Ofront on Raspberry Pi OS

By R. S. Doiel, 2021-04-25

This post is about getting Ofront¹ up and running on Raspberry Pi OS². Ofront provides a Oberon-2 to C transpiler as well as a Oberon V4³ development environment. There are additional clever tools like ocat that are helpful working with the differences in text file formats between Oberon System 3, V4 and POSIX. The V4 implementation sits nicely on top of POSIX with minimal compromises that distract from the Oberon experience.

An Initial Impression

I first heard of running Ofront/V4 via the ETH Oberon Mail list⁴. What caught my eye is the reference to running on Raspberry Pi. Prof. Templ provides two flavors of Ofront. One targets the Raspberry Pi OS on ARM hardware the second Linux on i386. The Raspberry Pi OS for Intel is an i386 variant. I downloaded the tar file, unpacked it and immediately ran the “oberon.bash” script provided eager to see a V4 environment. It renders but the fonts rendered terribly slowly. I should have read the documentation first! Prof. Templ provides man pages for the tools that come with Ofront including the oberon application. Reading the man page for oberon quickly addresses the point of slow font rendering. It also discusses how to convert Oberon fonts to X Windows bitmap fonts. If you use the X Window fonts the V4 environment is very snappy. It does require that X Windows knows where to find the fonts used in V4. That is done by appending the V4 converted fonts to the X Window font map. I had installed the Ofront system in my home directory so the command was

xset +fp $HOME/ofront_1.4/fonts

Running “oberon.bash” after that immediately improved things. Since I didn’t need the Oberon fonts outside of V4 I added the xset command to the “oberon.bash” script just before it invokes the oberon command.

Goals in my setup

I had three goals in wanting to play with Ofront and running the V4 Oberon.

1. I wanted to work in an Oberon System environment
2. I need a system meets my vision requirements (e.g. larger font size)
3. I wanted to understand the Linz/V4 variation in Oberon’s evolution

Ofront address all three once you get the X Window side setup correctly.

Setting up Ofront and V4

First we need to boot up a Raspberry Pi OS device (or an i386 Linux with X11). We need to retrieve the software from Joseph Templ’s software-templ.com. Two 1.4 versions are available precompiled. The first is for ARM running Raspberry Pi OS and the second is for generic Linux i386 with X11. I initially tested this on an old laptop where running the i386 version of Raspberry Pi OS.

What we need

The following software is usually already installed on your Raspberry Pi OS.

• curl to download the files⁵
• gunzip to uncompressed the archive file
• tar to unpack the archive file

What we do

1. Download the appropriate tar file
   1. ARM: http://www.software-templ.com/shareware/ofront-1.4_raspbian-Pi3.tar.gz
   2. Intel i386: http://www.software-templ.com/shareware/ofront-1.4_linux-386-3.2.tar.gz
2. Make sure we can read the compressed archive file
3. Gunzip and untar the file

Here’s the commands I used for the Raspberry Pi hardware.

    curl -O http://www.software-templ.com/shareware/ofront-1.4_raspbian-Pi3.tar.gz
    tar ztvf ofront-1.4_raspbian-Pi3.tar.gz
    tar zxvf ofront-1.4_raspbian-Pi3.tar.gz

Here’s the commands I used for Raspberry Pi OS on Intel

    curl -O http://www.software-templ.com/shareware/ofront-1.4_linux-386-3.2.tar.gz
    tar ztvf ofront-1.4_linux-386-3.2.tar.gz
    tar zxvf ofront-1.4_linux-386-3.2.tar.gz

At this point there should be an ofront_1.4 directory where you gunziped and untared the archive file. At this point you can test to make sure everything runs by doing the following (remember the font rendering with be very slow).

    cd ofront_1.4
    ./oberon.bash

You can exit the V4 environment by closing the window or typing System.Quit ~ in an Oberon viewer and middle clicking with your mouse⁶.

The reason the system is so slow is that X is having to write bitmaps a pixel at a time in the window holding our Oberon System. What we want X to do is render an X Window font. Joseph as provided us with the Oberon fonts already converted for X! We just need to let the X Window system know where to look.

What we need

• an editor for editing oberon.bash

What we’ll do

1. Exit the running Oberon System using System.Quit ~ or just close the window
2. Edit oberon.bash to speed up font rendering
3. Try oberon.bash again and see the speed bump

With your favorite editor add the xset line before the oberon command is invoked. My “oberon.bash” looks like this.

#!/bin/bash

if [ -z "$OFRONT_HOME" ]; then
  export OFRONT_HOME=.
  echo "OFRONT_HOME set to ."
fi
export OBERON=.:$OFRONT_HOME/V4_ofront:$OFRONT_HOME/V4:$OFRONT_HOME/fonts
export LD_LIBRARY_PATH=.:$OFRONT_HOME/lib
export PATH=.:$OFRONT_HOME/bin:$PATH
xset +fp $HOME/ofront_1.4/fonts
$OFRONT_HOME/bin/oberon -f ./V4/Big.Map -u 8000 -c $* &

The xset command adds the provided X fonts to X Window. This results in a huge speedup of rendering. I also add the options for using the largest font sizes via a font map file, “V4/Big.Map” and set the display units to 8000. Your vision or monitor may not need this so you want to only add the line to include the X fonts needed by Oberon.

Now re-launch Oberon using the updated “oberon.bash” and see the improvement.

    vi oberon.bash
    ./oberon.bash

You now have a functioning V4 Oberon System to play with and explore.

There are some additional POSIX environment setup you can add to improve the integration with your Linux setup. These are covered in the man pages for the tools that come with Ofront. Additional information is also provided in the Oberon Texts and Tools files in the V4 environment. All are worth reading.

What does this setup provide?

At the point we have V4 available we have a rich development and text environment. One which I feel is conducive to both writing in general and programming specifically. You are running under an adapted Oberon System so there are somethings to consider.

The Oberon V4 file system does support punctuation characters aside from periods and slashes. So when I tried to edit a file with hyphens in the name Oberon assumed the filename stopped at the first hyphens. The Oberon file systems are typically case sensitive so this can be worked around with letter case. Of course I could modify the V4 system to allow for more letters too. That’s the nice thing about having the source code.

The second issue if file format. In Oberon we can embed fonts and coloring and that is treated as normal text. End of line characters are represented as a carriage return. In POSIX environments we have “plain text” without specific font directives and we use a line feed to terminate lines. Fortunately Prof. Templ provided a program called ocat⁷ that makes short work of converting an Oberon text into a POSIX friendly format. On the Oberon side of things it’s also easy because Oberon will treat an ASCII file as a text we only need to convert the line endings and in the Ofront implementation of V4 it handles the differences in line endings behind the scenes.

If you create or store a file in the Oberon environment it’ll become Oberon text. If you need to have a plain text version use ocat. If you only read POSIX files in the Oberon environment then they remain plain text files but V4 takes care of translating the POSIX line ending to ones that are displayed nicely in Oberon.

What to explore next?

Now that we have a fast running V4 system we have some choices for development. Joseph Templ has adapted the display for X and also the file system so the files are visible from the Unix shell. This is a powerful arrangement. This supports both Oberon development and the use of Oberon language for the development of POSIX friendly programs. The Ofront collection provides the ofront an Oberon-2 to C translator, ocl is a tool that will combine ofront with your C compiler and linker to produce programs and libraries for Linux. There is also ocat for converting Oberon texts to POSIX plain text and showdef for showing module definitions. Finally Ofront provides the oberon command so we have an Oberon System available as a development environment.

One thing I recommend exploring is Jospeh Templ’s GitHub repository. The makefile provided with the GitHub version assuming an existing installation of ofront. Since we have one we can compile our own copy from scratch. If you’re running i386 you’ll want to look at V4_ofront/linix386 for Pi hardware take a look at V4_ofront/raspbian.

Here’s how I generated a new version on my Pi hardware.

    git clone https://github.com/jtempl/ofront
    cd ofront/V4_ofront/raspbian
    make
    ./oberon.bash

There is a note in the README of that directory about finding libX11.so but I did not need the symbolic link suggested. Since the font path was previously adjusted for the original version I downloaded from Templ’s website I didn’t need to add the fonts again. If I fork Templ’s version or GitHub I will probably update the “oberon.bash” file included to check to see if the X fonts are available and if not add them via xset. That’s on a someday maybe list, for now I am content exploring the system as is.

Someday, Maybe

Things that come to mind after initial exploration include–

• Figure out how to make Atkinson-Hyperlegible⁸ available to V4
• Replace the X11 integration with SDL 2 integration and run under macOS or Windows
• Exploring porting V4 to run natively Raspberry Pi via Clang cross compilers

Not sure I’ll get the time or have the energy to do these things but they are certainly seem feasible with Ofront as it stands now.