Scanned images often have a slight rotation because the scanner can not so easily be controlled in the placement of the sheets, and there is not enough time to devote it our entire life. In other cases, the scanner’s tray process several pages at the same time and sends them doing its best effort which doesn’t mean that results are ok.
As a result, we have pictures as the graph shown on the right, twisted.
Few desktop programs do this in a practical way, almost all allow rotation in 90 degrees but there are very little few of them that let you make a free manual adjustment (Spanish Idiom: ‘a ojo de buen cubero’).
The most practical solution is to use Picasa, Google’s free application for image management.
Image is selected from the corrections side panel, then choose the “straighten out” option.
Then in the right pane displays a bar with which you drag the adjustment until you think it is appropriate.
Then “apply” and go.
Additionally Picasa has its own virtues, although this and the option to export a large amount of documents to an specific size and format are the only ones I have used.
Here you can download Picasa.
Does anyone know another practical application for these purposes?