load_bitmap_font(3)

📦 version 4.4.3.1, in fedora 43, fedora 44

💖 load_bitmap_font — Allegro manual, section 3 💖

okay bestie, buckle up, we're getting a font out of a picture 🎀 (this is from the Allegro game programming library, section 3, and yes it's exactly as iconic as it sounds)

✨ NAME ✨

load_bitmap_font — grabs a font from a bitmap file 🖼️✨ (Allegro game programming library, being its usual legendary self)

✨ SYNOPSIS ✨

#include <allegro.h>

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

✨ DESCRIPTION ✨

So the whole vibe is: it tries to grab a font from a bitmap, periodt. The bitmap can be in any format that load_bitmap understands — no gatekeeping, we love that for it. 💅

The size of each character? Determined by the layout of the image, babe. The image should be a rectangular grid holding all the ASCII characters from space (32) up to the tilde (126) — that's the whole squad, nobody left behind. 🫶

Now, how the characters are separated depends on the color depth of the image file, and this is the part where you gotta pay attention:

  • 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. that's it, that's the rule. 🌈
  • 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). yep, pink and yellow are doing the heavy lifting here. 🔥

Also, important: in each horizontal row the bounding boxes around the characters should align and have the same height. no chaotic wobbly letters, we keep it tidy. ✨

ngl, 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 go stare at the resulting picture in your paint program — that is the format a font should be in. it's giving "here's the blueprint, bestie." 🎨

⚠️ 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 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. 🐌 For optimal performance you should set the color depth to the color depth you want to use before loading any fonts. trust, do it in the right order. 😭

✨ 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. not Allegro, not the universe, you. main character responsibility. 👑

✨ SEE ALSO ✨

and that's the whole page, bestie — go forth and load some fonts 💖

this has been load_bitmap_font(3), from the Allegro manual, version 4.4.3 — mwah, slay, bye 👋✨

📦 where this page comes from