- Integrate pdf-tools.cc with the rest of the code
- What if an input page specifies /Rotate?
- Better error messages from instantiation
- page->index: use or remove
- rename page->bbox to page->image_box?
- "-f" switch

| # Position bbox on a new paper
| paper("a4")
| paper(w=210mm,h=297mm,pos=(t|b|c)(l|r|c))

| # Scale paper to a new size
| scaleto("a4")
| scaleto(w=210mm,h=297mm,pos=tl)

| # Fit image to a paper
| # If paper is given: scale image
| # If no paper is given: adjust paper to image + margins
| fit("a4")
| fit(w=, h=)
| margin= hmargin= vmargin=
| lmargin= rmargin= tmargin= bmargin=
| pos=

| # Adjust paper size
| expand(10mm)
| expand(h=10mm, v=20mm)
| expand(l=10mm, r=10mm, t=10mm, b=10mm)

| # Adjust image size (in terms of margins around)
| margins ... params like expand

cropmarks
	mark=box	# Box around image
	mark=cross	# Crosses in the corners
	mark=out	# Out-pointing half-crosses in the corners (default)
	mark=in		# In-pointing half-crosses
	pen=1pt		# Line width
	len=5mm		# Cross arm length
	dist=5mm	# Distance from border

| book
|	signature=<n>

# Crop to image box
crop
	bleed=5mm	# Allow bleeding over the image box

# Can be written as: mix(cat) { modulo(2){1}, modulo(2){2} }
duplex
	long-edge

| merge

| modulo
| 	half

| # Add an empty page after the current one
| add-blank
|	n=
|	paper...

# Set either:
#	- paper size + margins
#	- scale + margins
nup(hnum, vnum)
	by=rows/cols	# Filling order (default: rows)
	by=tile		# Tile with copies of a single page
	paper / w / h	# Specify paper size, default=copy from 1st image
	+ fit options (*margin, pos)
	crop		# Crop to image
	rotate=1	# Override rotation decision
	scale=1		# Override scaling factor
	hspace / vspace / space	# Distance between tiles
	+ cropmarks?

# Send pages to multiple pipes and merge their results
mix { ..., ..., ...}
	cat		# Concatenate results (default is interleave)
	cycle		# When one pipe ends earlier, cycle it from start
	pad		# When one pipe ends earlier, add blank pages