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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 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



Tk                                                   8.3                                       Tk_GetDash(3)