Tk_GetScrollInfo manual page - Tk Library Procedures

Tcl 8.7/Tk8.7a5 Documentation > Tk C API > GetScroll

Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl C API | Tk C API

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

DESCRIPTION

KEYWORDS

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.

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 pages
scroll number units

Any of the moveto, scroll, pages, and units 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_PAGES or TK_SCROLL_UNITS is returned and *stepsPtr is filled in with the number value, which must be a integer or a float, but if it is a float then it is converted to an integer, rounded away from 0. 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