Benchmarks
Kamali Suite against ONLYOFFICE and Apryse, with the same fonts
Comparing renderers only means something when they draw with the same fonts. Here's what happened when I gave them all exactly the same files.
Now that I have a way to score a renderer against Office, the obvious next question was: how do the others do? I picked two that people actually use for Office files in the browser or on a server: ONLYOFFICE and Apryse.
My first comparison was unfair
The first time I ran ONLYOFFICE, it looked terrible. Then I found out why. Its converter runs as its own user, and the Aptos font files I had copied in were only readable by root. So it silently drew everything in Arial.
That wasn't a rendering gap, it was a file permission. Since fixing it, the rule is strict: every engine gets exactly the same font files, including the Windows fonts real documents ask for. Any difference left is the engine.
Whole pages
Same fonts, same files, same scoring against Office's own PDFs:
| Set | ONLYOFFICE | Kamali Suite | Gap |
|---|---|---|---|
| Word, test corpus | 71.7 | 84.0 | +12.3 |
| PowerPoint, test corpus | 80.3 | 90.5 | +10.2 |
| Word, second set | 69.4 | 91.5 | +22.1 |
| PowerPoint, second set | 77.4 | 95.2 | +17.8 |
On Excel the gap is over 70 points, but that says more about how ONLYOFFICE paginates spreadsheets into PDF than about how it draws them.
SmartArt
SmartArt is a good stress test, because a file can carry two things: the diagram's data, and a saved drawing of it that Office made. An engine can cheat by just showing the saved drawing. So I tested both ways on 755 SmartArt diagrams from Word documents.
With the saved drawing removed, so the engine has to do the layout itself:
- Kamali Suite came out 0.4% off.
- ONLYOFFICE left 260 of 755 diagrams blank, layouts it doesn't know.
- Apryse drew nothing at all. All 755 empty.
With the saved drawing left in, everyone does better, and the ranking stays the same.
Where ONLYOFFICE wins
It's not a clean sweep. On the ten SmartArt diagrams where I'm weakest, with real fonts everywhere, I was closer to Office on six, ONLYOFFICE on three, and one was even. Its ring layouts (Text Cycle, Radial Cycle with many items) are better than mine right now. They're on my list.
Why I'm publishing this
Not to dunk on anyone. These are hard problems and both products do a lot. But "looks like Office" is a claim everyone makes, and the only way to make it mean something is a ruler, the same conditions for everyone, and numbers you can check.