FreeType generator & MicroPython FontDrawer

Project contains several items:

FreeType Generator : a Python 3 FreeType Font generator creating font files that are compatible with MicroPython ressources.
FontDrawer : a MicroPython library loading font file and draw font-based text onto graphical display (via FrameBuffer manipulation).

FreeType Generator

The generator project will load .ttf files and generates font files under (.py and .bin) format.

The .bin files could be copied to the MicroPython board and then be used with MicroPython code to draw font-based text.

The .py file are intermediate file that can be used for inspection and better understanding of the the font internals. This file can be loaded into a Python 3 as well as a MicroPython session. This file format imply a big parsing overhead under MicroPython, the raison why we now use binary format!

See the Files section here under for more details about the font file organization, their compilation to python and binary format.

FontDrawer

The font drawer is a MicroPython code that uses a .bin font file to draw characters inside the MicroPython FrameBuffer of a screen.

The binary .bin format is quicly loaded inside the microcontroler memory with minimal impact on the micropython parser!

The fdrawer.py library and desired font (.bin files, EG: vera.m15.bin) must be copied to the MicroPython board.

The following test_basic.py example shows how to draw a character and a string.

from machine import I2C
from SSD1306 import SSD1306_I2C
from fdrawer import FontDrawer


i2c = I2C( 1, freq=2000000 )
lcd = SSD1306_I2C( width=128, height=64, i2c=i2c, addr=0x3c, external_vcc=True )

# Normal FrameBuffer operation
lcd.rect( 0, 0, 128, 64, 1 )
lcd.show()

# Use a font drawer to draw font to FrameBuffer
fd = FontDrawer( frame_buffer=lcd, font_name = 'vera_m15' )
fd.print_str( "Font Demo", 2, 2 )
fd.print_char( "#", 100, 2 )
fd.print_str( fd.font_name, 2, 18 )

# Send the FrameBuffer content to the LCD
lcd.show()

Which produce the following results:

Note:

the "m" in front of "m15" means that the .bin file only contains a part of the character set.
An uncoded character is replaced by a squared rectangle (like the space in this example)

Other examples and dedicated README are availables in the micropython (Font-Drawer) subfolder

Files

ttf-fonts/ : This folder contains source font that will be transformed
upy-fonts/ : This folder contains the microPython font file generated (*.py & *.bin files). Binary file format is described in the tech_info.md .
generate-all-font.sh : Use the ft-generate.py to generates all the ILI9341 inside ili-fonts/ from FreeType font available in ttf-font/
ft-generator.py : script with arguments generating ILI-driver fonts (see the .sh file for sample, please read the ili-fonts.md for more information on applicable naming conventions).
ft-view.py : debugging tool. Allow to view a character bitmap encoding (or the whole font set). calculate the max size (height,width) of the font. The file ft-view-for-vera.txt shows the generated content... which is very interesting to learn.
ft-view-encoded.py : same as ft-view.py but also showing the encoded data (useful for bug tracking)

Somes of the fonts availables in the upy-fonts folder:

arrow_15

arrow_23

dejav_m8

dejav_m10

dejav_m12

dejav_m15

dejav_m20

etypo_13

etypo_23

fserif_m10

fserif_m12

fserif_m15

fserif_m20

heyd_23

pitch_15

pitch_23

robotl_m8

robotl_m10

robotl_m12

robotl_m15

robotl_m20

vera_10

vera_23

veram_15 (VeraMono)

veram_23 (VeraMono)

Install instructions

The font generator "ft-generator.py" is a Python 3 script with some dependencies. You will need to install the dependencies prior to use them.

pip3 install freetype-py
pip3 install docopt

FreeType and library installation on non Linux machines

FreeType library should be available aout-of-the box on most of the Linux systems (As Linux Mint, Ubuntu and Debian).

For windows, you will certainly run into a '''dll nightmare'''. Finding the good DLL version properly compiled for win32/win64 was a lonnnnnnggggg path to go.

Here some path to find the good Windows DLL. Better use Linux!

*** DLL Nightmare on Windows ***

http://www.freetype.org/

Win32 installation can be found here
http://gnuwin32.sourceforge.net/packages/freetype.htm

Resources

Technical details

tech_info.md - describing the binary format for font.

FreeType

DocOpt - argument parser

La plus belle manière de parser les arguments de script en python

docopt.org
La plus belle maniere de parser les arguments de script en python sur Sam-et-Max (attention, gros écarts de langage).

About font

A Crash Course in Typography: The Basics of Type noupe.com
Font Kerning Wikipedia
Glyph Metrics Freetype.org

Roman Podgaiski ILI9341 driver

This project was initially written to support the ILI9341 driver from Roman Podgaiski. Later the project were improved to be used with any FrameBuffer based screen display.

The ILI9341 driver is developed by Roman Podgaiski (ropod7) and is available here at https://github.com/ropod7/pyboard_drive

Some French technical information and wiring are available at MCHobby http://wiki.mchobby.be/index.php?title=MicroPython-ILI9341

mchobby/freetype-generator

FreeType generator & MicroPython FontDrawer