topola/INSTALL.md

Installing Topola

Building and installing Topola from source

Prerequisites

Building Topola from source requires git and cargo to be installed on your system. Follow the instructions in the above links to obtain these.

Obtaining the source

Clone the repository:

git clone https://codeberg.org/topola/topola.git

Preparing to build

Change your working directory to your clone of Topola's repository:

cd topola

Command-line application

Topola has a command-line application written the help of the clap library.

(If you do not want to install new software on your system, skip now to the Debug build subsection.)

Run the following command to build and install the Topola's command-line application:

cargo install --locked --path crates/topola-cli

You can then invoke the application from your terminal as topola.

Debug build

If you do not want to install new software on your system, or are interested in debugging or developing Topola, you can build a debug executable of the Topola's command-line application inside your working directory by running

cargo build -p topola-cli

Once built, you can invoke the debug executable by replacing the topola command with cargo run -p topola-cli -- .

Autorouting example

As an example, running the following commands will autoroute a KiCad project of a simple THT diode bridge rectifier:

cd tests/single_layer/tht_diode_bridge_rectifier/
topola tht_diode_bridge_rectifier.dsn

(Obviously, to use the debug executable, replace the second command with cargo run -p topola-cli -- tht_diode_bridge_rectifier.dsn.)

By default, the output filename is the input filename with extension changed to ses: tht_diode_bridge_rectifier.ses.

Viewing the results

You can view the results of the autorouting in KiCad if you have it installed. First, open the layout in the KiCad PCB Editor:

pcbnew tht_diode_bridge_rectifier.kicad_pcb

Then choose File > Import > Specctra Session... from the menu bar. In the newly opened file dialog, choose the file named tht_diode_bridge_rectifier.ses. This will load the autorouted traces.

Egui graphical user interface application

Topola has a graphical user interface (GUI) application written using the [egui] (https://github.com/emilk/egui/) library and its paired [eframe](https:// github.com/emilk/egui/tree/master/crates/eframe) framework.

(If you do not want to install new software on your system, skip now to the Debug build subsection.)

The following command will build and install the Topola's GUI application:

cargo install --locked --path crates/topola-egui

You can then start the application from your terminal by running

topola-egui

Debug build

If you do not want to install new software on your system, or are interested in debugging or developing Topola, you can build a debug executable of the Topola's GUI application inside your working directory by running

cargo build -p topola-egui

Once built, you can start the application from the debug executable with the following command:

cargo run -p topola-egui

Native run-time dependencies

On Linux and BSDs, the egui depends on the native graphics libraries (X11, Wayland), and requires GNOME zenity when using xdg-portal (which is the default) as the backend for rfd (which we use for file chooser dialogs).

If the Topola GUI crashes on startup (no window is shown), necessary graphics libraries (X11, Wayland) might be missing. Note that running ldd on the topola-egui executable doesn't show these, they are loaded dynamically (via some dlopen-like mechanism) on startup.

If no file chooser dialog is shown (e.g. when trying to Open a DSN file), and, if topola-egui is started from a terminal, an error message like:

[2025-01-01T01:16:17Z ERROR rfd::backend::xdg_desktop_portal] pick_file error No such file or directory (os error 2)

is emitted (which should only happen on Linux/BSDs and similar environments), then GNOME zenity is not installed, but is required for the file choser to work. Alternatively, one might try the alternative gtk3 backend for rfd by enabling the gtk3 feature of topola-egui, e.g.

cargo build -p topola-egui --release --no-default-features --features disable_contracts --features gtk3

This is mostly interesting for people who want to package Topola, and allow exposing features (e.g. Gentoo Linux / Portage)

Running Topola in Web browser

Topola's GUI application can be built to and run in a Web browser using Trunk. If you have cargo-binstall on your system, you can install Trunk from binary with

cargo binstall trunk

Alternatively, you can build Trunk from source by running

cargo install trunk

To build and open Topola in your browser, run

trunk serve

This will work both with and without having the GUI application installed.

Automated tests

Topola has automated tests to make sure its basic functionalities work. To execute these, run

cargo test

Automated tests are run in debug profile.

Contracts

(The feature described in this section is enabled only when using nightly Rust and only under debug profile. If you are not interested in debugging, you can skip this section altogether.)

When trying to locate the source of a bug, it may be helpful to enable contracts (yes, this Wikipedia article needs improvement), which are nothing else but somewhat enchanced assertions.

Unfortunately, the contracts library which we have been using enforces post-conditions via closures, which have deal-breaking limitations. To bypass these we have forked and modified it to use try blocks instead. The fork is vendored in the vendored/contracts/ directory.

However, try blocks are not present in stable Rust yet, so to use these you need to set up your toolchain to use a nightly version of Rust.

Nightly Rust

To use nightly Rust, run the following command:

rustup override set nightly

You can go back to stable with

rustup override unset

Enabling contracts

To enable contracts, simply add a --no-default-features switch. This switches off a default feature that prevents contracts from executing. For example, to build tests with contracts, simply run

cargo test --no-default-features

Of course, you can enable contracts for any build target. For instance, the following command will build the Egui application with debug profile and contracts enabled:

cargo build -p topola-egui --no-default-features