[cairo] Embedding EPS files

[Adrian Johnson]

On 10/11/21 20:00, Han-Wen Nienhuys wrote:
> Unfortunately, there is a more serious problem. None of the drawing
> commands issued after the EPS embedding make it to the PS output.

After painting the EPS image surface, the cairo source is still set to
the image surface for subsequent drawing operations. As there is no
overlap between the extents of the EPS image and subsequent drawing
operations, nothing is emitted.

Either wrap the cairo_set_source_surface(), cairo_paint() in
Cairo_outputter::eps_file() with a cairo_save()/cairo_restore() pair or
ensure cairo_set_source_rgb() is called before drawing operations that
require a solid source.