Using ContentStream#write makes GhostScript complain

[JasonBarnabe]

In an otherwise valid document, If I do

      contents.write('my text', {
          x: 30,
          y: 30,
          size: 8,
          leading: 8 * 1.2
      })

when I process the resulting file with GhostScript, it says

   **** Warning: Tf refers to an unknown resource name: F1 Assuming it's a font name.

   **** This file had errors that were repaired or ignored.
   **** The file was produced by: 
   **** >>>> GPL Ghostscript 9.16 <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

[JasonBarnabe]

Solution seems to be to first

page.add_font(Origami::Font::Type1::Standard::Helvetica.new.pre_build, :Helvetica)

and then

      contents.write('my text', {
          x: 30,
          y: 30,
          size: 8,
          leading: 8 * 1.2,
          font: :Helvetica,
      })

[gdelugre]

I'm still unsure what should be the correct behavior if no font is passed as an argument.

I could simply reuse the current font used in the graphics stack of the page.

[JasonBarnabe]

Any of these seem sensible to me:

• Make font a required argument
• Use a (working!) default font
• Use a font used elsewhere in the PDF (is there always at least one font?)

No matter what you choose, please document it and update the examples.