For a very long time I’ve been considering contributing to open source financially not just with code contributions. The model I was originally working on was one where I’d “buy” the free-as-in-beer open source software that I was using regularly. Looking at my software stack it’s almost all projects which don’t necessarily have huge corporate backing. Yes I use GitHub but that’s essentially Microsoft at this point. Yes I use Java but that foundation has huge corporate sponsors. Yes I use Linux which has lots of sponsors for some pieces but the projects I use are the smaller off to the side ones. So how did my “buy the software” model work? It turns out that plan sucks.

Between the months of July and August I had a month of travel. Part of that was a three week trip to southern Europe and another week at my first astrodynamics conference in a very long time (the AIAA/AAS Astrodynamics Specialists Conferenec ). Because of that I actually forgot to post some of the things that I had been up to for the first half of July, before my trip. I’m therefore combining my open source contributions update to cover both months in one post. One of the biggest shifts you’ll see is my focus for the time being. While I spent much of May and June focusing on Avalonia or development using it my focus in the past couple months, and for the time being, is shifting to a project called B612 Foundation which is a non-profit organization looking to make strides in improving our ability to track near-Earth asteroids and give us enough warning time to mitigate a potential impact if one is predicted to occur. The work I’m doing on their open source astrodynamics engine and related tools is the perfect merger of my interests and technical capabilites: software engineering and aerospace engineering.

Back in June on a lark, or maybe it was some nostalgia kick induced by an article I read somewhere, I wanted to see if SETI@Home . This was a system designed by UC Berkley around 2000 to turn spare CPU cycles on otherwise idle computers into a massive distributed computing infrastructure. It turns out that not only does it still exist but in the nearly 20 years I hadn’t been paying attention it turned into a giant ecosystem of so-called “Volunteer Computing” (VC) called Berkeley Open Infrastructure for Network Computing (BOINC) .

It’s been awhile since I’ve done development around Diaspora regularly, or anything associated with the API. When I saw the announcement of the work being done with the API at their Hackathon back in April I was pretty stoked. It looks like it will be on track for the 0.8.0.0 release which hopefully will be in the near future. I was especially excited to see that there is a possibility of someone putting it up on a live-test server to work with. To get ready for that I wanted to make sure that my two code bases, the “test harness” and the “Comment Reflector” that used it to create comments for a blog as described in this blog post , worked as soon as a server went live with the code.

I follow a lot of open source developer blogs, including some from project-based blog aggregators like Debian, Ubuntu, and some .NET developers. One of the things they do that I like is that they provide a monthly summary of the open source contributions. In some cases I’m pretty sure it’s part of accountability for getting some funding to work on the project. In other cases I think it’s just a little historical tracking on their part. Some people make lots of changes and others just have one small package they incremented slightly. As I (hopefully) continue to ramp up my open source software contributions I want to begin that process as well. Some of these are relatively inconsequential things. Many of them are documentation-driven. All of them however I hope will help open source projects or users of open source projects in at least some infinitesimal way. Worst case I’m just publically documenting my own experiences to make for easy reference for myself as well as potentially othersThis will be the first such summary articles.

As I get ready to do a tutorial on a live simulator rendering using nothing but Avalonia it looked like using the standard event handlers in .NET and ReactiveUI that are the underpinning of Avalonia data flow would be the easiest way. There is a great example of this too with Nikita Tsukanov’s Avalonia BattleCity Game Demo which I was going to crib off. The first thing that came to mind though was what exactly is the throughput and overhead of .NET’s event handling system. Coming from Microsoft and with it being the core of many patterns not just the UI, but the UI is where we most often prominently see it, I was curious if it would break with large number of objects or handles. I didn’t expect it to be a slouch but exactly how far can it be pushed? This has most certainly done by others and probably even more thoroughly but this is new to me and I found it instructive. This is a write up of my exploration of this and the results.

Tree Views are a standard control for looking at hierarchal data in a user interface. Avalonia has a TreeView Control as well. In this tutorial we are going to go over creating a TreeView control for a league roster system. This is based on a similar tutorial written for WPF by Mike Hillberg that you can find here except that we are skipping the manual list aspects of it. As an FYI, I’m doing my work in JetBrain’s Rider IDE so screenshots and instructions will be from there but this obviously works with any editor. You can find the final solution for this blog post in this Gitlab Repository .

NOTE: This article is from 2019 and Avalonia has been under active development and improvement since that time. Please consult newer tutorials and documentation for how to use this against current releases of Avalonia.

A common way for displaying and manipulating tabular data is some sort of spreadsheet like area which is often called a data grid. In Avalonia that control is literally DataGrid . Starting with a standard project it’s relatively easy to get started however there are a couple of important steps that can be easy to overlook. We are going to go through starting from the default template all the way through to having an application that allows one to edit a data grid. You can find the final solution for this blog post in this Gitlab Repository .

NOTE This article is from 2019 and the DatGrid implementation has changed quite a lot in recent versions. This therefore does not work against recent versions of Avalonia. Please consult newer tutorials and documentation for how to use this against current releases of Avalonia.

There are many ways to lay out UI elements in Avalania from the StackPanel , which stacks things on top of each other or along side each other, to the Canvas which allows one to specify the exact pixel position of any element. The Canvas may sound like the way one would want to go because it gives the most control but in actuality it’s overl prescriptive. If you notice carefully how most user interfaces work they dynamically resize as windows are resized. They try to maintain a sense of proportionality with the drawing area being given to its window. The rigidness of the pixel-based system is sometimes useful but more often than not the panel type you’ll be wanting to use in Avalonia is the Grid . Here is the Part 1 of a multi-part series on the features of the grid and how to use it. You can find the final solution for this blog post in this Gitlab Repository .

NOTE: This article is from 2019 and Avalonia has been under active development and improvement since that time. Please consult newer tutorials and documentation for how to use this against current releases of Avalonia.

In Avalonia Buttons Multiple Ways I went through a tour of the various ways one can bind buttons to commands and events. I wanted to explore the topic just a little deeper and look at some of the more advanced scenarios of dealing with binding behavior, specifically passing parameters to commands and setting the button’s enabled status based on other data in the View and View Model. Let’s build a little app to show how to do this, but you can find the final solution for this blog post in this Gitlab Repository .:

NOTE: This article is from 2019 and Avalonia has been under active development and improvement since that time. Please consult newer tutorials and documentation for how to use this against current releases of Avalonia.