XQueryColor(3)

NAME

       XQueryColor, XQueryColors, XLookupColor, XParseColor - obtain color
       values

SYNTAX

       int XQueryColor(Display *display, Colormap colormap, XColor
              *def_in_out);

       int XQueryColors(Display *display, Colormap colormap, XColor
              defs_in_out[], int ncolors);

       Status XLookupColor(Display *display, Colormap colormap, char
              *color_name, XColor *exact_def_return, XColor
              *screen_def_return);

       Status XParseColor(Display *display, Colormap colormap, char *spec,
              XColor *exact_def_return);

ARGUMENTS

       colormap  Specifies the colormap.

       color_name
                 Specifies the color name string (for example, red) whose
                 color definition structure you want returned.

       def_in_out
                 Specifies and returns the RGB values for the pixel specified
                 in the structure.

       defs_in_out
                 Specifies and returns an array of color definition structures
                 for the pixel specified in the structure.

       display   Specifies the connection to the X server.

       exact_def_return
                 Returns the exact RGB values.

       ncolors   Specifies the number of XColor structures in the color defi-
                 nition array.

       screen_def_return
                 Returns the closest RGB values provided by the hardware.

       spec      Specifies the color name string; case is ignored.

       exact_def_return
                 Returns the exact color value for later use and sets the
                 DoRed, DoGreen, and DoBlue flags.

DESCRIPTION

       The XQueryColor function returns the current RGB value for the pixel in
       the XColor structure and sets the DoRed, DoGreen, and DoBlue flags.
       The XQueryColors function returns the RGB value for each pixel in each
       XColor structure and sets the DoRed, DoGreen, and DoBlue flags in each
       structure.

       XQueryColor and XQueryColors can generate BadColor and BadValue errors.

       The XLookupColor function looks up the string name of a color with
       respect to the screen associated with the specified colormap.  It
       returns both the exact color values and the closest values provided by
       the screen with respect to the visual type of the specified colormap.
       If the color name is not in the Host Portable Character Encoding, the
       result is implementation-dependent.  Use of uppercase or lowercase does
       not matter.  XLookupColor returns nonzero if the name is resolved; oth-
       erwise, it returns zero.

       The XParseColor function looks up the string name of a color with
       respect to the screen associated with the specified colormap.  It
       returns the exact color value.  If the color name is not in the Host
       Portable Character Encoding, the result is implementation-dependent.
       Use of uppercase or lowercase does not matter.  XParseColor returns
       nonzero if the name is resolved; otherwise, it returns zero.

       XLookupColor and XParseColor can generate BadColor error.

COLOR NAMES

       An RGB Device specification is identified by the prefix ``rgb:'' and
       conforms to the following syntax:

       rgb:<red>/<green>/<blue>

           <red>, <green>, <blue> := h | hh | hhh | hhhh
           h := single hexadecimal digits (case insignificant)

       Note that h indicates the value scaled in 4 bits, hh the value scaled
       in 8 bits, hhh the value scaled in 12 bits, and hhhh the value scaled
       in 16 bits, respectively.

       For backward compatibility, an older syntax for RGB Device is sup-
       ported, but its continued use is not encouraged.  The syntax is an ini-
       tial sharp sign character followed by a numeric specification, in one
       of the following formats:

       #RGB                (4 bits each)
       #RRGGBB             (8 bits each)
       #RRRGGGBBB          (12 bits each)
       #RRRRGGGGBBBB       (16 bits each)

       The R, G, and B represent single hexadecimal digits.  When fewer than
       16 bits each are specified, they represent the most significant bits of
       the value (unlike the ``rgb:'' syntax, in which values are scaled).
       For example, the string ``#3a7'' is the same as ``#3000a0007000''.

       An RGB intensity specification is identified by the prefix ``rgbi:''
       and conforms to the following syntax:

       rgbi:<red>/<green>/<blue>

       Note that red, green, and blue are floating-point values between 0.0
       and 1.0, inclusive.  The input format for these values is an optional
       sign, a string of numbers possibly containing a decimal point, and an
       optional exponent field containing an E or e followed by a possibly
       signed integer string.

       The standard device-independent string specifications have the follow-
       ing syntax:

       CIEXYZ:<X>/<Y>/<Z>
       CIEuvY:<u>/<v>/<Y>
       CIExyY:<x>/<y>/<Y>
       CIELab:<L>/<a>/<b>
       CIELuv:<L>/<u>/<v>
       TekHVC:<H>/<V>/<C>

       All of the values (C, H, V, X, Y, Z, a, b, u, v, y, x) are floating-
       point values.  The syntax for these values is an optional plus or minus
       sign, a string of digits possibly containing a decimal point, and an
       optional exponent field consisting of an ``E'' or ``e'' followed by an
       optional plus or minus followed by a string of digits.

DIAGNOSTICS

       BadColor  A value for a Colormap argument does not name a defined Col-
                 ormap.

       BadValue  Some numeric value falls outside the range of values accepted
                 by the request.  Unless a specific range is specified for an
                 argument, the full range defined by the argument's type is
                 accepted.  Any argument defined as a set of alternatives can
                 generate this error.

XQueryColor(3)

NAME

SYNTAX

ARGUMENTS

DESCRIPTION

COLOR NAMES

DIAGNOSTICS

SEE ALSO