Cantor 26.4 - KTextEditor, New LaTeX Rendering and more

The KDE community recently announced the release of KDE Gear 26.4, which includes a new version of Cantor. As KDE's front end for scientific interactive computing, Cantor has taken a significant step forward with this release.

During this development cycle, our focus was primarily on modernising core components, improving reliability and optimising daily workflows. In this post, we will highlight the most significant improvements in Cantor 26.4.

A Modern Editing Experience with KTextEditor

The most significant change in this release is the integration of the KDE KTextEditor framework. This replaces Cantor’s previous custom text editing and syntax highlighting code, which had become difficult to maintain, especially given the multiple systems and languages that Cantor supports. Some of the previous limitations in this area were difficult to resolve, so after lengthy internal discussions, the team decided to abandon the custom code developed over several years and switch to a more reliable, feature-rich framework. This framework also powers KDE's advanced text editor, Kate, and is used in other applications, such as LabPlot, for its internal scripting editor.

You can now enjoy a more powerful editing experience in Cantor's worksheet. Features such as multi-line editing, bracket matching and code folding and indentation are available straight away, and syntax highlighting is consistent across all backends and automatically adapts to the system theme. With this change, we have also added support for theming in general, enabling users to switch between different themes and customise the appearance of the worksheet. Below screenshot shows two different Cantor themes:

Improved variable handling

Cantor's variable manager provides an overview of all the variables that the user has created in the current session. In this release, we have unified the underlying infrastructure to handle variables for different languages. The new editor uses the unified variable model to provide real-time, cross-backend autocompletion. As with the switch to KTextEditor mentioned above, this transition is not just about new features, but also about establishing a more maintainable and future-proof foundation on which we can build.

Reworked LaTeX Rendering Pipeline

In version 26.4, we completely redesigned the LaTeX rendering pipeline.

Thanks to the modernised 'pdflatex → PDF' pipeline driven by Poppler, the new pipeline provides faster and more reliable rendering results. It replaces the previous EPS-based workflow and simplifies the overall architecture.

Equally importantly, this change removes the long-standing dependency on libspectre, thereby eliminating a number of crashes reported in this library on certain Linux distributions. LaTeX preview is now a stable and reliable feature. Any existing projects that used EPS are automatically re-rendered as PDFs when opened, ensuring full compatibility with previous work.

Continuous Improvements

As with previous releases, our focus was on bug fixing and making various smaller improvements to the codebase, as well as the major updates and refactoring described above. One example is that we fixed Maxima's terminal error handling to support redirection of error output to the standard error stream (stderr) in version 5.48 and later.

These efforts contribute together to improved stability, performance and overall refinement, and we have more new ideas and projects for Cantor in the pipeline. Stay tuned!