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