XQueryColor(3X)                                   XQueryColor(3X)



NAME
     XQueryColor, XQueryColors, XLookupColor - get color values

SYNOPSIS
     XQueryColor (display, colormap, def-return)
     Display *display;
     Colormap colormap;
     XColor *def-return;

     XQueryColors (display, colormap, defs-return, ncolors)
     Display *display;
     Colormap colormap;
     XColor defs-return[];
     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;

DESCRIPTION
     The XQueryColor and XQueryColors functions return the red,
     green, and blue (RGB) color values stored in the specified
     colormap for the pixel value passed in the pixel member of
     the XColor structure(s).  The values returned for an unallo-
     cated entry are undefined.  The XQueryColor and XQueryColors
     functions also set the flags member in the XColor structure
     to all three colors.

     The XLookupColor function looks up the string name of a
     color with respect to the screen associated with the speci-
     fied colormap.  It then returns both the exact color values
     as well as the closest values provided by the screen, with
     respect to the visual type of the specified colormap.  You
     should use ISO Latin-1 encoding; case is ignored.  XLookup-
     Color returns nonzero if the name exists in the color data-
     base, and zero if it does not exist.

   Arguments
     These functions accept the following arguments:

     colormap
             Specifies the colormap ID.

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

     def-return
             Specifies or returns the RGB values for the pixel



November, 1990                                                  1

XQueryColor(3X)                                   XQueryColor(3X)



             specified in the structure.

     defs-return
             Specifies or returns an array of color definition
             structures.

     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.

ERRORS
     BadColor
             A value for a Colormap argument does not name a de-
             fined colormap.

     BadValue
             A numeric value falls outside the range of values
             accepted by the request.  Unless a range is speci-
             fied 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.

     The XQueryColor and XQueryColors functions can generate Bad-
     Color and BadValue errors.

SEE ALSO
     XAllocColor(3X), XCreateColormap(3X), XStoreColors(3X)

     Xlib - C Language Interface



















2                                                  November, 1990