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Begin implementing strategy selection

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Right now this is still unexposed to the users.
Pretty-printing the foliating plan is somewhat of
a problem. Hopefully they are always quite small.
This commit is contained in:
Selene Corbineau 2026-06-21 11:21:08 +02:00
parent e3e84692e3
commit 6566830258
1 changed files with 24 additions and 13 deletions
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37
foliator.py
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@ -39,7 +39,7 @@ def append_folio_A6(input_pdf, offset, size, append_to):
# num_sheets = max_folio_size * a + (max_folio_size - k) * b
# where k is minimal. We let n = max_folio_size and L = num_sheets.
# Note that when L > n^2, then k = 1 must succeed.
def find_partition(num_sheets, max_folio_size):
def find_partition_mink(num_sheets, max_folio_size):
max_a = num_sheets // max_folio_size
for k in range(1, max_folio_size):
# We want to solve a*k = L (mod n-k). This happens iff
@ -58,7 +58,12 @@ def find_partition(num_sheets, max_folio_size):
# substracting almost mprime.
candidate = max_a - tosub
if (candidate >= 0):
return (candidate, k)
b = (num_sheets - max_folio_size * candidate)//(max_folio_size - k)
return [max_folio_size] * candidate + [max_folio_size - k] * b
def find_partition_greedy(num_sheets, max_folio_size):
q = num_sheets//max_folio_size
return [max_folio_size] * q + [num_sheets - q*max_folio_size]
# Interprets input_pdf as a list of A6 pages, and appends to append_to with
# A5 pages using the following rules:
@ -66,23 +71,29 @@ def find_partition(num_sheets, max_folio_size):
# with "mirror around **short** edge"
# b. when grouped as consecutive sequences of max_folio_size or less, the printed
# sheets can be folded in the middle and assembled as a folio
def foliate_A6(input_pdf, max_folio_size=-1, append_to=PdfWriter()):
current_page = 0
def foliate_A6(input_pdf, strat_func, max_folio_size, append_to=PdfWriter()):
doc_length = len(input_pdf.pages)
writer = append_to
if max_folio_size < 0:
max_folio_size = doc_length
num_sheets = math.ceil(doc_length/4.0)
print("Using", num_sheets, "two-sided A5 sheets")
L = [num_sheets]
if max_folio_size > 0:
L = strat_func(num_sheets, max_folio_size)
if(np.sum(L) != num_sheets):
print("[ERROR] strategy gave", np.sum(L), " A5 sheets")
exit(1)
folio_page_size = 0
while(current_page < doc_length):
# max_folio_size is a number of _sheets_, each containing 4 pages
folio_page_size = min(doc_length - current_page, 4*max_folio_size)
current_page = 0
for l in L:
# l is a number of _sheets_, each containing 4 pages
folio_page_size = min(doc_length - current_page, 4*l)
append_folio_A6(input_pdf, current_page, folio_page_size, append_to)
current_page += folio_page_size
print("Dangling folio has",folio_page_size,"pages",
"(",int(math.ceil(folio_page_size/4.0)),"sheets).")
return writer
# Take an A5 printing plan, with odd/even pages being understood
@ -130,7 +141,7 @@ parser.add_argument("-fs", help="maximum folio size, in sheets",
args = parser.parse_args()
input_pdf = PdfReader(args.infile)
a5 = foliate_A6(input_pdf, args.fs)
a5 = foliate_A6(input_pdf, find_partition_greedy, args.fs)
if (args.a5):
a5.write(args.outfile)
else: