implement the fix the grid may be redefined in a document

[bwl21]

The hint in https://groups.google.com/forum/?fromgroups#!topic/prawn-ruby/nYfR9EBvygk should be implmentd.

I have created an application to show calendars. This is based on grid, and expected that I can redefine the grid within a Document.boundingbox.

In my application I have added:

module Prawn
  class Document

    # Defines the grid system for a particular document.  Takes the number of
    # rows and columns and the width to use for the gutter as the
    # keys :rows, :columns, :gutter, :row_gutter, :column_gutter
    #
    def define_grid(options = {})
      @grid = Grid.new(self, options)
      @boxes = nil  # see https://groups.google.com/forum/?fromgroups#!topic/prawn-ruby/nYfR9EBvygk
    end
  end
end

This allows to redefine the grid. Could this be part of the official Prawn.

[traels]

1 vote for merging this into Prawn - or update the manual to tell that grid is per document.
I wasted 2 hours of my life before finding this - thank you for showing me a fix @bwl21 :)

[practicingruby]

@traels:

I am not super familiar with the grid code, but having it be global is definitely weird when most things in Prawn can be nested relative to a bounding box.

If you want to work on a patch or update the documentation, it'd certainly be welcome. Please submit a pull request, and let me know if you need help figuring out how to implement it!

[traels]

The update bwl21 has posted sort of makes sense - I have just implemented in my app. I can't really see that applying that fix should break anything.

As far as I can see the problem is somewhere around https://github.com/prawnpdf/prawn/blob/stable/lib/prawn/layout/grid.rb#L20 which could be a performance thing but has the drawback that the boxes are not rewritten when a new grid is defined.

I'll try to update the manual to say that grid is defined per document.

[practicingruby]

What we have here isn't a patch, it's just showing a line of code we could change if we wanted to prepare a patch. It has no tests or examples, and so it's not in a reviewable state. If we simply changed this line in Prawn, nothing would stop us from breaking it or misunderstanding the intention in a future release.

A pull request with tests and a clear example, and any necessary documentation updates is definitely worth reviewing though!