buchstabensuppe
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at least better than PIL.ImageFont
toy font rendering for low pixelcount high contrast displays, i. e. openlab's flipdot display.
features
- supports text shaping via harfbuzz
- per grapheme cluster font fallback
- grayscale and binary b/w support
building
requirements:
- redo-c
- Optionally
makefor install script and such - utf8proc
- harfbuzz
- libschrift == 0.10.1
# run inside nix-shell if you have nix! # static library $ redo libbuchstabensuppe.a # demo binary $ redo bs-renderflipdot.exe # tests $ redo test.exe && ./test.exe
alternatively you can just run nix-build
demo
if you want to play around with the font rendering in binary
mode you can use the dry run mode of the supplied ./bs-renderflipdot.exe
(or ./result/bin/bs-renderflipdot if you use nix) binary.
Run ./bs-renderflipdot.exe -? for usage instructions and don't forget -n
for dry running!
$ ./bs-renderflipdot.exe -f fonts/unifont.ttf -f fonts/unifont_upper.ttf -n "Greetings ❣️" 2>/dev/null ███ ███ █████████ █ █████████ ████ █ █ █████████ █ █ █ █ ███████ █ █ █ ███ ████ ████ █ ██ █ ███ ███ █ ████ ███ █ ██ █ █ █ █ █ █████ █ ██ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ███ █ ██████ ██████ █ █ █ █ █ █ ██ ███ █ █ █ █ █ █ █ █ █ ███ ██ █████ █ █ █ █ █ █ █ █ █ █ █ █████ █ ██ █ █ █ █ █ █ █ █ █ ████ █ █ █████ ███ █ █ ████ ████ ██ █████ █ █ █ █ ████ ███ █ █ ████
flipdot interaction
the picture above shows buchstabensuppe being used to render text onto a simulated flipdot display. take notice especially of the following:
- fallback fonts are supported: the emoji is not found in
unifont.ttf, but rendered fromunifont_upper.ttf - correct text shaping is supported (as far as the font supports it): g̈ which consists of two codepoints is rendered as a combined cluster consisting of two glyphs.
bs-renderflipdot.c is a simple example showing how to interact with a flipdot display. mainly it involves:
- rendering a string to a bitmap using
bs_render_utf8_string - making sure that the dimensions of the display and the image
match with
bs_bitmap_extend - processing the resulting bitmap using
bs_bitmap_map - rendering the resulting bitmap on the display using
bs_flipdot_render. - dealing with bitmaps too big for the display using
bs_scroll_next_viewandbs_page_next_view.
you can also play around with its cli: the following command
renders “Hello World” black on white using GNU Unifont onto
a flipdot display (or simulator) running on localhost:2323.
See bs-renderflipdot(1)
for more usage details.
./bs-renderflipdot.exe -f /path/to/unifont.ttf -f /path/to/unifont_upper.ttf -i "Hello World"
caveats
- buchstabensuppe loads all fonts into memory and keeps them there pretty much all the time.
- there is no support for right to left nor vertical script (but planned)