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 con
verted.
Tk_Dash *dashPtr (out) Points to place to store
the dash pattern value con
verted from string.
_________________________________________________________________
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
doesn't 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 ele
ment 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 posibion in the string. Some exam
ples:
-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 it shape-conserving. This means that all values in
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 pat
tern 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
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