Table header breaks up on multipage pdfs

[Bharat311]

Hi, I was using an earlier version of the prawn gem and used it to render the following pdf:

But recently, when i upgraded to the latest master of prawn and prawn-tables for a fix of another issue, the following issue cropped up in the existing pdfs (which was not seen earlier).

Using the option { header: true }, the header was not properly rendered for the subsequent pages, here's a preview of the same pdf now (using the same code base):

Upon investigating, i found the below commit to be the reason for this broken behaviour:
prawnpdf/prawn@ed3d144

I am not completely sure as to how it works but it maybe due to using rowspans in the header. Any help in this regard would be greatly appreciated.

Thanks.

[hbrandl]

@Bharat311 Can you provide the code that causes this unexpected behaviour? Maybe even a failing test case?

[johnnyshields]

I work with @Bharat311. Here's code that reproduces the issue (see pages 2+):

        rows = []
        rows << [{content: '', borders: []}] * 6
        rows << [{content: 'foo', colspan: 6, height: 20, borders: []}]
        rows << [{content: 'bar', colspan: 2}] * 3
        100.times { rows << [{content: 'baz'}] * 6 }

        pdf.table(rows,
                  width: pdf.bounds.width,
                  header: 3, cell_style: {padding: 1}) do |table|
          table.row(1).columns(0...-1).borders = [:bottom]
        end

In particular it's the line table.row(1).columns(0...-1).borders = [:bottom] which seems to cause it.

[hbrandl]

@johnnyshields Thank you very much. I'll try to find some time next week to look into this issue. If you can provide a failing test case it will greatly speed up my work.

[johnnyshields]

I'm not really sure how to test this, but we can try to give it a look in the next week.

[Bharat311]

@hbrandl, i tried for several hours but couldn't add a failing test case for it. However, here's the minimal code that can be used to reproduce the issue:

pdf = Prawn::Document.new

rows = []
rows << [{content: "Header1", colspan: 6}]
rows << [{content: "Header2 (i)", colspan: 3}, {content: "Header2 (ii)", colspan: 3}]

50.times { rows << ["text"] * 6 }

pdf.table(rows, header: 2, cell_style: { borders: []}) do |table|
  table.rows(1).columns(0...-1).style(background_color: '888888')
  table.rows(1).columns(0...-1).borders = [:bottom]
end

The issue is because of the incorrect calculation of the header height for the 2nd page, i think this maybe due to multiple colspan rows in the header.

The above was working fine before and has been introduced in this commit:
prawnpdf/prawn@ed3d144

Currently, we are using the latest prawn-tables master without the above commit and it is working fine.

[hbrandl]

@Bharat311 @johnnyshields can you confirm that this fixes your issue?

[Bharat311]

@hbrandl, Thanks, this fixes our issue.

[johnnyshields]

@hbrandl looks good to me, thank you!