Rendering of PDF Images and output PDFs on macOS 11 Big Sur
This article concerns the

This article relates to macOS 11 Big Sur (November 2020)

On release of macOS Big Sur, we discovered a crash with Texpad for documents that include vectored graphics in the form of a PDF image. This crash had shown up briefly during the Big Sur Beta period, and we had traced it to an issue with the Big Sur Beta itself, but then it seemed to have resolved in later Betas. Unfortunately it reoccured on release. Although unlikely, it is possible that this crash may have occurred during the rendering of typeset PDFs.

The issue seems to be due to a memory issue with a new drawing system introduced with Big Sur when drawing PDF graphics. This has affected other apps besides Texpad. Unfortunately the fix is not trivial, so in order to fix this we are taking the following steps.

  • Texpad v1.8.17: Immediately on release of Big Sur we had reports of the crash, and we released Texpad v1.8.17 with a fixed that forced all PDF images to be rasterised during the Typeset process in TexpadTeX. This avoided the Big Sur bug, and stopped the crash completely. However, it had the side effect that the vectored graphics would look pixellated on the output in some cases. This occurs in both in Texpad’s viewer, and in the generated PDF. Apologies if you were affected by this problem, but it was important to stop the crash as soon as possible, and this was the unfortunate consequence of that.
  • Texpad v1.8.18: On Wednesday 18 November, we released Texpad v1.8.18 with an improved fix for the crash that does not cause pixellation. Additionally this fix is more focussed, and will not affect users on Mojave or Catalina. There is a possibility that this version will suffer very slightly degraded performance with Live Typeset compared with Texpad v1.8.16 for those on Big Sur.
  • Texpad v1.8.19 After some further work, we believe that v1.8.19 has a workaround for the Big Sur crash that causes neither the pixellation of v1.8.17, nor the degraded performance of v1.8.18. The longterm fix is the new viewer described below, but until that point this will be the longterm workaround for the Big Sur crash.
  • Long term: Over the summer we have been working on a significant update to Texpad’s internal TexpadTeX typesetter, and its output viewer. Amongst many internal improvements and bug fixes, this update interfaces TeX directly with the graphics card using Apple’s Metal framework for drastically improved performance for all users. Additionally, due to internal changes in how TexpadTeX and the viewer work in this case, it avoids the Big Sur crash entirely. Unfortunately, although it is working well in the development branch, it was not quite ready for release at the time of Big Sur’s release, so we are now working to get this ready for release as we can. As well as stopping the Big Sur graphics crash and any pixellation issues introduced by our fixes, it will provides massive performance improvements for Texpad’s viewer, with quicker Live Typeset than ever before, smoother zooming & scrolling, and a colour grading system so that blends the PDF perfectly with the UI in Dark Mode.

Apologies for any inconvenience that this causes, if you have any questions, please email