The calibration with a credit card would I think be easier if one corner of the calibration rectangle was in a fixed position, so moving the slider would only change the other three corners. The fixed rectangle should probably be the one on the bottom left.

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artiomyak 4 days ago | parent [-]

Working on a fix

	▲	Valgrim 3 days ago \| parent [-]
		Also my recommendation: -Make the card vertical instead of horizontal (phones are held vertically) -Add a +/- bottom on each end of the slider for fine tuning the ppi by 0.1 increment or lower, -Allow to manually change the value in the field