Image Bleed, Crop Marks, and Imposition PDF Generator

This script takes an input image, adds bleed and crop marks (optionally), and generates an imposition PDF for printing multiple copies on a single sheet. It's highly configurable via a .ini file.

Features

• Bleed Addition: Adds bleed to the image using either "repeat" (extending edges) or "mirror" (reflecting edges) methods.
• Crop Marks: Generates crop marks for precise cutting after printing. Includes options for crop mark length, cut mark length and color (including "inverted" for dark images).
• Imposition: Creates a PDF with multiple copies of the image arranged on a single page, optimized for printing.
• Configuration: All settings (bleed size, crop mark details, paper size, orientation, number of copies, margins, spacing) are controlled via a layout.ini file.
• Default Configuration Generation: Can generate a default layout.ini file with sensible defaults.

Requirements

• Python 3.6+
• Pillow (PIL fork): pip install Pillow
• ReportLab: pip install reportlab

Usage

python layout.py <input_image> <output_pdf> [-c config_file] [--generate-config]

• <input_image>: (Required) Path to the input image file (e.g., image.jpg, flyer.png). Supports common image formats like JPG, PNG, etc.
• <output_pdf>: (Required) Path to the output PDF file (e.g., output.pdf).
• -c config_file / --config config_file: (Optional) Path to the configuration file. Defaults to layout.ini.
• --generate-config: (Optional) Generates a default layout.ini file and exits. Use this to create a starting configuration.

Example 1: Generate a default configuration file

python layout.py --generate-config

This will create layout.ini in the current directory. You can then edit this file to customize the settings.

Example 2: Create a PDF with default settings (using layout.ini)

python layout.py input.png output.pdf

This will use the settings in layout.ini to add bleed and create an imposition PDF.

Example 3: Create a PDF with a custom configuration file

python layout.py input.jpg output.pdf -c my_config.ini

This will use the settings in my_config.ini.

Example 4: No Bleed If bleed_size in the configuration is set to 0, no bleed is added, but imposition is still performed using the original image.

Configuration File (layout.ini)

The configuration file is a standard .ini file with two sections: Bleed and Imposition.

[Bleed]
bleed_size = 30            ; Size of the bleed in pixels
crop_mark_length = 20      ; Length of the crop marks in pixels
crop_mark_color = inverted ; Color of the crop marks (name of color or 'inverted')
bleed_mode = repeat        ; Method for adding bleed (repeat or mirror)
cut_mark_length = 50       ; Length of cut lines, in pixels

[Imposition]
paper_size = letter        ; Paper size (e.g., letter, a4, legal)
background_color = white    ; Background color for the Image and the PDF
orientation = portrait     ; Page orientation (portrait or landscape)
num_copies = 4             ; Number of copies to fit on the page
cut_marks = True           ; Whether to draw cut marks around each image
margin = 1                 ; Margin around the edge of the page in mm
spacing = 0                ; Spacing between images in mm
imposition_mark_length = 5 ; Length of the imposition cut marks in mm

• bleed_size: The width of the bleed area added to each side of the image, in pixels.
• crop_mark_length: The length of the crop marks that extend outside the bleed area, in pixels.
• crop_mark_color: The color of the crop marks. Can be a standard color name (e.g., "black", "red") or "inverted". "inverted" will dynamically invert the color of each pixel where a crop mark is drawn, making it visible on both light and dark backgrounds.
• bleed_mode: How the bleed area is filled. "repeat" extends the edge pixels outward. "mirror" reflects the edge pixels.
• cut_mark_length: Length of short lines that are drawn at the center of each edge inside the bleed area.
• paper_size: The paper size for the output PDF. Valid values are those defined in reportlab.lib.pagesizes (e.g., "letter", "a4", "legal", "a3", "a5", etc.). See the ReportLab documentation for a complete list.
• orientation: Page orientation: "portrait" or "landscape".
• num_copies: The desired number of copies of the image to fit on the page. The script attempts to find an optimal layout (rows and columns).
• cut_marks: Boolean (True or False) indicating whether to draw cut marks around each imposed image.
• margin: The margin around the entire page, in millimeters (mm).
• spacing: The spacing between the images on the page, in millimeters (mm).
• imposition_mark_length: The length of the cut marks drawn around each individual image on the imposed page, in millimeters (mm). This is separate from the crop_mark_length used for the bleed.

Notes

• The script uses Bresenham's line algorithm for drawing crop marks, ensuring accurate and efficient line drawing, even with "inverted" colors. When using PIL.ImageDraw.Draw.line I would get a weird off by one error and I couldn't draw inverted lines anyway.
• DPI is read from image metadata. Defaults to 72 dpi if not specified.