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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.
                                      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(n), Tk_CreateItemType(3)


KEYWORDS

       dash, conversion

Tk                                    8.3                        Tk_GetDash(3)

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