Tk_FontId(3)

okay bestie, this is the Tk Library Procedures page for Tk_FontId(3) 💖 and it’s literally your cheat sheet for three font accessor functions. no cap, every detail is staying.

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✨ NAME ✨

okay so this page is about three accessor functions for fonts: Tk_FontId, Tk_GetFontMetrics, and Tk_PostscriptFontName. slay.

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🎀 SYNOPSIS 🎀

here’s the copy-paste magic, bestie:

#include <tk.h>

Font
Tk_FontId(tkfont)

Tk_GetFontMetrics(tkfont, fmPtr)

int
Tk_PostscriptFontName(tkfont, dsPtr)

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💅 ARGUMENTS 💅

• Tk_Font tkfont (in) — the opaque font token being queried. it must have been returned by a previous call to Tk_GetFont.
• Tk_FontMetrics *fmPtr (out) — pointer to the structure where the font metrics for tkfont will be stored. see DATA STRUCTURES below for the details, iykyk.
• Tcl_DString *dsPtr (out) — pointer to an initialized Tcl_DString to which the name of the Postscript font that corresponds to tkfont will be appended.

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✨ DESCRIPTION ✨

given a tkfont, Tk_FontId returns the token that should be selected into an XGCValues structure in order to construct a graphics context that can be used to draw text in the specified font. iconic behavior.

Tk_GetFontMetrics computes the ascent, descent, and linespace of the tkfont in pixels and stores those values in the structure pointed to by fmPtr. these values can be used in computations such as to space multiple lines of text, to align the baselines of text in different fonts, and to vertically align text in a given region. see the documentation for the font command for definitions of the terms ascent, descent, and linespace, used in font metrics.

Tk_PostscriptFontName maps a tkfont to the corresponding Postscript font name that should be used when printing. the return value is the size in points of the tkfont, and the Postscript font name is appended to dsPtr. DsPtr must refer to an initialized Tcl_DString. 🫶

given a “reasonable” Postscript printer, these screen font families should print correctly:

• Avant Garde
• Arial
• Bookman
• Courier
• Courier New
• Geneva
• Helvetica
• Monaco
• New Century Schoolbook
• New York
• Palatino
• Symbol
• Times
• Times New Roman
• Zapf Chancery
• Zapf Dingbats

⚠️ any other font families may not print correctly because the computed Postscript font name may be incorrect or not exist on the printer. not me warning you, that’s just the facts 💀

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🦋 DATA STRUCTURES 🦋

the Tk_FontMetrics data structure is used by Tk_GetFontMetrics to return information about a font and is defined as follows:

              typedef struct {
                  int ascent;
                  int descent;
                  int linespace;
              } Tk_FontMetrics;

the ascent field is the amount in pixels that the tallest letter sticks up above the baseline, plus any extra blank space added by the designer of the font.

the descent is the largest amount in pixels that any letter sticks below the baseline, plus any extra blank space added by the designer of the font.

the linespace is the sum of the ascent and descent. it’s how far apart two lines of text in the same font should be placed so that none of the characters in one line overlap any of the characters in the other line. periodt.

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🔥 SEE ALSO 🔥

• font(n)
• MeasureChar(3)

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👑 KEYWORDS 👑

• font
• measurement
• Postscript

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okay that’s the whole iconic page — brought to you by Tk 8.0 and the Tk_FontId(3) manual page 💖✨