Time For Apple To Reboot CoreText? (U)

John Gruber says titles with question marks are bullshit but I’m going to ask the bullshit question anyway. Is it time for Apple to reboot CoreText? There is never a good time to replace a text layout rendering engine, but it’s always a good time to build a strong robust one.

CoreText is usually a dead Twitter topic but with the latest iMessage text/CoreText bug, coming right after the previously fixed one, there’s suddenly lots of complaining. In many ways this is just the tip of the iceberg.

The history of CoreText is convoluted to say the least. It’s a victim of Apple’s OS odyssey: the revolutionary QuickDraw GX roadmap of Classic MacOS, the attempt to sweep the good GX bits into OS X ATSUI, then sweeping those good bits in the modern 64-bit CoreText rewrite. Unfortunately many advanced typography GX features were scattered in the process and Apple’s half-assed text / font engineering resource allocation since the end of the GX era is now biting everybody in the ass. The long-term piecemeal approach is falling apart.

On top of this we now have the OpenType Variable Fonts built on the TrueType GX model. CoreText does all the rendering so “it just works” like TrueType GX always has but what is its place on iOS and what’s the angle for end users? Don’t worry, Google hasn’t figured it out either.

And then there is this little Twitter thread which has fascinated me for months.CoreText End

I have heard similar architectural criticism of CoreText from Japanese developers over the years such as the font engineers at Morisawa and Norihito Hirose of MONOKAKIDO who has seen and coded it all since the GX days and is busy wrangling with CoreText as he reboots the highly regarded egword Universal 2 Japanese word processing app.

With this latest iMessage mess I think we have an answer: it is time for a new text rendering engine for the modern mobile era of Apple A series CPU/GPU. Think Metal CoreText that off loads text rendering from the CPU with all the great but scattered advanced typography stuff from the GX days pulled into a single fully modernized, bulletproofed with integrated low level + high level frameworks across all Apple platforms. Oh, and ample engineering resources to support it all.

Apple created the modern computer era of advanced typography, Apple platforms deserve the very best text technology and advanced text layout engine. Unfortunately the days of new grand text rendering architectures have been over since the QuickDraw GX era. I don’t see it returning.

I sincerely hope I am wrong.

Update 2/20/2018: edited links and some text for clarity.