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