Forums › TWAIN Classic › Transition from state 5 to 6 › Reply To: Transition from state 5 to 6
a messageloop must exist to use twain. and yeah have to wait for the source to send xferReady – sorry thats just how twain works.
you don’t want the user to anything?… surely the user has to at least signal that they want something scanned, push the big red scan button in the program or something…
but if your goal is just a little automation and you are looking for the settings to be applied without the user setting them up every time you’ll be ok.
One question. Are you planning for the user to setup the scanner at least once? The direction of my question is, if the user never sets up anything then they’ll get either default settings or the settings that are still in place from the last time they scanned something with another program (sota depends on the device). It doesn’t seem to me that this is what almost anyone really expects.
It seems to me (and granted it maybe only to me here) that users who are looking for automation usualy want some control of what is automated.
Or are you planning to code in every setting? The idea of coding in every setting is both a bunch of work and doomed (doomed, doomed I say moohoo haha…) the reason I don’t believe in coding in every setting is that all of the settings for a given device aren’t documented – that is the twain spec contains a basic set of capabilities but it leaves a lot of room for the device vendors to put in custom capabilites (that may be using custom values that you won’t have the docs for) and besides, a really fantastic configuration Ui is already built for most devices – the built in one. If you use EnabledsUiOnly in a setup phase, then the device Ui will pop up and when the user OKs the dialog you can (for most devices) query the device for the settings, then in step 2 (normal production) you can replay the settings back to the device. It works out pretty well for a number of reasons – you don’t have to put in miles of code to each and every setting and the device’s standard Ui will take care or those nasty custom caps for you – its a win-win. You can enable the device bring it online and have it run the saved configuration all without the user seeing a Ui, you can just tie it up behind a big red scan button (except for sources that don’t honor the ShowUi=False setting) the only input from the user that you have to have from the user is them clicking the big red button. and if you’re worried about waiting for the xferReady message, don’t. you can add code to handle that message, it shouldn’t take any longer than a regualr scan and the vast majority of it can be automated so that the user doesn’t have to much more than start the scanning.
And you’re welcome, we were all there once. Ask until you run out of questions or find me on IM, my contact details are on my profile.
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