Manual Pages for UNIX Operating System command usage for man Tk_GetVisual

Tk Library Procedures                           Tk_GetVisual(3TK)



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NAME
     Tk_GetVisual - translate from string to visual

SYNOPSIS
     #include 

     Visual *
     Tk_GetVisual(interp, tkwin, string, depthPtr, colormapPtr)

ARGUMENTS
     Tcl_Interp   *interp        (in)      Interpreter to use for
                                           error reporting.

     Tk_Window    tkwin          (in)      Token  for  window  in
                                           which  the visual will
                                           be used.

     CONST char   *string        (in)      String that identifies
                                           the   desired  visual.
                                           See  below  for  valid
                                           formats.

     int          *depthPtr      (out)     Depth   of    returned
                                           visual   gets   stored
                                           here.

     Colormap     *colormapPtr   (out)     If  non-NULL  then   a
                                           suitable  colormap for
                                           visual  is  found  and
                                           its    identifier   is
                                           stored here.
_________________________________________________________________


DESCRIPTION
     Tk_GetVisual takes a string  description  of  a  visual  and
     finds a suitable X Visual for use in tkwin, if there is one.
     It returns a pointer to  the  X  Visual  structure  for  the
     visual  and  stores  the  number of bits per pixel for it at
     *depthPtr.  If string is unrecognizable or  if  no  suitable
     visual   could   be   found,   then  NULL  is  returned  and
     Tk_GetVisual leaves an error message in interp->result.   If
     colormap  is  non-NULL  then  Tk_GetVisual  also  locates an
     appropriate colormap for use  with  the  result  visual  and
     stores its X identifier at *colormapPtr.

     The string argument specifies the desired visual in  one  of
     the following ways:

     class depth    The string consists of a class name  followed



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Tk Library Procedures                           Tk_GetVisual(3TK)



                    by an integer depth, with any amount of white
                    space (including  none)  in  between.   class
                    selects  what  sort  of visual is desired and
                    must be one of directcolor, grayscale, greys-
                    cale,  pseudocolor,  staticcolor, staticgray,
                    staticgrey, or truecolor, or a unique  abbre-
                    viation.   depth  specifies how many bits per
                    pixel are needed for the visual.   If  possi-
                    ble,  Tk_GetVisual  will return a visual with
                    this depth; if there  is  no  visual  of  the
                    desired  depth  then Tk_GetVisual looks first
                    for a visual with  greater  depth,  then  one
                    with less depth.

     default        Use the default visual for tkwin's screen.

     pathName       Use the visual for the window given by  path-
                    Name.   pathName must be the name of a window
                    on the same screen as tkwin.

     number         Use the visual whose X identifier is number.

     best ?depth?   Choose the ``best  possible''  visual,  using
                    the  following  rules, in decreasing order of
                    priority:  (a) a visual that has exactly  the
                    desired  depth  is best, followed by a visual
                    with greater depth  than  requested  (but  as
                    little  extra  as  possible),  followed  by a
                    visual with less depth than requested (but as
                    great  a  depth as possible); (b) if no depth
                    is  specified,  then  the  deepest  available
                    visual  is  chosen; (c) pseudocolor is better
                    than  truecolor  or  directcolor,  which  are
                    better than staticcolor, which is better than
                    staticgray  or  grayscale;  (d)  the  default
                    visual  for  the  screen  is  better than any
                    other visual.


CREDITS
     The idea for Tk_GetVisual,  and  the  first  implementation,
     came from Paul Mackerras.


KEYWORDS
     colormap, screen, visual

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:





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Tk Library Procedures                           Tk_GetVisual(3TK)



     _______________________________________
    |   ATTRIBUTE TYPE   |  ATTRIBUTE VALUE|
    |____________________|__________________|_
    | Availability       |  runtime/tk-8   |
    |____________________|__________________|_
    | Interface Stability|  Uncommitted    |
    |____________________|_________________|

NOTES
     Source for Tk is available on http://opensolaris.org.













































Tk                      Last change: 4.0                        3