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 pattern value converted from string.
                                      Must not be NULL.
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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 “.,-_” and spaces. If all goes well, TCL_OK is
       returned and a dash descriptor is stored in the variable pointed to by dashPtr.  If string does not  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 represents the number of pixels of  a  line
       segment.  Only  the  odd  segments  are  drawn  using  the  “outline” color. The other segments are drawn
       transparent.

       The second possible syntax is a character list containing only 5 possible characters “.,-_ ”.  The  space
       can  be used to enlarge the space between other line elements, and can not occur in the first position of
       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 between this syntax and the numeric is that it is shape-conserving. This  means  that
       all  values  in  the dash list will be multiplied by the line width before display. This ensures 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
       available; the last 2 examples will be displayed identically to the first one.

SEE ALSO

       canvas(3tk), Tk_CreateItemType(3tk)

KEYWORDS

       dash, conversion