Samples reports generated in the backend

[leandroradusky]

Closes #1843 and #1900

Now, the samples reports are generated in the backend.

There are some slight changes in the look. The first page looks now like this:

Then the other two pages just contain the SVG files as they are downloaded.

For the sake of completeness, the ROC plot is also rendered OK, here is how it looks.

Some commentaries:

• There are no mockups for the reports and they were not used yet by users, said that the first table with the summary was modified to look like this since it looks better than before.
• In the second section, the confusion matrix, is not looking exactly the same as the webpage due to some limitations of the prawn-table library: round borders are not supported and spaces between cells are managed with the borders, and painting borders will fill the full space between cells.
• There was a correction of the error bars, since before the middle bar was a little short, not connecting the horizontal lines properly.
• There was a correction to have all the axes capitalized on the plots.
• The error bars were black with opacity, then they looked gray. This was corrected since they were looking black in the PDF but also they were looking black when opening the SVGs with some software like InkScape. Now, they look the same everywhere.
• The rendering code can be improved, but I want your input on the look of the stuff, if you give me the ok I move forward in improving this code (cc @ysbaddaden @diegoliberman)

Important (cc @julien, I need help in solving this): I'm posting the data in a newly created form, but I systematically get an Invalid Authenticity Token error which I don't know how to solve. I'm sure is a silly error but I didn't manage to solve it. Then I had to add the line skip_before_action :verify_authenticity_token which is only a transitory solution to make the feature to work.

I've tested with a lot of different conditions:

• All purposes
• Containing samples without results and not
• Long report names
• Different produced plots.
• Different browsers.
• Moving the threshold for the Challenge purpose (which trigger changes in the plots)

All of them worked correctly for me, but this issue needs in-depth testing.

CC @diegoliberman

[diegoliberman]

There are no mockups for the reports and they were not used yet by users, said that the first table with the summary was modified to look like this since it looks better than before.

I don't quite get this. The design (better than mockups) for the table and reports is here and it had been already implemented. I'm not sure if it looks better... Anyhow, I say ship it as is, my observation is no blocker at all.

[leandroradusky]

Hi @diegoliberman. Sorry because the name was misleading, here we're talking about the PDF exported for the samples report.

The second and third page looks quite the same, the first page now looks like this

As I mentioned above, what I decided to change is the summary, the first section. The Confussion Matrix section now looks slightly different than in the webpage because of the library that we use to generate the PDF report on the backend.

Let's chat if I'm not clarifying with this message :)

[leandroradusky]

Made the fixes to display the confusion matrix exactly as on the website (as for the SVGs, the grays are not handled with transparencies ─as in the project's CSSs─ but with grey colors, which is a limitation of prawn but looks super similar). The styling now is made in subclasses of Prawn::Table::Cell.

Also, the authenticity token problem was fixed with the form_tag tag thanks to the guidance of @ysbaddaden (Thanks!! :bowing_man:)

[leandroradusky]

I think I've addressed all the commentaries, if not, now let's sync :)

Thanks a lot for the guidance !!