Doc/lib/libcolorsys.tex

   1 \section{\module{colorsys} ---
   2          Conversions between color systems}
   3
   4 \declaremodule{standard}{colorsys}
   5 \modulesynopsis{Conversion functions between RGB and other color systems.}
   6 \sectionauthor{David Ascher}{da@python.net}
   7
   8 The \module{colorsys} module defines bidirectional conversions of
   9 color values between colors expressed in the RGB (Red Green Blue)
  10 color space used in computer monitors and three other coordinate
  11 systems: YIQ, HLS (Hue Lightness Saturation) and HSV (Hue Saturation
  12 Value).  Coordinates in all of these color spaces are floating point
  13 values.  In the YIQ space, the Y coordinate is between 0 and 1, but
  14 the I and Q coordinates can be positive or negative.  In all other
  15 spaces, the coordinates are all between 0 and 1.
  16
  17 More information about color spaces can be found at
  18 \url{http://www.inforamp.net/\%7epoynton/ColorFAQ.html}.
  19
  20 The \module{colorsys} module defines the following functions:
  21
  22 \begin{funcdesc}{rgb_to_yiq}{r, g, b}
  23 Convert the color from RGB coordinates to YIQ coordinates.
  24 \end{funcdesc}
  25
  26 \begin{funcdesc}{yiq_to_rgb}{y, i, q}
  27 Convert the color from YIQ coordinates to RGB coordinates.
  28 \end{funcdesc}
  29
  30 \begin{funcdesc}{rgb_to_hls}{r, g, b}
  31 Convert the color from RGB coordinates to HLS coordinates.
  32 \end{funcdesc}
  33
  34 \begin{funcdesc}{hls_to_rgb}{h, l, s}
  35 Convert the color from HLS coordinates to RGB coordinates.
  36 \end{funcdesc}
  37
  38 \begin{funcdesc}{rgb_to_hsv}{r, g, b}
  39 Convert the color from RGB coordinates to HSV coordinates.
  40 \end{funcdesc}
  41
  42 \begin{funcdesc}{hsv_to_rgb}{h, s, v}
  43 Convert the color from HSV coordinates to RGB coordinates.
  44 \end{funcdesc}
  45
  46 Example:
  47
  48 \begin{verbatim}
  49 >>> import colorsys
  50 >>> colorsys.rgb_to_hsv(.3, .4, .2)
  51 (0.25, 0.5, 0.4)
  52 >>> colorsys.hsv_to_rgb(0.25, 0.5, 0.4)
  53 (0.3, 0.4, 0.2)
  54 \end{verbatim}