Capabilities negotiation return Invalid State after 1st scan

[nabbla]

Hello!

I’m trying to use TWAIN without showing scanner GUI (have several scanners which ‘forget’ settings from there no matter what). First, I load source manager, then load source itself, set its resolution, pixel type, bitdepth and layout and it works like a charm – for a first time.

But when the first page is acquired and DISABLEDS is sent successfully, which should return source into state 4, where I can negotiate capabilities again, I can’t set another resolution, pixel type etc.: Invalid State is returned.

This occured with Mustek A3 1200s scanner, but that was expected in some sense, because its drivers caused headache before. But what’s more interesting, I’ve tried to use TWAIN sample Data Source and got the same response with it, too.

I’ve managed to fix my program by unloading source and loading it again before each settings change, but it doesn’t seem right.

Am I missing something?

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