XLookupColor()XLookupColor()NameXLookupColor – get database RGB values and closest hardware-supported
RGB values from color name.
Synopsis
Status XLookupColor(display, colormap, colorname, exact_def_return,
screen_def_return)
Display *display;
Colormap colormap;
char *colorname;
XColor *exact_def_return, *screen_def_return;
Arguments
display Specifies a connection to an X server; returned from
XOpenDisplay().
colormap Specifies the colormap.
colorname Specifies a color name string (for example "red"). Upper‐
case or lowercase does not matter. If the color name is
not in the Host Portable Character Encoding, the result is
implementation-dependent.
exact_def_return
Returns the exact RGB values for the specified color name
from the /usr/lib/X11/rgb database.
screen_def_return
Returns the closest RGB values possible on the hardware.
Returns
Zero on failure, non-zero on success.
DescriptionXLookupColor() looks up RGB values for a color given the colorname
string. It returns both the exact color values and the closest values
possible on tthe screen specified by colormap.
XLookupColor() returns non-zero if colorname exists in the RGB database
or zero if it does not exist.
To determine the exact RGB values, XLookupColor() uses a database on
the X server. On UNIX, this database is /usr/lib/X11/rgb. To read the
colors provided by the database on a UNIX-based system, see
/usr/lib/X11/rgb.txt. The location, name, and contents of this file
are server-dependent.
For more information see Volume One, Chapter 7, Color, and Appendix D,
The Server-side Color Database, in this volume.
Errors
BadName Color name not in database.
BadColor Invalid colormap.
Structures
typedef struct {
unsigned long pixel;
unsigned short red, green, blue;
char flags; /* DoRed, DoGreen, DoBlue */
char pad;
} XColor;
See AlsoXBlackPixel(), XWhitePixel(), XAllocColor(), XAllocColorCells(), XAl‐
locColorPlanes(), XAllocNamedColor(), XFreeColors(), XParseColor(),
XQueryColor(), XQueryColors(), XStoreColor(), XStoreColors(), XStore‐
NamedColor().
Xlib - Color Cells XLookupColor()