load_bitmap_font(3alleg4)

💖 load_bitmap_font — the "steal a whole font out of a picture" page 💖

okay bestie, so this is a page from the Allegro manual — Allegro being the game programming library, the classic one, the legend, the blueprint. And this specific function? She's a font extractor. That's the vibe. Let's get into it 🦋

✨ NAME ✨

load_bitmap_font — grabs a font from a bitmap file. Part of the Allegro game programming library. That's the whole job description, and honestly? She ate. 💅

✨ SYNOPSIS ✨

#include <allegro.h>

FONT *load_bitmap_font(const char *filename, RGB *pal, void *param)

look at her. three params, one pointer out. iconic. 👑

✨ DESCRIPTION ✨

So here's the tea, bestie: this function tries to grab a font from a bitmap. And the bitmap can be in any format that load_bitmap understands — so you're not locked into one file type, go off, use whatever you've got. 🌈

Now, the way it figures out how big each character is? It doesn't ask you. It reads the layout of the image itself. The image needs to be a rectangular grid containing all the ASCII characters from space (32) all the way up to the tilde (126). Yes, the whole lineup. No stragglers. 🎀

And the way the characters are separated depends on the color depth of the image file — this is the part where you have to pay attention, because the rules are different depending on which one you're in:

• paletted (8 bit) image file — use color 0 for the transparent portions of the characters, and fill the spaces between each letter with color 255.
• High (15/16 bit) and true (24/32 bit) color image file — use bright pink (maximum red and blue, zero green) for the transparent portions of the characters, and fill the spaces between each letter with bright yellow (maximum red and green, zero blue).

⚠️ Also note: in each horizontal row, the bounding boxes around the characters should align and have the same height. Don't be chaotic about it. The grid has to be a grid, fr fr.

Probably the easiest way to get to grips with how this works is to load up the demo.dat file and export the TITLE_FONT into a PCX file. Then open up the resulting picture in your paint program — that is the format a font should be in. Literally just look at it. That's the whole tutorial. Study it like it's your final exam. 📚✨

Now the serious bit, bestie, and I need you to lock in 🔒 — take care with high and true color fonts: Allegro will convert these to the current color depth when you load the font. And if you then try to use a font on a bitmap with a different color depth, Allegro will do color conversions on the fly, which will be rather slow. Not cute. Not the move. For optimal performance you should set the color depth to the color depth you want to use before loading any fonts. Order of operations matters, periodt. 💀

✨ RETURN VALUE ✨

Returns a pointer to the font, or NULL on error. 🙈

And remember — you are responsible for destroying the font when you are finished with it, to avoid memory leaks. Nobody's gonna clean up after you. That's your font, your responsibility, your main character arc. 🫶

✨ SEE ALSO ✨

• register_font_file_type(3alleg4)
• load_font(3alleg4)
• load_bitmap(3alleg4)
• set_color_depth(3alleg4)
• grab_font_from_bitmap(3alleg4)

go read those too, bestie, they're all in the same little friend group 💜

Allegro, version 4.4.3 — and this page is load_bitmap_font(3alleg4). That's the source, that's the version, that's the date stamp, and that's the whole page. mwah 💋 slay, go make some fonts, ily 🦋✨