XQueryColor, XQueryColors, XLookupColor, XParseColor -
       obtain color values


SYNTAX

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

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

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

       Status XParseColor(display, colormap, spec,
       exact_def_return)
               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 defini-
                 tion 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
       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 struc-
       ture 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 spec-
       ified 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 spec-
       ified 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)
       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 pos-
       sibly 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 spe-
                 cific 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(3X11), XCreateColormap(3X11), XStoreCol-
       ors(3X11)
       Xlib - C Language X Interface



X Version 11               Release 6.4                          1