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,   _Xconst   char   *color_name,   XColor
              *exact_def_return, XColor *screen_def_return);

       Status XParseColor(Display *display, Colormap colormap, _Xconst 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 definition 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; otherwise, 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 supported, but its  continued  use  is  not
       encouraged.  The syntax is an initial 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 following 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 Colormap.

       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.

SEE ALSO

       XAllocColor(3), XCreateColormap(3), XStoreColors(3)
       Xlib - C Language X Interface