This was a programming test for a contracting position for Inkscape. Applicants have permission to post their submissions now that the deadline has passed.

Some notes on my submission: I decided to go with a comprehensive interpretation of the task - namely, that in order to ignore all undesired commands, they must be properly parsed. Most can be parsed generically, but a few of them have special parsing rules. This is explained in code comments.

See the changelog to see which parts are mine. It includes filling out hpgl_input.py as well as creating a couple test files.

What follows is the original text of the assigmnent:

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Programming test for the Inkscape Python Developer contract role (2023 Q1)

This repository contains the instructions to perform the programming test of the role that the Inkscape project is currently looking to fill.

Note that this is not the file format that will be implemented during the contract. The HPGL file format is already supported by Inkscape - the code submitted by the candidates will be used solely for the purpose of selecting the candidates, so no worries that we freeboot your work!

This readme contains:

• the task instructions,
• instructions how to run the provided unit tests.

This repository provides the following starting points:

• boilerplate code for an Inkscape import extension for HPGL files
• unit test files,
• and the unit tests themselves.

Task description

Your task is to implement two commands from the HP-GL plotter language. The user guide of this language is given here: http://www.hp.com/ctg/Manual/bpl13211.pdf

The general syntax of HPGL files is provided on page 9-10. The two commands that should be supported are PD (page 123) and PU (page 138), which is sufficient to read simple line diagrams. All other commands should be ignored by the parser.

The unit tests evaluate all paths in the output file together; it does not matter whether paths are split into subpaths (i.e. after each PU command) or not. The style of the path must contain a black stroke and a non-zero stroke width, and fill must be set to none. The coordinate transformation between HPGL plotter units (plu) and SVG units is handled by the parent layer that already exists in the boilerplate code; your paths may directly copy the coordinates of the HPGL file.

For example, the HPGL string

IN; SP1; PU 10,10; PD 10, 30; PU 20, 30 PD 20, 10, 10, 10;

translates to

M 10 10 L 10 30 M 20 30 L 20 10 L 10 10

or equivalently (a lot of options are possible and valid, the unit test only checks that the node positions match)

m 10 10 v 20 m 10 0 v -20 h -10

which renders as a "u" shaped path.

It is strongly recommended to use pyparsing>=3.0.0 (or another parsing library that you're comfortable with) for this assignment, even though it might seem overkill for this simple problem - but it shows us that you can work with parsing libraries.

The boilerplate code uses Inkscape's python library inkex (https://inkscape.gitlab.io/extensions/documentation/). The library will be needed to create and append PathElements to the document, setting the style and path data, and raising an error if the provided file is invalid.

Deadline

The assignment must be submitted by Jan 23, 23:59 UTC.

Unit tests / Development setup

1. Please create a private fork of this repository and clone it.
2. Install inkex from sources (e.g. in a virtualenv)
   pip install 'inkex @ git+https://gitlab.com/inkscape/extensions@master' . On Windows, you might need to increase the file name length limit of git: git config --system core.longpaths true.
3. Run pytest in the repository's root folder. The dummy tests (which test the testing mechanism) will succeed, but the actual unit test in test_paths.py will fail. Your task is to change the code in hpgl_input/hpgl_input.py (marked by TODO) such that the test will pass.
4. (Not required) - you can symlink the local clone into ~/.config/inkscape/extensions (or %AppData%\Inkscape\extensions) in order to get your extension to work with Inkscape. Then, create a file with the extension .plt - for example, the sample file in tests (which is a modified version of https://github.com/spustlik/plotr/blob/master/Plotr/Samples/space-COLUMBIA.hpgl), and open it with Inkscape.

Submission

Please invite Gitlab user @joneuhauser into your private fork with Reporter access permissions.

Respond to the email that you received from the Hiring team by providing the link to your repository as well as the commit hash that contains your submission.

(You are free to publish your solution after the deadline (under MIT license), but please refrain from doing so until then. For this reason, no LICENSE file is included in this repo.)

Evaluation criteria

• Your code must pass the provided unit tests. If any unit tests fail, please explain these failures along with your submission via email. If you feel like there's a mistake in the task, please communicate this early.
• Your code should be adequately documented.
• Use a consistent coding style. Use of an automated code formatting tool is encouraged.
• The history of the submitted commit hash should be clean; and the commit messages should adhere to standard practice.