1Tk_GetDash(3)                Tk Library Procedures               Tk_GetDash(3)
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NAME

8       Tk_GetDash - convert from string to valid dash structure.
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SYNOPSIS

11       #include <tk.h>
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13       int
14       Tk_GetDash(interp, string, dashPtr)
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ARGUMENTS

17       Tcl_Interp           *interp(in)
18                                      Interpreter to use for error reporting.
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20       CONST char *         string(in)
21                                      Textual value to be converted.
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23       Tk_Dash   *dashPtr   (out)     Points  to  place to store the dash pat‐
24                                      tern value converted from string.
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DESCRIPTION

29       These procedure parses the string  and  fills  in  the  result  in  the
30       Tk_Dash  structure. The string can be a list of integers or a character
31       string containing only [.,-_] or spaces. If all goes  well,  TCL_OK  is
32       returned.  If  string  doesn't have the proper syntax then TCL_ERROR is
33       returned, an error message is left in  the  interpreter's  result,  and
34       nothing is stored at *dashPtr.
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36       The  first  possible  syntax is a list of integers. Each element repre‐
37       sents the number of pixels of a line segment. Only the odd segments are
38       drawn using the "outline" color. The other segments are drawn transpar‐
39       ent.
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41       The second possible syntax is a character list containing only 5 possi‐
42       ble  characters  [.,-_  ].  The  space can be used to enlarge the space
43       between other line elements, and can not occur as the first posibion in
44       the string. Some examples:
45           -dash .     = -dash {2 4}
46           -dash -     = -dash {6 4}
47           -dash -.    = -dash {6 4 2 4}
48           -dash -..   = -dash {6 4 2 4 2 4}
49           -dash {. }  = -dash {2 8}
50           -dash ,     = -dash {4 4}
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52       The  main  difference  of  this  syntax with the previous is that it it
53       shape-conserving. This means that all values in the dash list  will  be
54       multiplied by the line width before display. This assures that "." will
55       always be displayed as a dot and "-" always as a dash regardless of the
56       line width.
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58       On  systems where only a limited set of dash patterns, the dash pattern
59       will be displayed as the most close dash pattern that is available. For
60       example,  on  Windows only the first 4 of the above examples are avail‐
61       able. The last 2 examples will be displayed identically  as  the  first
62       one.
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KEYWORDS

66       dash, conversion
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70Tk                                    8.3                        Tk_GetDash(3)
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