
black any 0.0 0.0 0.0 0.0 0.0
white any 1.0 0.0 1.0 1.0 1.0
medium gray any 0.5 0.0 0.5 0.5 0.5
red 120 0.5 1.0 1.0 0.0 0.0
yellow 180 0.5 1.0 1.0 1.0 0.0
pink 120 0.7 0.8 0.94 0.46 0.46

Reference: SIGGRAPH Status Report of the Graphic Standards Planning
Committee, Computer Graphics, Vol.13, No.3, Association for
Computing Machinery, New York, NY, 1979. See also: J. D. Foley et al,
``Computer Graphics: Principles and Practice'', second edition,
Addison-Wesley, 1990, section 13.3.5.

Argument:
CI (input) : the color index to be defined, in the range 0-max.
If the color index greater than the device
maximum is specified, the call is ignored. Color
index 0 applies to the background color.
CH (input) : hue, in range 0.0 to 360.0.
CL (input) : lightness, in range 0.0 to 1.0.
CS (input) : saturation, in range 0.0 to 1.0.

Updates: Oct 16, 1998: JPT automatically extracted from source.