#!/usr/bin/env python3
"""Cut inline type-specimen glyphs out of a page at native resolution.

  crop_inline.py PAGE NAME=SPEC [NAME=SPEC ...]
SPEC is an ink-run index from work/boxes<PAGE>.json, optionally with a side:
  13        the whole run
  60:right  split the run at its widest internal gap, keep the right part
  14:trimright  drop only the rightmost element (a trailing comma, say)
  6:mid       drop the first and last elements, keeping the middle
  5:last      keep what follows the final gap (when the widest gap is elsewhere)
  5+59        start 59 px into the run (last resort: no gap is detectable)
  4~610       keep only the leftmost 610 px of the run
  0-11      the span from run 0 to run 11 (for a whole specimen line)
Writes plates/inline/p<PAGE>-<NAME>.png (1-bit when the source is bitonal)."""
import subprocess, io, json, sys
import numpy as np
from PIL import Image

page = int(sys.argv[1])
boxes = json.load(open(f"work/boxes{page}.json"))
png = subprocess.run(["pdftoppm","-png","-r","300","-f",str(page),"-l",str(page),
                      "source/10731406.pdf"], capture_output=True).stdout
im = Image.open(io.BytesIO(png)).convert("L")
arr = np.array(im) < 128

def split(box, side):
    x0, y0, x1, y1 = box
    col = arr[y0:y1, x0:x1].mean(0) > 0.004
    gaps, i = [], 0
    while i < len(col):
        if not col[i]:
            j = i
            while j < len(col) and not col[j]: j += 1
            gaps.append((j-i, i, j)); i = j
        else: i += 1
    gaps = [g for g in gaps if g[1] > 0 and g[2] < len(col)]
    if not gaps: return box
    if side in ("left", "right"):
        _, gi, gj = max(gaps)
        return (x0, y0, x0+gi, y1) if side == "left" else (x0+gj, y0, x1, y1)
    if side == "last":       # keep only what follows the FINAL gap
        return (x0+gaps[-1][2], y0, x1, y1)
    if side == "first":      # keep only what precedes the FIRST gap
        return (x0, y0, x0+gaps[0][1], y1)
    if side == "mid":        # drop the first and last elements (`, G ,')
        return (x0+gaps[0][2], y0, x0+gaps[-1][1], y1)
    if side == "trimright":  # drop the last element only
        _, gi, gj = gaps[-1]
        return (x0, y0, x0+gi, y1)
    _, gi, gj = gaps[0]      # trimleft: drop the first element only
    return (x0+gj, y0, x1, y1)

for spec in sys.argv[2:]:
    name, s = spec.split("=")
    side = None
    if ":" in s: s, side = s.split(":")
    off = 0; keep = None
    if "~" in s:                 # 4~610 — keep only the leftmost 610 px of run 4
        s, k = s.split("~")
        keep = int(k)
    if "+" in s:                 # 5+59 — start 59 px into run 5, when the space
        s, o = s.split("+")      # between a word and the glyph is too noisy to
        off = int(o)             # register as a gap
    if "-" in s:
        a, b = (int(v) for v in s.split("-"))
        box = (min(boxes[i][1] for i in range(a,b+1)), min(boxes[i][2] for i in range(a,b+1)),
               max(boxes[i][3] for i in range(a,b+1)), max(boxes[i][4] for i in range(a,b+1)))
    else:
        box = tuple(boxes[int(s)][1:])
    if side: box = split(box, side)
    if off: box = (box[0]+off, box[1], box[2], box[3])
    if keep: box = (box[0], box[1], box[0]+keep, box[3])
    c = im.crop(box)
    if len(np.unique(np.array(c))) <= 2: c = c.point(lambda v: 255 if v > 128 else 0).convert("1")
    out = f"plates/inline/p{page:04d}-{name}.png"
    c.save(out, optimize=True); print(out, c.size)