Initial commit

mangautils.py

@@ -0,0 +1,126 @@
+#!/usr/bin/env python3
+
+from sys import stderr
+from fpdf import FPDF
+from natsort import natsorted
+from pathlib import Path
+from argparse import ArgumentParser
+from PIL import Image
+
+class MangaPDF(FPDF):
+    page_height = 210
+    page_width = 297
+    image_margin = 4.2
+    text_margin = 7
+    
+    def write_image(self, path: Path, right_side: bool):
+        name = str(path)
+        if path.suffix == ".jpg" or path.suffix == ".jpeg":
+            info = self._parsejpg(name)
+        elif path.suffix == ".png":
+            info = self._parsepng(name)
+        else:
+            raise ValueError("invalid image extension")
+        i = len(self.images) + 1
+        info["i"] = i
+        self.images[name] = info
+        iw = info["w"]
+        ih = info["h"]
+        image_ratio = iw / ih
+        pw = self.page_width / 2 - self.image_margin - self.image_margin
+        ph = self.page_height - self.image_margin - self.image_margin
+        page_ratio = pw / ph
+        px = ((self.page_width / 2) if right_side else 0) + self.image_margin
+        py = self.image_margin
+        if image_ratio > page_ratio:
+            w = pw
+            h = ph * (page_ratio / image_ratio)
+            x = px
+            y = py + (ph - h) / 2
+        else:
+            w = pw * (image_ratio / page_ratio)
+            h = ph
+            x = px + (pw - w) / 2
+            y = py
+        self._out(f"q {w * self.k:.2f} 0 0 {h * self.k:.2f} {x * self.k:.2f} {(self.h - (y + h)) * self.k:.2f} cm /I{i} Do Q")
+
+    def text_width(self, text: str) -> float:
+        return sum(self.current_font["cw"].get(c) for c in text) * self.font_size / 1000.0
+
+    def write_page_num(self, page_num: int, right_side: bool):
+        x = (self.page_width - self.text_margin - self.text_width(str(page_num))) if right_side else self.text_margin
+        y = self.page_height - self.text_margin
+        self._out(f"BT {x * self.k:.2f} {(self.h - y) * self.k:.2f} Td ({page_num}) Tj ET")
+
+    def __init__(self, left_pages: list[tuple[int, Path | None]], right_pages: list[tuple[int, Path | None]]):
+        super().__init__(orientation = "landscape", unit = "mm", format = (self.page_height, self.page_width))
+        self.set_font(family = "Times", style = "B", size = 12)
+        self.set_text_color(0, 0, 0)
+        for (left_page_num, left_img_path), (right_page_num, right_img_path) in zip(left_pages, right_pages):
+            self.add_page()
+            if left_img_path is not None:
+                self.write_image(left_img_path, False)
+                self.write_page_num(left_page_num, False)
+            if right_img_path is not None:
+                self.write_image(right_img_path, True)
+                self.write_page_num(right_page_num, True)
+
+def iter_img_paths(imgs_path: Path):
+    img_extensions = ["jpg", "jpeg", "png"]
+    return (
+        img_path
+        for img_path_iter in (
+            imgs_path.rglob(f"*.{ext}")
+            for ext in img_extensions
+        )
+        for img_path in img_path_iter
+        if img_path.is_file()
+    )
+
+def build_pdf(imgs_path: Path, num_blanks: int = 0):
+    blanks = [None] * num_blanks
+    img_paths = blanks + natsorted(iter_img_paths(imgs_path))
+    empty_pages = [None] * ((4 - (len(img_paths) % 4)) % 4)
+    padded_img_paths = img_paths + empty_pages
+    num_pages = len(padded_img_paths)
+    middle_index = num_pages // 2
+    page_info = list(enumerate(padded_img_paths, 1 - num_blanks))
+    back_right_pages = page_info[:middle_index:-2]
+    back_left_pages = page_info[:middle_index:2]
+    front_right_pages = page_info[1:middle_index:2]
+    front_left_pages = page_info[num_pages-2:middle_index-1:-2]
+    MangaPDF(back_left_pages, back_right_pages).output(imgs_path.with_name(f"{imgs_path.stem}-back.pdf"), "F")
+    MangaPDF(front_left_pages, front_right_pages).output(imgs_path.with_name(f"{imgs_path.stem}-front.pdf"), "F")
+
+def split_images(imgs_path: Path):
+    for img_path in iter_img_paths(imgs_path):
+        img = Image.open(img_path)
+        if img.width > img.height:
+            mid = img.width // 2
+            img.crop((mid, 0, img.width, img.height)).save(img_path.with_stem(f"{img_path.stem}a"))
+            img.crop((0, 0, mid, img.height)).save(img_path.with_stem(f"{img_path.stem}b"))
+            img_path.unlink()
+
+def main():
+    parser = ArgumentParser("mangautils")
+    subparsers = parser.add_subparsers(dest = "command", required = True, help = "the command to run")
+    split_parser = subparsers.add_parser("split", help = "split two page spreads in the given images")
+    split_parser.add_argument("input", help = "the directory containing the images")
+    build_parser = subparsers.add_parser("build", help = "create a pdf from the given images")
+    build_parser.add_argument("input", help = "the directory containing the images")
+    build_parser.add_argument("-b", "--blanks", default = 0, type = int, help = "number of blank pages to add at the start (default: %(default)s)")
+    args = parser.parse_args()
+    
+    try:
+        input_path = Path(args.input)
+        match args.command:
+            case "split":
+                split_images(input_path)
+            case "build":
+                build_pdf(input_path, args.blanks)
+    except Exception as e:
+        print(f"error: {e}", file = stderr)
+        exit(1)
+
+if __name__ == "__main__":
+    main()