Tk_GetDash(3) Tk Library Procedures Tk_GetDash(3)
NAME
Tk_GetDash - convert from string to valid dash structure.
SYNOPSIS
#include <tk.h>
int
Tk_GetDash(interp, string, dashPtr)
ARGUMENTS
Interpreter to use for error reporting. Textual value to be converted.
Points to place to store the dash pattern value converted 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 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 repre-
sents the number of pixels of a line segment. Only the odd segments are
drawn using the color. The other segments are drawn transparent.
The second possible syntax is a character list containing only 5 possi-
ble 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 avail-
able. The last 2 examples will be displayed identically as the first
one.
KEYWORDS
dash, conversion
Tk 8.3 Tk_GetDash(3)
GetDash 8.5.4 - Generated Sat Aug 23 16:22:19 CDT 2008