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.
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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 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 as the first position 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 is 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 available. The last 2 examples will be displayed identically as
       the first one.

KEYWORDS

       dash, conversion