GetDash

Tk_GetDash(3)                Tk Library Procedures               Tk_GetDash(3)



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NAME
       Tk_GetDash - convert from string to valid dash structure.

SYNOPSIS
       #include <tk.h>

       int
       Tk_GetDash(interp, string, dashPtr)

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

       CONST char *         string(in)
                                      Textual value to be converted.

       Tk_Dash   *dashPtr   (out)     Points to place to store the  dash  pat-
                                      tern value converted from string.
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DESCRIPTION
       These  procedure  parses  the  string  and  fills  in the result in the
       Tk_Dash structure. The string can be a list of integers or a  character
       string  containing  only  [.,-_] or spaces. If all goes well, TCL_OK is
       returned. If string doesn't have the proper syntax  then  TCL_ERROR  is
       returned,  an  error  message  is left in the interpreter's result, and
       nothing is stored at *dashPtr.

       The first possible syntax is a list of integers.  Each  element  repre-
       sents the number of pixels of a line segment. Only the odd segments are
       drawn using the "outline" color. The other segments are drawn transpar-
       ent.

       The second possible syntax is a character list containing only 5 possi-
       ble characters [.,-_ ]. The space can be  used  to  enlarge  the  space
       between other line elements, and can not occur as the first posibion in
       the string. Some examples:
           -dash .     = -dash {2 4}
           -dash -     = -dash {6 4}
           -dash -.    = -dash {6 4 2 4}
           -dash -..   = -dash {6 4 2 4 2 4}
           -dash {. }  = -dash {2 8}
           -dash ,     = -dash {4 4}

       The main difference of this syntax with the  previous  is  that  it  it
       shape-conserving.  This  means that all values in the dash list will be
       multiplied by the line width before display. This assures that "." will
       always be displayed as a dot and "-" always as a dash regardless of the
       line width.

       On systems where only a limited set of dash patterns, the dash  pattern
       will be displayed as the most close dash pattern that is available. For
       example, on Windows only the first 4 of the above examples  are  avail-
       able.  The  last  2 examples will be displayed identically as the first
       one.


KEYWORDS
       dash, conversion



Tk                                    8.3                        Tk_GetDash(3)