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 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