1XQueryColor(3)                  XLIB FUNCTIONS                  XQueryColor(3)
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NAME

6       XQueryColor,  XQueryColors,  XLookupColor,  XParseColor  - obtain color
7       values
8

SYNTAX

10       int   XQueryColor(Display   *display,   Colormap    colormap,    XColor
11              *def_in_out);
12
13       int    XQueryColors(Display   *display,   Colormap   colormap,   XColor
14              defs_in_out[], int ncolors);
15
16       Status XLookupColor(Display *display, Colormap colormap,  _Xconst  char
17              *color_name,  XColor  *exact_def_return,  XColor *screen_def_re‐
18              turn);
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20       Status XParseColor(Display *display, Colormap  colormap,  _Xconst  char
21              *spec, XColor *exact_def_return);
22

ARGUMENTS

24       colormap  Specifies the colormap.
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26       color_name
27                 Specifies  the  color  name  string  (for example, red) whose
28                 color definition structure you want returned.
29
30       def_in_out
31                 Specifies and returns the RGB values for the pixel  specified
32                 in the structure.
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34       defs_in_out
35                 Specifies and returns an array of color definition structures
36                 for the pixel specified in the structure.
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38       display   Specifies the connection to the X server.
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40       exact_def_return
41                 Returns the exact RGB values.
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43       ncolors   Specifies the number of XColor structures in the color  defi‐
44                 nition array.
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46       screen_def_return
47                 Returns the closest RGB values provided by the hardware.
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49       spec      Specifies the color name string; case is ignored.
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51       exact_def_return
52                 Returns  the  exact  color  value  for later use and sets the
53                 DoRed, DoGreen, and DoBlue flags.
54

DESCRIPTION

56       The XQueryColor function returns the current RGB value for the pixel in
57       the  XColor  structure  and  sets the DoRed, DoGreen, and DoBlue flags.
58       The XQueryColors function returns the RGB value for each pixel in  each
59       XColor  structure and sets the DoRed, DoGreen, and DoBlue flags in each
60       structure.
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62
63       XQueryColor and XQueryColors can generate BadColor and BadValue errors.
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65       The XLookupColor function looks up the string name of a color with  re‐
66       spect to the screen associated with the specified colormap.  It returns
67       both the exact color values and the  closest  values  provided  by  the
68       screen  with  respect to the visual type of the specified colormap.  If
69       the color name is not in the Host Portable Character Encoding, the  re‐
70       sult  is  implementation-dependent.  Use of uppercase or lowercase does
71       not matter.  XLookupColor returns nonzero if the name is resolved; oth‐
72       erwise, it returns zero.
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74       The  XParseColor  function looks up the string name of a color with re‐
75       spect to the screen associated with the specified colormap.  It returns
76       the  exact  color value.  If the color name is not in the Host Portable
77       Character Encoding, the result is implementation-dependent.  Use of up‐
78       percase  or  lowercase does not matter.  XParseColor returns nonzero if
79       the name is resolved; otherwise, it returns zero.
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81       XLookupColor and XParseColor can generate BadColor error.
82

COLOR NAMES

84       An RGB Device specification is identified by the prefix “rgb:” and con‐
85       forms to the following syntax:
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87       rgb:<red>/<green>/<blue>
88
89           <red>, <green>, <blue> := h | hh | hhh | hhhh
90           h := single hexadecimal digits (case insignificant)
91
92       Note  that  h indicates the value scaled in 4 bits, hh the value scaled
93       in 8 bits, hhh the value scaled in 12 bits, and hhhh the  value  scaled
94       in 16 bits, respectively.
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96       For  backward  compatibility,  an  older  syntax for RGB Device is sup‐
97       ported, but its continued use is not encouraged.  The syntax is an ini‐
98       tial  sharp  sign character followed by a numeric specification, in one
99       of the following formats:
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101       #RGB            (4 bits each)
102       #RRGGBB         (8 bits each)
103       #RRRGGGBBB      (12 bits each)
104       #RRRRGGGGBBBB   (16 bits each)
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106       The R, G, and B represent single hexadecimal digits.  When  fewer  than
107       16 bits each are specified, they represent the most significant bits of
108       the value (unlike the “rgb:” syntax, in which values are scaled).   For
109       example, the string “#3a7” is the same as “#3000a0007000”.
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111       An  RGB intensity specification is identified by the prefix “rgbi:” and
112       conforms to the following syntax:
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114       rgbi:<red>/<green>/<blue>
115
116       Note that red, green, and blue are floating-point  values  between  0.0
117       and  1.0,  inclusive.  The input format for these values is an optional
118       sign, a string of numbers possibly containing a decimal point,  and  an
119       optional  exponent  field  containing  an E or e followed by a possibly
120       signed integer string.
121
122       The standard device-independent string specifications have the  follow‐
123       ing syntax:
124
125       CIEXYZ:<X>/<Y>/<Z>
126       CIEuvY:<u>/<v>/<Y>
127       CIExyY:<x>/<y>/<Y>
128       CIELab:<L>/<a>/<b>
129       CIELuv:<L>/<u>/<v>
130       TekHVC:<H>/<V>/<C>
131
132       All  of  the  values (C, H, V, X, Y, Z, a, b, u, v, y, x) are floating-
133       point values.  The syntax for these values is an optional plus or minus
134       sign,  a  string  of digits possibly containing a decimal point, and an
135       optional exponent field consisting of an “E” or “e” followed by an  op‐
136       tional plus or minus followed by a string of digits.
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DIAGNOSTICS

139       BadColor  A  value for a Colormap argument does not name a defined Col‐
140                 ormap.
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142       BadValue  Some numeric value falls outside the range of values accepted
143                 by  the request.  Unless a specific range is specified for an
144                 argument, the full range defined by the  argument's  type  is
145                 accepted.   Any argument defined as a set of alternatives can
146                 generate this error.
147

SEE ALSO

149       XAllocColor(3), XCreateColormap(3), XStoreColors(3)
150       Xlib - C Language X Interface
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154X Version 11                     libX11 1.8.1                   XQueryColor(3)
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