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)        Interpreter to use for error reporting.
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19       const char *string (in)        Textual value to be converted.
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21       Tk_Dash *dashPtr (out)         Points  to  place to store the dash pat‐
22                                      tern value converted from  string.  Must
23                                      not be NULL.
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DESCRIPTION

27       These  procedure  parses  the  string  and  fills  in the result in the
28       Tk_Dash structure. The string can be a list of integers or a  character
29       string  containing  only “.,-_” and spaces. If all goes well, TCL_OK is
30       returned and a dash descriptor is stored in the variable pointed to  by
31       dashPtr.   If  string does not have the proper syntax then TCL_ERROR is
32       returned, an error message is left in  the  interpreter's  result,  and
33       nothing is stored at *dashPtr.
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35       The  first  possible  syntax is a list of integers. Each element repre‐
36       sents the number of pixels of a line segment. Only the odd segments are
37       drawn using the “outline” color. The other segments are drawn transpar‐
38       ent.
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40       The second possible syntax is a character list containing only 5 possi‐
41       ble  characters  “.,-_  ”.   The space can be used to enlarge the space
42       between other line elements, and can not occur in the first position of
43       the string. Some examples:
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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 between this syntax and the numeric is that it is
53       shape-conserving. This means that all values in the dash list  will  be
54       multiplied  by  the  line  width  before display. This ensures that “.”
55       will always be displayed as a dot and “-” always as a  dash  regardless
56       of the 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  to  the  first
62       one.
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SEE ALSO

65       canvas(n), Tk_CreateItemType(3)
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KEYWORDS

68       dash, conversion
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72Tk                                    8.3                        Tk_GetDash(3)