It’s been a while since we last shared a major update of Graphs. We’ve had a few minor releases, but the last time we had a substantial feature update was over two years ago.

This does not mean that development has stalled, to the contrary. But we’ve been working hard on some major changes that took some time to get completely right. Now after a long development cycle, we’re finally getting close enough to a release to be able to announce an official beta period. In this blog, I’ll try to summarize most of the changes in this release.

New data types

In previous version of Graphs, all data types are treated equally. This means that an equation is actually just regular data that is generated when loading. Which is fine, but it also means that the span of the equation is limited, the equation cannot be changed afterward, and operations on the equation will not be reflected in the equation name. In Graphs 2.0, we have three distinct data types: Datasets, Generated Datasets and Equations.

Datasets are the regular, imported data that you all know and love. Nothing really has changed here. Generated Datasets are essentially the same as regular datasets, but the difference is that these datasets are generated from an equation. They work the same as regular datasets, but for generated datasets you can change the equation, step size and the limits after creating the item. Finally, the major new addition is the concept of equations. As the name implies, equations are generated based on an equation you enter, but they span an infinite range. Furthermore, operations you perform on equations are done analytically. Meaning if you translate the equation `y = 2x + 3` with 3 in the y-direction, it will change to `y = 2x + 6`. If you perform a derivative, the equation will change to `y = 2x` etcetera. This is a long-requested feature, and has been made possible thanks to the magic of sympy and some trickery on the canvas. Below, there’s a video that demonstrates these three data types.

Revamped Style Editor

We have redesigned the style editor, where we now show a live preview of the edited styles. This has been a pain point in the past, when you edit styles you cannot see how it actually affects the canvas. Now the style editor immediately tells you how it will affect a canvas, making it much easier to change the style exactly to your preferences.

We have also added the ability to import styles. Since Graphs styles are based on matplotlib styles, most features from a matplotlib style generally work. Similarly, you can now export your styles as well making it easier to share your style or simply to send it to a different machine. Finally, the style editor can be opened independently of Graphs. By opening a Graphs style from your file explorer, you can change the style without having to open Graphs.

We also added some new options, such as the ability to style the new error bars. But also the option to draw tick labels (so the values) on all axes that have ticks.

The revamped style editor

Improved data import

We have completely reworked the way data is imported. Under the hood, our modules are completely modular making it possible to add new parsers without having to mess with the code. Thanks to this rework, we have added support for spreadsheets (LibreOffice .ods and Microsoft Office .xlxs) and for sqlite databases files. The UI automatically updates accordingly. For example for spreadsheets, columns are imported by the column name (alphabetical letter) instead of an index, while sqlite imports show the tables present in the database.

The new import dialog

Furthermore, the import dialog has been improved. It is not possible to add multiple files at once, or import multiple datasets from the same file. Settings can be adjusted for each dataset individually. And you can even import just from a single column. We also added the ability to import error-bars on either axes, and added some pop-up buttons that explain certain settings.

Error bars

I mentioned this in the previous paragraph, but as it’s a feature that’s been requested multiple times I thought it’d be good to state this explicitly as well. We now added support for error bars. Error bars can easily be set on the import dialog, and turned on and off for each axis when editing the item.

Reworked Curve fitting

The curve fitting has been reworked completely under the hood. While the changes may not be that obvious as a user, the code has basically been completely replaced. The most important change is that the confidence band is now calculated completely correctly using the delta-method. Previously a naive approach was used where the limits were calculated using the standard deviation each parameter. This does not hold up well in most cases though. The parameter values that are given are also no longer rounded in the new equation names (e.g. 421302 used to be rounded to 421000). More useful error messages are provided when things go wrong, custom equations now have an apply button which improves smoothness when entering new equations, the root mean squared error is added as a second goodness-of-fit measure, you can now check out the residuals of your fit. The residuals can be useful to check if your fit is physically correct. A good fit will show residuals scattered randomly around zero with no visible pattern. A systematic pattern in the residuals, such as a curve or a trend suggests that the chosen model may not be appropriate for the data.

The old version of Graphs with the naive calculation of the confidence band The new version of Graphs with the proper calculation of the confidence band.

UI changes

We’ve tweaked the UI a bit all over the place. But one particular change that is worth to highlight, is that we have moved the item and figure settings to the sidebar. The reason for this, is that the settings are typically used to affect the canvas so you don’t want to lose sight of how your setting affects the canvas while you’re updating. For example, when setting the axes limits, you want to see how your graph looks with the new limit, having a window obstructing the view does not help.

Another nice addition is that you can now simply click on a part of the canvas, such as the limits, and it will immediately bring you to the figure settings with the relevant field highlighted. See video below.

Mobile screen support

With the upcoming release, we finally have full support for mobile devices. See here a quick demonstration on an old OnePlus 6:

https://cdn.masto.host/floss/media_attachments/files/115/731/446/400/973/237/original/036012181a618059.mp4

Figure exporting

One nice addition is the improved figure export. Instead of simply taking the same canvas as you see on the screen, you can now explicitly set a certain resolution. This is vital if you have a lot of figures in the same work, or need to publish your figures in academic journals, and you need consistency both in size and in font sizes. Of course, you can still use the previous setting and have the same size as in the application.

The new export figure dialog

More quality of life changes

The above are just a highlight of some major feature updates. But there’s a large amount of features that we added. Here’s a rapid-fire list of other niceties that we added:

• • Multiple instances of Graphs can now be open at the same time
  • Data can now be imported by drag-and-drop
  • The subtitle finally shows the full file path, even in the isolated Flatpak
  • Custom transformations have gotten more powerful with the addition of new variables to use
  • Graphs now inhibits the session when unsaved data is still open
  • Added support for base-2 logarithmic scaling
  • Warnings are now displayed when trying to open a project from a beta version

And a whole bunch of bug-fixes, under-the-hood changes, and probably some features I have forgotten about. Overall, it’s our biggest update yet by far, and I am excited to finally be able to share the update soon.

As always, thanks to everyone who has been involved in this version. Graphs is not a one-person project. The bulk of the maintenance is done by me and Christoph, the other maintainer. And of course, we should thank the entire community. Both within GNOME projects (such as help from the design team, and the translation team), as well as outsiders that come with feedback, report or plain suggestions.

Getting the beta

This release is still in beta while we are ironing out the final issues. The expected release date is somewhere in the second week of may. In the meantime, feel free to test the beta. We are very happy for any feedback, especially in this period!

You can get the beta directly from flathub. First you need to add the flathub beta remote:

flatpak remote-add --if-not-exists flathub-beta https://flathub.org/beta-repo/flathub-beta.flatpakrepo


Then, you can install the application:
flatpak install flathub-beta se.sjoerd.Graphs


To run the beta version by default, the following command can be used:

sudo flatpak make-current se.sjoerd.Graphs beta


Note that the sudo is neccesary here, as it sets the current branch on the system level. To install this on a per-user basis, the flag –user can be used in the previous commands. To switch back to the stable version simply run the above command replacing beta with stable.

The beta branch on update should get updated somewhat regularly. If you don’t feel like using the flathub-beta remote, or want the latest build. You can also get the release from the GitLab page , and build it in GNOME Builder.