Improve memory pressure while exporting GIFs

[SergioEstevao]

This PR updates the exporting loops for creating GIF to be wrapped with autorelease blocks so the memory pressure is smaller when exporting then.

Related bug: https://jira.tumblr.net/browse/PROD-15147

How to test:

• Start the sample project
• Try to export a larger GIF ( you can get a GIF here: https://zikkimyeyin.tumblr.com/post/651438616631033856 )
• Check that the memory being used does not go over the limits.

[pinarol]

I used the iPhone 8 Plus (iOS 14.4) simulator to test this but I am having this assertion failure after these steps:

• Open example app
• Tap "Open Kanvas Dashboard"
• Tap on the media library icon on the bottom left
• Select the gif here https://zikkimyeyin.tumblr.com/post/651438616631033856 (I had dragged&dropped it into the sim, so it is now in the device lib)
• Tap on the Post button in the next screen (The circle blue one with arrow)
• Crash:

[pinarol]

Another thing, Tumblr was not depending on the main branch, not sure about the most up to date state but you may need to target another branch.

[SergioEstevao]

You need to activate the Metal options on the initial screen.

…

On 1 Jun 2021, 12:02 +0100, Pinar Olguc ***@***.***>, wrote: Another thing, Tumblr was not depending on the main branch, not sure about the most up to date state but you may need to target another branch. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[danielebogo]

@SergioEstevao Pinar is right. You have to merge this first and then cherry pick this commit in a new PR targeting a base branch created from 1.0.3 tag, also bumping the version to 1.0.4 for CanvasKamera.
Tumblr doesn't use Kanvas yet, but its old version.

[pinarol]

OK I can confirm that the the crash doesn't happen anymore.

Even though I think autoreleasepool is not the most ideal solution it is prolly the most time efficient one currently so LGTM. 👍

(Don't forget to update the target branch.)

[danielebogo]

@pinarol I think this can be merged on main. We can cherry pick the commit on a new base so the fix will be there even when we will update to the most recent Kanvas

[pinarol]

Ok then 👍