Add PDF support in attachment preview dialog

[w15eacre]

Add PDF support in attachment preview dialog

To preview the first page of a PDF file you need poppler >= 23.1.0.
Add an optimization to resize images.

Screenshots

Before the optimization

After

Testing strategy

• Added tests for a new type of attachments. Unit tests were implemented to verify the functionality of the new attachment type.
• Manually. Performed manual testing to ensure the correct behavior of the new attachment feature in various scenarios.

Type of change

• ✅ New feature (change that adds functionality)

[w15eacre]

@droidmonkey Could you explain how to add these dependencies for the build?

[droidmonkey]

Will need to add it to the vcpkg.json and CMakeLists.txt, probably as an optional dependency

On the CI boxes we will install it

[w15eacre]

Great!
I figured out how to add a dependency and will do that this week. And I'll try adding UI tests because the dialog has become more complex.

[w15eacre]

@droidmonkey I couldn’t find qt5-image-formats-plugin-pdf in the package manager. Can I use Poppler instead?

[droidmonkey]

Poppler seems well regarded and supported, i don't have an issue with it.

[w15eacre]

@droidmonkey I need your help. The CI/CD environment doesn’t have the required library (Poppler). Do I need to add a new CMake option to enable or disable this feature?

[droidmonkey]

Don't worry about the CI env, I'll get it all set once your work is ready for review.

[w15eacre]

I have finished it. I think previewing the first page is enough, but there’s no problem with adding all pages to the preview.

[w15eacre]

@droidmonkey Do you need some more information to update CI?

[droidmonkey]

No i just haven't had time

[xboxones1]

@w15eacre, @droidmonkey
Why can I create a text document with the ability to edit it, but then why can't I modify a text attachment? I thought it would be a simple text editor since this was closed #3383

[droidmonkey]

That's actually a good point

[w15eacre]

@w15eacre, @droidmonkey

Why can I create a text document with the ability to edit it, but then why can't I modify a text attachment? I thought it would be a simple text editor since this was closed #3383

We can only edit text attachments. How do you see this implemented if there are many files we cannot edit? Should we just enable or disable the edit button in such cases?

[xboxones1]

Only allow editing of supported text formats. I thought that a simple text editor would be implemented, that's why I suggested to see how it is implemented in keepass.

[w15eacre]

I will implement this in the next PR because I think it will be a big change

[droidmonkey]

How do you see this implemented if there are many files we cannot edit?

Introduce a function for "editable Mime-Type" detection. If it's editable you set the preview as not read-only and when you close the preview you ask if you want to save the changes

[droidmonkey]

@w15eacre I am getting very poor results with all PDF renders (this is on Windows):

I am going to reserve this for 2.8.0 since it also introduces a dependency.

[w15eacre]

@droidmonkey
That's interesting because I don't have any issues with PDF render quality(Linux). I need to check it on Windows.