Re: `info` swallows vertical space and indentation after `@image`

[Gavin Smith]

On Fri, Apr 16, 2021 at 08:46:30PM +0000, Werner LEMBERG wrote:
> 
> [commit 2a15ed35d]
> 
> 
> Consider this example file `foo.texi`
> 
> ```
> @node Top
> 
> @image{test,,,foo,}
> 
> bar
> 
> baz
> 
> @bye
> ```
> 
> If processed with
> 
>   makeinfo `foo.texi`
> 
> and viewed with `info ./foo.info` I get the following output:
> 
> ```
> Up: (dir)
> 
> [foo]
> bar
> 
>    baz
> ```
> 
> I see two problems.
> 
> (1) The empty line after the image is missing.
> (2) There is no indentation of `bar`.  This is most likely a consequence
>     of (1).
> 
> For me, this looks like a bug.

I acknowledge it's a bug, at least the first point.  It's related to the
fact when the document is parsed, the image is not viewed as being part
of a paragraph - it is a "top level" object within the node.  If there is
extra text after the image, thus -

> @node Top
> 
> @image{test,,,foo,} aaa
> 
> bar
> 
> baz
> 
> @bye

- then there is a line added after the paragraph including the image.

The second point is not a bug because "bar" is the first paragraph in the
node so doesn't get indented.

The parse tree is like:

        {
          'args' => [
            {
              'contents' => [
                {
                  'text' => 'image',
                  'parent' => {}
                }
              ],
              'type' => 'brace_command_arg',
              'parent' => {}
            }
          ],
          'cmdname' => 'image',
          'contents' => [],
          'line_nr' => {
            'line_nr' => 3,
            'file_name' => 'test.texi',
            'macro' => ''
          },
          'extra' => {
            'input_perl_encoding' => 'utf-8'
          },
          'parent' => {}
        },
        {
          'parent' => {},
          'text' => '
'
        },
        {
          'text' => '
',
          'parent' => {},
          'type' => 'empty_line'
        },
        {
          'parent' => {},
          'contents' => [
            {
              'text' => 'baz
',
              'parent' => {}
            }
          ],
          'type' => 'paragraph'
        },

After the image there is an element without a type, containing the newline
after the image.  I am guessing that that newline is not output.

Looking at the code, I think a line is being added after the image by the
code in Plaintext.pm in _convert, where the comment says "First handle
empty lines", but there should have been another newline output before
this.

I haven't worked out where the extra newline should be output and it could
take me a while to do this, and I don't know if I will have time anytime
soon to work this out, so help on this would be appreciated.

Another option is to always include an image inside a paragraph, and
never have "free" images, but this would change the HTML output to
wrap <img> inside <p>, which would be disruptive and maybe not correct.