Add score viewing & PDF download

[Barmarel]

Please add to the android app:

• Ability to preview sheet music
• ability to download in pdf

[PeterNjeim]

Please note that the features of the app are not platform-dependent, there is no "Android app", just "the app".

"Previewing" sheet music is accomplished in two ways, either by downloading the MSCZ, then viewing it in a program (usually the MuseScore desktop program), or by downloading the PDF and displaying it as separate pages. It would be unnecessary to implement the previewing feature since you'd be "previewing" a sheet after you've already downloaded it, meaning it's essentially a "postview" at that point. As a result, the thumbnails are the only preview that will be available in the app.

As for PDF downloads, I'll see if I can implement it (note that downloading PDF is always possible via the Userscript, which is available on all platforms, including iOS).

[matj1]

@PeterNjeim Why is downloading PDF available in the userscript and not in the app?

I guess that the app could download the PDF the same way as how the userscript does it.

[PeterNjeim]

The userscript has access to the website which is where it downloads the PDF from. The app doesn't, and so either needs a different method, or needs to access the website in the background. I was going to use a similar method used in the command-line tool to download PDF, but the tools available to do it in Flutter (the framework the app uses) were limited, and so I opted not to implement it as it wasn't important as other tools could download it.

As for why not now, two reasons, one, the app has been patched for months now, and two, the command-line tool has also been patched, meaning my preferred method for getting this to work can't work anymore