[sane-devel] Release 1.0.33?

[Ralph Little]

Hi,

On 2021-08-29 11:26 a.m., Thierry Huchard wrote:
>> As an aside, I would also like to propose that we schedule a release of
>> the SANE frontends perhaps a short while after the backends' release.
>>
>> We have had a request to port our x* frontends to GTK3 (or 4?) and I am
>> currently working my way through that.
>> GTK4 has been released and GTK2 (GTK+) has been well and truly
>> deprecated to the point at which I fear that some distros might drop
>> support entirely.
>>
>> GTK porting is not something I have done before but it is an exercise
>> that is required for xsane also so the effort is worthwhile.
>>
>> The biggest deal seems to be the use of GtkPreview to render and manage
>> the preview window, which has been removed entirely from GTK3.
>> There will be a few other bits and pieces here and there I am sure.
> Hi Ralph,
>
> For the Gtk migration, I can help!
>
> Thierry

That would be really appreciated, thanks!

I would like to have a stab at the port unaided at least for the first 
pass because it is a good learning exercise for myself.
I mostly learn by doing but if you could take a look through my 
first-pass port, when I check it in, to see if there is anything that I 
have done badly or if there is a better way then that would be excellent!

For the first pass, I am staying with GTK2 and removing deprecated 
features. That is mostly involved in reimplementing the GtkPreview 
functionality that is used in the Preview window of xscanimage. I am 
replacing it with a GtkDrawingArea and backing it with a data buffer 
using cairo_image_surface_create_for_data(), which is similar to what 
xscanimage is going at present so the changes are fairly minimal. The 
data buffer format will be slightly different but I don't think that 
should be an issue. xscanimage gradually adds data to the buffer as it 
comes in so the preview emerges as the image data is received.

I also have some ideas for implementing the selection area. At the 
moment it is a thin rectangle that is drawn across the preview image 
with the mouse. I'm thinking that a translucent mask with the selected 
area transparent might look very effective and modern and simple to do.

I'll let you know when I have something worth looking at! Any porting 
comments that you have are also appreciated.

Cheers,
Ralph