Thought the Apple vs Samsung dust was starting to settle? Think again.

Apple has lost another patent relevant to its perpetual twilight war with Samsung, again related to the ways users interact with touchscreen devices.

This time it was U.S. Patent No. 7,844,915, which describes the way a user can "pinch-to-zoom" and differentiates that function from scrolling.

The U.S. Patent and Trademark Office declared that the function was predicted by Patent No. 7,724,242, relating to gestures on touch screens and filed by W. Daniel Hillis and Bran Ferren in 2005.

The jury in the Apple-Samsung case previously ruled that 21 of 24 Samsung devices in question violated Apple's pinch-to-zoom patent, so this could have huge ramifications in that fight.

History repeats itself

This shouldn't come as a surprise - the USPTO "tentatively invalidated" this same Apple patent late last year, and this most recent announcement appears to just be confirmation of that decision.

And this isn't the first time this has happened. Last year the USPTO ruled that an Apple-owned patent relating to the "rubber band" function of scrolling touchscreen devices was invalid too.

That patent described the way the screen bounces when users reach the end of a page or document, and the jury found 21 of Samsung's devices infringed on it.

But that function no longer belongs to Apple either, casting yet more doubt on the already nebulous legal battle between Apple and Samsung.

Even more baffling is the fact that the patent apparently still stands in some countries, as a Japanese court found just last month that Samsung infringed on it.

Modern warfare

The big decision in the case of Apple vs. Samsung came last year when the jury awarded Apple more than $1.05 billion (about £688m, AU$1.15b), but the battle rages on nonetheless. That sum was later chopped down to around $598.9 million (about £386m, AU$651m) after the judge in the case found the jury awarded the difference improperly.

With the USPTO throwing all kinds of wrenches in Apple's holdings is it any wonder the two companies have been allowed to keep chipping away at each other in court?

Apple reportedly has two months to respond to the USPTO's most recent decision, and Apple can choose to appeal the decision and/or seek judicial review.

The two are due to return to court to settle the improperly calculated damages.

Via Android Community, Macworld