MirOS Manual: XLookupColor(3), XParseColor(3), XQueryColor(3), XQueryColors(3)


XQueryColor(3X11)        XLIB FUNCTIONS         XQueryColor(3X11)

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 struc-
               ture.

     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.

XFree86                   Version 4.5.0                         1

XQueryColor(3X11)        XLIB FUNCTIONS         XQueryColor(3X11)

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 Bad-
     Value errors.

     The XLookupColor function looks up the string name of a
     color with respect to the screen associated with the speci-
     fied 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)

XFree86                   Version 4.5.0                         2

XQueryColor(3X11)        XLIB FUNCTIONS         XQueryColor(3X11)

     #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:'' syn-
     tax, 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 gen-
               erate this error.

SEE ALSO

     XAllocColor(3X11), XCreateColormap(3X11), XStoreColors(3X11)
     Xlib - C Language X Interface

XFree86                   Version 4.5.0                         3

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