rougier · April 25, 2026 11:41 · rougier · Apr 25, 2026
diff --git a/noisify.py b/noisify.py
 #! /usr/bin/env python
 """
 Copyright (c) 2026 N.Rougier

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 """

 import os, sys, io, random, argparse, os
 from pypdf import PdfReader, PdfWriter
 from reportlab.pdfgen import canvas
 from reportlab.lib.pagesizes import A4
 from reportlab.lib.units import mm

 def add_squares(input_path, ratio, size_mm, output_path):
    """
    Overlay random black squares onto a PDF aligned to a grid of square size.

    Parameters
    ----------
    input_path : str
        The file system path to the source PDF file.
    ratio : float
        The desired percentage of the page surface area to be covered by 
        black squares (e.g., 10.0 for 10% coverage).
    size_mm : int
        The side length of the squares in millimeters (1 to 10).
    output_path : str
        The file system path where the modified PDF will be saved.

    Raises
    ------
    FileNotFoundError
        If the input_path does not point to an existing file.
    """
    if not os.path.exists(input_path):
        print(f"Error: The file '{input_path}' was not found.")
        sys.exit(1)

    try:
        reader = PdfReader(input_path)
        writer = PdfWriter()
        
        # A4 Dimensions
        A4_WIDTH_MM = 210
        A4_HEIGHT_MM = 297
        
        # Grid Logic: Calculate how many columns and rows fit on the page
        cols = A4_WIDTH_MM // size_mm
        rows = A4_HEIGHT_MM // size_mm
        
        # Area Calculation
        A4_AREA_MM2 = A4_WIDTH_MM * A4_HEIGHT_MM
        square_area_mm2 = size_mm ** 2
        num_squares = int((A4_AREA_MM2 * (ratio / 100)) / square_area_mm2)
        
        # Total possible grid slots
        total_slots = cols * rows
        if num_squares > total_slots:
            num_squares = total_slots
            print(f"Warning: Requested ratio exceeds grid capacity. Using max: {num_squares} squares.")

        print(f"\n--- PDF Square Overlay Tool (Grid-Aligned) ---")
        print(f"Input:  {input_path}")
        print(f"Grid:   {cols} cols x {rows} rows ({size_mm}mm steps)")
        print(f"Ratio:  {ratio}% ({num_squares} squares per page)")

        for page_num in range(len(reader.pages)):
            packet = io.BytesIO()
            can = canvas.Canvas(packet, pagesize=A4)
            can.setFillColorRGB(0, 0, 0)
            
            # Create a list of all possible (col, row) indices and pick N unique ones
            # This ensures NO overlapping, making the 10% surface area mathematically perfect.
            all_possible_indices = [(c, r) for c in range(cols) for r in range(rows)]
            selected_indices = random.sample(all_possible_indices, num_squares)
            
            for c_idx, r_idx in selected_indices:
                x_pts = (c_idx * size_mm) * mm
                y_pts = (r_idx * size_mm) * mm
                can.rect(x_pts, y_pts, size_mm * mm, size_mm * mm, fill=1, stroke=0)
            
            can.save()
            packet.seek(0)
            
            overlay_pdf = PdfReader(packet)
            existing_page = reader.pages[page_num]
            existing_page.merge_page(overlay_pdf.pages[0])
            writer.add_page(existing_page)

        with open(output_path, "wb") as output_file:
            writer.write(output_file)
        print(f"Output: {output_path}")
        print(f"Status: Success\n")

    except Exception as e:
        print(f"An error occurred: {e}")

 if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Add grid-aligned random squares to a PDF.")
    
    parser.add_argument("input", nargs='?', help="Path to the source PDF file")
    parser.add_argument("-r", "--ratio", type=float, default=10.0, 
                        help="Percentage of page coverage (default: 10)")
    parser.add_argument("-s", "--size", type=int, default=1,
                        help="Square size in mm (integer), between 1 and 10 (default: 1)")
    parser.add_argument("-o", "--output", help="Output file name (optional)")
    args = parser.parse_args()
    if not args.input:
        args.input = input("Please enter the path to the input PDF: ").strip()
        if not args.input:
            sys.exit(1)
    if not (1 <= args.size <= 10):
        print("Error: Square size must be an integer between 1 and 10 mm.")
        sys.exit(1)
    if not args.output:
        base_name = os.path.splitext(args.input)[0]
        args.output = f"{base_name}-{args.ratio}pct-{args.size}mm-grid.pdf"
    add_squares(args.input, args.ratio, args.size, args.output)
	#! /usr/bin/env python
	"""
	Copyright (c) 2026 N.Rougier

	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is
	furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in all
	copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	SOFTWARE.
	"""

	import os, sys, io, random, argparse, os
	from pypdf import PdfReader, PdfWriter
	from reportlab.pdfgen import canvas
	from reportlab.lib.pagesizes import A4
	from reportlab.lib.units import mm

	def add_squares(input_path, ratio, size_mm, output_path):
	"""
	Overlay random black squares onto a PDF aligned to a grid of square size.

	Parameters
	----------
	input_path : str
	The file system path to the source PDF file.
	ratio : float
	The desired percentage of the page surface area to be covered by
	black squares (e.g., 10.0 for 10% coverage).
	size_mm : int
	The side length of the squares in millimeters (1 to 10).
	output_path : str
	The file system path where the modified PDF will be saved.

	Raises
	------
	FileNotFoundError
	If the input_path does not point to an existing file.
	"""
	if not os.path.exists(input_path):
	print(f"Error: The file '{input_path}' was not found.")
	sys.exit(1)

	try:
	reader = PdfReader(input_path)
	writer = PdfWriter()

	# A4 Dimensions
	A4_WIDTH_MM = 210
	A4_HEIGHT_MM = 297

	# Grid Logic: Calculate how many columns and rows fit on the page
	cols = A4_WIDTH_MM // size_mm
	rows = A4_HEIGHT_MM // size_mm

	# Area Calculation
	A4_AREA_MM2 = A4_WIDTH_MM * A4_HEIGHT_MM
	square_area_mm2 = size_mm ** 2
	num_squares = int((A4_AREA_MM2 * (ratio / 100)) / square_area_mm2)

	# Total possible grid slots
	total_slots = cols * rows
	if num_squares > total_slots:
	num_squares = total_slots
	print(f"Warning: Requested ratio exceeds grid capacity. Using max: {num_squares} squares.")

	print(f"\n--- PDF Square Overlay Tool (Grid-Aligned) ---")
	print(f"Input: {input_path}")
	print(f"Grid: {cols} cols x {rows} rows ({size_mm}mm steps)")
	print(f"Ratio: {ratio}% ({num_squares} squares per page)")

	for page_num in range(len(reader.pages)):
	packet = io.BytesIO()
	can = canvas.Canvas(packet, pagesize=A4)
	can.setFillColorRGB(0, 0, 0)

	# Create a list of all possible (col, row) indices and pick N unique ones
	# This ensures NO overlapping, making the 10% surface area mathematically perfect.
	all_possible_indices = [(c, r) for c in range(cols) for r in range(rows)]
	selected_indices = random.sample(all_possible_indices, num_squares)

	for c_idx, r_idx in selected_indices:
	x_pts = (c_idx * size_mm) * mm
	y_pts = (r_idx * size_mm) * mm
	can.rect(x_pts, y_pts, size_mm * mm, size_mm * mm, fill=1, stroke=0)

	can.save()
	packet.seek(0)

	overlay_pdf = PdfReader(packet)
	existing_page = reader.pages[page_num]
	existing_page.merge_page(overlay_pdf.pages[0])
	writer.add_page(existing_page)

	with open(output_path, "wb") as output_file:
	writer.write(output_file)
	print(f"Output: {output_path}")
	print(f"Status: Success\n")

	except Exception as e:
	print(f"An error occurred: {e}")

	if __name__ == "__main__":
	parser = argparse.ArgumentParser(description="Add grid-aligned random squares to a PDF.")

	parser.add_argument("input", nargs='?', help="Path to the source PDF file")
	parser.add_argument("-r", "--ratio", type=float, default=10.0,
	help="Percentage of page coverage (default: 10)")
	parser.add_argument("-s", "--size", type=int, default=1,
	help="Square size in mm (integer), between 1 and 10 (default: 1)")
	parser.add_argument("-o", "--output", help="Output file name (optional)")
	args = parser.parse_args()
	if not args.input:
	args.input = input("Please enter the path to the input PDF: ").strip()
	if not args.input:
	sys.exit(1)
	if not (1 <= args.size <= 10):
	print("Error: Square size must be an integer between 1 and 10 mm.")
	sys.exit(1)
	if not args.output:
	base_name = os.path.splitext(args.input)[0]
	args.output = f"{base_name}-{args.ratio}pct-{args.size}mm-grid.pdf"
	add_squares(args.input, args.ratio, args.size, args.output)
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