Tk_GetScrollInfo

Section: Tk Library Procedures (3)
Updated: 8.0
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NAME

Tk_GetScrollInfoObj, Tk_GetScrollInfo - parse arguments for scrolling commands

SYNOPSIS

#include <tk.h>

int
Tk_GetScrollInfoObj(interp, objc, objv, fractionPtr, stepsPtr)

int
Tk_GetScrollInfo(interp, argc, argv, fractionPtr, stepsPtr)

ARGUMENTS

Tcl_Interp *interp (in) Interpreter to use for error reporting.

int objc (in) Number of Tcl_Obj's in objv array.

Tcl_Obj *const objv[] (in) Argument objects. These represent the entire widget command, of which the first word is typically the widget name and the second word is typically xview or yview.

int argc (in) Number of strings in argv array.

const char *argv[] (in) Argument strings. These represent the entire widget command, of which the first word is typically the widget name and the second word is typically xview or yview.

double *fractionPtr (out) Filled in with fraction from moveto option, if any.

int *stepsPtr (out) Filled in with line or page count from scroll option, if any. The value may be negative.

DESCRIPTION

Tk_GetScrollInfoObj parses the arguments expected by widget scrolling commands such as xview and yview. It receives the entire list of words that make up a widget command and parses the words starting with objv[2]. The words starting with objv[2] must have one of the following forms:


moveto fraction
scroll number units
scroll number pages

Any of the moveto, scroll, units, and pages keywords may be abbreviated. If objv has the moveto form, TK_SCROLL_MOVETO is returned as result and *fractionPtr is filled in with the fraction argument to the command, which must be a proper real value. If objv has the scroll form, TK_SCROLL_UNITS or TK_SCROLL_PAGES is returned and *stepsPtr is filled in with the number value, which must be a proper integer. If an error occurs in parsing the arguments, TK_SCROLL_ERROR is returned and an error message is left in interpreter interp's result.

Tk_GetScrollInfo is identical in function to Tk_GetScrollInfoObj. However, Tk_GetScrollInfo accepts string arguments, making it more appropriate for use with legacy widgets.

KEYWORDS

parse, scrollbar, scrolling command, xview, yview