Preparation of score images: fine-rotate to optimise notation lines orientation

[Bacchushlg]

In some cases it is helpful to have an automatic / or manual fine rotation function for the pages of a score. While the transcription seems to work even with rotated images of up to 5°, the manual editing is easier if the orientation is almost correct. This applies especially in case of the usage of the lasso, e.g. for selection of the lyrics.

If automation is possible: fine. If not, manual rotation is helpful, too.

[hbitteur]

Don't you think we have many tools out there to fine rotate an image? See Google photos for example. I clearly understand the need for the end-user, much less for the poor Audiveris developer who would have to re-invent the wheel... Sigh! :-)

[Bacchushlg]

I thought of something that can "easily" be implemented from some simple image handling library. Just for those users who are not familiar with image editing (I assume there are a lot of them...). It also is very helpful for working with pdf files - avoiding to convert to image file(s) before.

[hbitteur]

OK, let's address this after 5.2 is released.

[anno73]

I do understand that there are a whole lot of image editing tools out there. And I do understand that the main focus of audiveris is to recognize "music artifacts". Nevertheless I would find it a huge benefit for the average and occasional user (like me) to have a sort of one-stop-shopping experience: ideally, take a photo (sometimes of questionable quality because of lighting and curved source pages), load it to audiveris and get a pdf with nice straight horizontal lines. Therefore I appreciate you addressing this issue (maybe you can also address trapezoid distortion then :-)

[hbitteur]

I thought of something that can "easily" be implemented from some simple image handling library. Just for those users who are not familiar with image editing (I assume there are a lot of them...).

Some time ago, we used JAI (Java Advanced Imaging) library for potential de-warping of the input image. De-warping is more general than simple rotating.

I discarded this feature to remove Audiveris dependency on JAI which seems to not be truely open source. This impeded the building of a Linux installer, so I sacrified de-warping.

Bad luck, today we still have a transitive dependency on JAI because of some method within JPodRenderer library. :-( So, I may re-activate JAI-based image edition some day...