I was thinking about this last night and wondered whether, or not, there would be a case for implementing a full zoom in and out function. For example, a held tap on the "+" icon would zoom all the way in and a held tap on the "-" icon would zoom all the way out. After all, you've already implemented 50% of that function inadvertently
I know the you don't like held taps, but I think in this case they would be justified.
Anyway... for your consideration
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