Extremely low performance in GIMP (gimp2 @2.10.12_2 +quartz, macOS 10.14.6)

[i0ntempest]

GIMP built with +quartz variant is extremely slow when using brushes and opening a second file (when one file is already open). All the dependencies are also built with +quartz if available. This does not happen in the version downloadable on their official website.
I've opened an issue in the GIMP repo (​https://gitlab.gnome.org/GNOME/gimp/issues/4130) but the maintainer told me that this might be related to how GIMP and its dependencies are built, and suggested me to ask here.
Please tell me if I need to provide more info. Thanks!

[i0ntempest]

GIMP devs have confirmed this is a problem within the binary when linking against 10.14 or newer SDKs, and have suggested a temporary solution:

# Temporary fix for linking against macOS SDK >10.13
configure.ldflags-append \
                    -Wl,-sdk_version,10.9

I've tested this on both 10.14 and 10.15. Should I make a PR?

[i0ntempest]

In 7a3fea089dea9014171292a6ec4911902ccea651/macports-ports (master):

gimp2: fix stuttering when linking SDK > 10.13

Since the maintainer didn't respond on trac I'll just open a PR anyway.

Closes: #59481

gimp2: force sdk_version only on 10.10 or newer

gimp2: Change forced SDK version to the latest good one

gimp2: add platform darwin in check before the fix

[Tatsh (Andrew Udvare)]

I am experiencing this issue on Big Sur. Can we re-open this?

[mascguy (Christopher Nielsen)]

For the near-term, your best bet is to install the official binaries from gimp.org. (They finally started providing them for macOS again, at the end of 2020.)

And the latest few have Big Sur fixes. Try this one to start with:

​https://download.gimp.org/mirror/pub/gimp/v2.10/osx/gimp-2.10.22-x86_64-3.dmg

There's still a known issue with the marching ants around selections, but it's apparently much-improved overall. Give it a try, and let us know if it's better.

[mascguy (Christopher Nielsen)]

PR created for update to 2.10.24, which includes upstream's fixes for this issue:

​PR 11772 - gimp2: update to 2.10.24

[i0ntempest]

In e45d4a0803937e58c8592635b7dfe24f4ac01e5b/macports-ports (master):

gimp2: update to 2.10.24 & various fixes

closes: #61799
closes: #63029
closes: #63028
closes: #59481

[i0ntempest]

Ok so macOS 12 is out and the problem is back... great. Should we reopen?

[mascguy (Christopher Nielsen)]

Yes, let's reopen; this issue still exists for me on 10.14 and 10.15 as well, despite upstream's patches.

Sadly, I still can't create a working Big Sur VM, on my aging 2008-era MacPro. So I'll have to lean on yourself and others, to validate things in Big Sur. (And Monterey too, for that matter.)

As for the issue: Given that we're using the correct upstream patches, my suspicion is that the macOS version being reported within GTK2 doesn't match with reality. Particularly given that the various fixes are only enabled, at runtime, via that version check.

Still need to dig into this a bit more, with temporary debug output within GTK2, to diagnose further.

[mascguy (Christopher Nielsen)]

One possible approach: Split the patches into smaller, more granular chunks, that can be applied individually by the portfile [depending on the macOS version we're building on]. And then remove the runtime version checks, which won't be necessary if the portfile properly decides what's necessary.

[Christopher Nielsen <mascguy@…>]

In 80aee331c8a613e100431fb7825a508d71864a0e/macports-ports (master):

gtk2: fix sluggish screen updates for 10.14 and 10.15

• Performance patches apply to 10.14 and 10.15 too, in addition to Big Sur and Monterey

Fixes: #59481

[Christopher Nielsen <mascguy@…>]

In 76377db241c8a5f4844083da60cee3c28029f034/macports-ports (master):

gtk2-devel: reconcile performance patches with gtk2
See: 80aee331c8a613e100431fb7825a508d71864a0e/macports-ports
See: #59481