Martin Splitt from Google confirmed that Google Search does not measure title tags by the number of pixels. He said "that was a joke" when it was mentioned in the live version of the Search Off The Record podcast.
Martin Splitt said this on Twitter when it came up:
That was a joke 🙈
— Martin Splitt (@g33konaut) March 30, 2021
In that same podcast, which we covered over a month ago, Gary Illyes of Google did explain that Google does use more than what you see with the eye in your title tag. "Is there value in having title tags that are longer than the displayable text in the search snippets?" was asked and Gary Illyes said "yes."
So no, Google does not measure your title tags by pixels.
Forum discussion at Twitter.
