Tcl8.6.15/Tk8.6.15 Documentation > Tk C API, version 8.6.15 > GetDash

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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

DESCRIPTION

SEE ALSO

KEYWORDS

NAME

SYNOPSIS

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.

DESCRIPTION

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

KEYWORDS