Save options

[angstyloop]

New save options menu!

Uses introspection on the VIPS save operation, to choose the appropriate widgets and text to display for a given output image format.

Also removed trailing white space in imagesource.c and tilesource.c (while removing them from my own code with regex). I can redact those changes though if desired though.

[angstyloop]

Here is a small demo of the save options menu.

[angstyloop]

Some notes on how Valgrind was used to test this code for memory leaks:

https://github.com/jcupitt/vipsdisp/pull/14#issuecomment-1541156625

[jcupitt]

Hi again, I finally had some time to compile and test this. Nice work!

I noticed a few small things in a quick tryout:

• When showing option menus, you need to stop one before the end. The final element in a libvips enum is always LAST (so programs can get a count of the number of enum entries).

• I think I'd expect to be able to move the popup window containing the options, but it seems to be locked in place, I'm not sure why.

• I was able to get it to coredump pretty easily by adjusting the tiff save options. Try setting compression to jpeg, enabling tiling, and then saving several times.

I'll have a poke about in the code.

[jcupitt]

I think I'd make saveoptions into true widget, like infobar. So saveoptions.h would have something like:

#ifndef __SAVE_OPTIONS_H
#define __SAVE_OPTIONS_H

#define SAVE_OPTIONS_TYPE (save_options_get_type())

G_DECLARE_FINAL_TYPE( SaveOptions, save_options,
        VIPSDISP, SAVE_OPTIONS, GtkWindow )

SaveOptions *save_options_new( GtkWidget *parent, VipsOperation *operation );

#endif /* __SAVE_OPTIONS_H */

And a few other member functions, I guess. You'd be able to remove a lot of the member functions you have now if you reuse the gtkwidget / gtkwindow framework.

Shall I have a quick hack in another branch? I could sketch out a framework you could then cherry pick into this PR.

[jcupitt]

I made a basic save options framework: https://github.com/jcupitt/vipsdisp/compare/master...save-options

It does all the stuff with dialogs popping up and down, and the actual save operation, but doesn't have any of your nice options code. Hopefully you can just drop your stuff into that.

[jcupitt]

... I merged your option widget create and readout code into #20.

What do you think? I'm inclined to close this PR and do the finishing up in #20. Your work (and the credit for it) and in there now.

I feel bad for not pointing you in a clearer direction months ago :( I should have realized you were not using GtkDialog.

[angstyloop]

I've been preoccupied for the past week or so - thank you for grabbing the baton and running with it! I am proud to have contributed in any small way - it feels like a big accomplishment.

The heart of my contribution was the part that created widgets, populated them with data, and read that data to build the SaveOptions menu. As for the rest, I felt no shame hacking together GTK solutions the best I could. I always kept in mind that you might have to gut it entirely, but honestly it worked out better than I could have hoped!

I learned a lot in the process, and I learned more still by reviewing your changes. Being able to work on my humble contribution independently was really good for me. Thanks for including that stuff and modifying it to make it actually usable in VIPSDISP. This a cool feature, and I'm definitely proud of it!

[angstyloop]

I will go ahead and close this PR, which has been subsumed by PR #20.