Use proper units when setting preferredFramesPerSecond

[bdolman]

preferredFramesPerSecond expects frames-per-second, rather than the
fractional interval expected by frameInterval.

For example, frameInterval=2 is the equivalent (on most devices) of
preferredFramesPerSecond=30.

This issue was introduced in #552

It's likely this fixes #570

[garrettmoon]

Thank you for fixing!

[garrettmoon]

Can you address:

    - WARN  | [PINRemoteImage/Core, PINRemoteImage/OSX, PINRemoteImage/WebP, and more...] xcodebuild:  /Users/runner/work/PINRemoteImage/PINRemoteImage/Source/Classes/AnimatedImages/PINAnimatedImageView.m:226:15: warning: unused variable 'frameRate' [-Wunused-variable]
29

And I'll merge?

[bdolman]

@garrettmoon Sure thing. I would like to move the frameRate calculation closer to its use, like this:

#if PIN_TARGET_IOS
        if (@available(iOS 10.0, tvOS 10.0, *)) {
            // Convert from display link fractional value to fps (note: frameInterval is always at least 1)
            NSInteger frameRate = ceil([PINAnimatedImage maximumFramesPerSecond] / ((double) frameInterval));
            _displayLink.preferredFramesPerSecond = frameRate;
        } else {
#endif

Rather than doing the calculation up above when it might not be used, but I was concerned about this comment:

// Get frame interval before holding display link lock to avoid deadlock
    NSUInteger frameInterval = self.animatedImage.frameInterval;

I didn't know if I risked creating a deadlock by doing it after referencing the display link. Do you know if that would be safe?

[garrettmoon]

Ah! Please remove that comment, I believe it copy-pasta'd it from the version I wrote in Texture. It's not relevant here since this class is designed to access the displayLink only on main.

[bdolman]

Perfect! I'll address that now.

[bdolman]

I'm not sure why the testResumeSkipCancelation test failed, since it succeeded for me locally.

[garrettmoon]

I'm not sure why the testResumeSkipCancelation test failed, since it succeeded for me locally.

Seems to be flakey, I'll rerun.