Development

Between January 2022 and March 2026, Ansel landed 297 non-merge commits regarding the lighttable grid, its thumbnails, and their rendering pipeline and caching. I tried to make do with the scruffy Darktable lighttable code, only degreased, for as long as I could but unfortunately, it was pure technical debt and it was painfully slow.

Indeed, Darktable “manages” the crappiness of its lighttable by reducing its size: the left and right side panels take a lot of display surface, which leaves even less area for the lighttable to repaint. Since Ansel removed the right side panel, merging its content with the left one and the global menu, there was more surface to paint, more CPU work to do, and the terrible design of the lighttable became all the more harmful.

Desde que empecé a usar Darktable, allá por 2012, siempre me sorprendió lo poca RAM que usaba. La gente cree que es bueno que una aplicación use la memoria con moderación, y eso es cierto sin duda si hablamos de tu entorno de escritorio. Pero hablando de un software de producción que hace un renderizado intensivo de píxeles sobre imágenes de 12 a 54 Mpíxeles, esto significa que los mismos cálculos pesados se hacen una y otra vez en lugar de guardarse para reutilizarse más tarde. Para eso sirve una caché: para evitar cálculos costosos. Y para eso debería usar toda la RAM disponible, porque calcular es malgastar energía, y eso tiene un impacto concreto si trabajas con batería. Además, pagaste por esa RAM y usarla no vacía tu batería. La CPU/GPU, por otro lado…

Memorias de un tipo que pasó demasiado tiempo limpiando la mierda de los demás y pagando por sus malas decisiones, episodio #demasiados.

Copiar/pegar historiales y estilos son funciones fundamentales en Ansel, y las que hacen que merezca (o no) su título de «aplicación de flujo de trabajo». Pero también están entre las más difíciles de acertar internamente. Los usuarios ven una lista de ediciones, pero por debajo esas ediciones dependen del orden del pipeline, de las instancias de módulos y de las máscaras. Si dos imágenes tienen topologías de pipeline distintas, copiar ediciones de forma ingenua puede producir inconsistencias.

Back in December 2019, I asked that someone took care of providing AppImages packages  for Darktable. The obvious benefit would have been enabling early testing, prior to release, from people who can’t build the source code themselves, as to hopefully provide early feedback and help debugging before releasing. This has never been a priority, which means that it was ok to have a pre-release and a post-release rush to fix bugs.

Ansel inherits from Darktable its database backbone: the non-destructive editing histories are saved per-picture into an SQLite database, along with metadata and other user-defined data. Making the database aware of new pictures is done through “importing” pictures from a disk or a memory card. That’s where the import tool comes.

Unfortunately, the Darktable importer is another thing that was butchered circa 2020 and turned into something deeply disconcerning, as it is a file browser that resembles no previously-known file browser, and manages to lack basic features (like Ctrl+F or EXIF preview) while still being bloated with useless ones (see below). This is where we loose many a future user, and it is only step 0 of the workflow. What a great showcase of what a “workflow app” can do !

I have thought, for a very long time, that there was some kill-switch mechanism on the pixel pipeline. The use case is the following :

1. you are changing a module parameter,
2. the previews (the central darkroom one and the thumbnail in left panel, also used for histogram and color pickers) recompute their pipeline to account for that change,
3. one of the previews finishes rendering before the other, and the result is obviously not what you wanted,
4. you change again the module parameter, without waiting for the recomputation to finish.

In that case, you want to kill all active pipelines because their output will not be used, and start recomputing everything immediately with new parameters. Except Darktable doesn’t do that, it lets the pipeline finish before restarting it, and looking at the comments in the source code, it seems to be a fairly recent regression and not the originally intended behaviour.

Darktable has its own GUI widgets library, for sliders and comboboxes (aka drop-down menus or selection boxes), called Bauhaus (in the source code, it’s in src/bauhaus/bauhaus.c). While they use Gtk as a backend, Bauhaus are custom objects. And like many things in Darktable, custom equals rotten.

In 2022, ‍I noticed parasite redrawings and lags , when using them, leading to a frustrating user experience : the widget redrawing seemed to wait for pipeline recomputations to complete, which meant that users were not really sure their value change was recorded, which could lead them to try again, starting another cycle of expensive recomputation, and effectively freezing their computer for several very frustrating minutes of useless intermediate pipeline recomputations.

I accidentally discovered that the Linux build script used a “package” build, meaning the CPU optimizations are limited to generic ones in order to produce portable binaries that can be installed on any x86-64 platform. By “using”, I mean the package build was not explicitely disabled, so it was enabled by default.

Anyway, this is now disabled by default, since the actual packages (.exe and .appimage) are not built through that script, which is primarily meant to help end-users. To get the previous behaviour back, you would need to run:

2022 was so bad in terms of junk emails and noise that I started the Virtual Secretary , a Python framework to write intelligent email filters by crossing information between several sources to guess what incoming emails are and whether they are important/urgent or not. When I’m talking about junk emails, it’s also Github notifications, pings on pixls.us (thank God I closed my account on that stupid forum), YouTube, and direct emails from people hoping to get some help in private.

It’s been roughly 3 months that I rebranded “R&Darktable” (that nobody seemed to get right), into “Ansel”, then bought the domain name and created the website from scratch with Hugo (I had never programmed in Golang before, but it’s mostly template code).

Then I spent a total 70 h on making the nightly packages builds for Windows and Linux work for continuous delivery, something that Darktable never got right (“you can build yourself, it’s not difficult”), only to see the bug tracker blow up after release (nothing better than chaining the pre-release sprint with a post-release one to reduce your life expectancy).