Tk_GetScrollInfo(3tk)

💖 Tk_GetScrollInfo — bestie edition 💖

okay so this is the Tk library procedure page for Tk_GetScrollInfoObj and Tk_GetScrollInfo, aka the little gremlins that parse arguments for scrolling commands. yes we are in the Tk manual, section 3tk, and no this is not scary, i promise, come sit with me 🫶

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✨ NAME ✨

Tk_GetScrollInfoObj, Tk_GetScrollInfo — parse arguments for scrolling commands 💅

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🌸 SYNOPSIS 🌸

#include <tk.h>

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

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

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🎀 ARGUMENTS 🎀

• Tcl_Interp *interp (in) — the interpreter we use to report errors, bestie. if something goes wrong, this is where the drama gets written down 😭
• Tcl_Size objc (in) — how many Tcl_Obj's are chillin in the objv array ✨
• Tcl_Obj *const * objv (in) — the argument objects. these represent the entire widget command, and like, typically the first word is the widget name and the second word is typically xview or yview. periodt.
• int argc (in) — how many strings are in the argv array 🌸
• const char ** argv (in) — the argument strings. same vibe as objv: they represent the entire widget command, first word usually the widget name, second word usually xview or yview 🦋
• double *fractionPtr (out) — gets filled in with the fraction from the moveto option, if there is one 💖
• int *stepsPtr (out) — gets filled in with the line or page count from the scroll option, if there is one. heads up: the value may be negative 👀

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🌈 DESCRIPTION 🌈

Tk_GetScrollInfoObj parses the arguments that widget scrolling commands like xview and yview expect. it receives the whole entire list of words that make up a widget command, and then it parses the words starting with objv[2] — yes, it just skips right past the first two, main character behaviour honestly 👑

the words starting with objv[2] must have one of these forms, no exceptions:

moveto fraction
scroll number pages
scroll number units

any of the moveto, scroll, pages, and units keywords may be abbreviated. slay, shorthand rights 🎀

so here's the tea on what gets returned:

• if objv has the moveto form → TK_SCROLL_MOVETO is returned as the result, and *fractionPtr gets 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 gets filled in with the number value, which must be an integer or a float. but bestie, listen: if it is a float, then it gets converted to an integer, rounded away from 0 💅
• if an error happens while parsing the arguments → TK_SCROLL_ERROR is returned, and an error message gets left in interpreter interp's result 😭

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Tk_GetScrollInfo is identical in function to Tk_GetScrollInfoObj. literally the same girl, different fit. the one difference: Tk_GetScrollInfo accepts string arguments, which makes it more appropriate for use with legacy widgets 🧚

not me giving you the old-school version too because some widgets are still out here living their vintage era 🙈

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👑 KEYWORDS 👑

parse, scrollbar, scrolling command, xview, yview

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k bye ily, go parse some scroll arguments 🦋✨

this was brought to you by Tk, version 8.0 — mwah 💋 🍓