Thumbnail

#!/usr/bin/env python3 """ Create thumbnail grids from PowerPoint presentation slides.

Creates a grid layout of slide thumbnails with configurable columns (max 6). Each grid contains up to cols×(cols+1) images. For presentations with more slides, multiple numbered grid files are created automatically.

The program outputs the names of all files created.

Output:

• Single grid: {prefix}.jpg (if slides fit in one grid)
• Multiple grids: {prefix}-1.jpg, {prefix}-2.jpg, etc.

Grid limits by column count:

• 3 cols: max 12 slides per grid (3×4)
• 4 cols: max 20 slides per grid (4×5)
• 5 cols: max 30 slides per grid (5×6) [default]
• 6 cols: max 42 slides per grid (6×7)

Usage: python thumbnail.py input.pptx [output_prefix] [--cols N] [--outline-placeholders]

Examples: python thumbnail.py presentation.pptx # Creates: thumbnails.jpg (using default prefix) # Outputs: # Created 1 grid(s): # - thumbnails.jpg

python thumbnail.py large-deck.pptx grid --cols 4
# Creates: grid-1.jpg, grid-2.jpg, grid-3.jpg
# Outputs:
#   Created 3 grid(s):
#     - grid-1.jpg
#     - grid-2.jpg
#     - grid-3.jpg

python thumbnail.py template.pptx analysis --outline-placeholders
# Creates thumbnail grids with red outlines around text placeholders

"""

import argparse import subprocess import sys import tempfile from pathlib import Path

from inventory import extract_text_inventory from PIL import Image, ImageDraw, ImageFont from pptx import Presentation

Constants

THUMBNAIL_WIDTH = 300 # Fixed thumbnail width in pixels CONVERSION_DPI = 100 # DPI for PDF to image conversion MAX_COLS = 6 # Maximum number of columns DEFAULT_COLS = 5 # Default number of columns JPEG_QUALITY = 95 # JPEG compression quality

Grid layout constants

GRID_PADDING = 20 # Padding between thumbnails BORDER_WIDTH = 2 # Border width around thumbnails FONT_SIZE_RATIO = 0.12 # Font size as fraction of thumbnail width LABEL_PADDING_RATIO = 0.4 # Label padding as fraction of font size

def main(): parser = argparse.ArgumentParser( description="Create thumbnail grids from PowerPoint slides." ) parser.add_argument("input", help="Input PowerPoint file (.pptx)") parser.add_argument( "output_prefix", nargs="?", default="thumbnails", help="Output prefix for image files (default: thumbnails, will create prefix.jpg or prefix-N.jpg)", ) parser.add_argument( "--cols", type=int, default=DEFAULT_COLS, help=f"Number of columns (default: {DEFAULT_COLS}, max: {MAX_COLS})", ) parser.add_argument( "--outline-placeholders", action="store_true", help="Outline text placeholders with a colored border", )

args = parser.parse_args()

# Validate columns
cols = min(args.cols, MAX_COLS)
if args.cols > MAX_COLS:
    print(f"Warning: Columns limited to {MAX_COLS} (requested {args.cols})")

# Validate input
input_path = Path(args.input)
if not input_path.exists() or input_path.suffix.lower() != ".pptx":
    print(f"Error: Invalid PowerPoint file: {args.input}")
    sys.exit(1)

# Construct output path (always JPG)
output_path = Path(f"{args.output_prefix}.jpg")

print(f"Processing: {args.input}")

try:
    with tempfile.TemporaryDirectory() as temp_dir:
        # Get placeholder regions if outlining is enabled
        placeholder_regions = None
        slide_dimensions = None
        if args.outline_placeholders:
            print("Extracting placeholder regions...")
            placeholder_regions, slide_dimensions = get_placeholder_regions(
                input_path
            )
            if placeholder_regions:
                print(f"Found placeholders on {len(placeholder_regions)} slides")

        # Convert slides to images
        slide_images = convert_to_images(input_path, Path(temp_dir), CONVERSION_DPI)
        if not slide_images:
            print("Error: No slides found")
            sys.exit(1)

        print(f"Found {len(slide_images)} slides")

        # Create grids (max cols×(cols+1) images per grid)
        grid_files = create_grids(
            slide_images,
            cols,
            THUMBNAIL_WIDTH,
            output_path,
            placeholder_regions,
            slide_dimensions,
        )

        # Print saved files
        print(f"Created {len(grid_files)} grid(s):")
        for grid_file in grid_files:
            print(f"  - {grid_file}")

except Exception as e:
    print(f"Error: {e}")
    sys.exit(1)

def create_hidden_slide_placeholder(size): """Create placeholder image for hidden slides.""" img = Image.new("RGB", size, color="#F0F0F0") draw = ImageDraw.Draw(img) line_width = max(5, min(size) // 100) draw.line([(0, 0), size], fill="#CCCCCC", width=line_width) draw.line([(size[0], 0), (0, size[1])], fill="#CCCCCC", width=line_width) return img

def get_placeholder_regions(pptx_path): """Extract ALL text regions from the presentation.

Returns a tuple of (placeholder_regions, slide_dimensions).
text_regions is a dict mapping slide indices to lists of text regions.
Each region is a dict with 'left', 'top', 'width', 'height' in inches.
slide_dimensions is a tuple of (width_inches, height_inches).
"""
prs = Presentation(str(pptx_path))
inventory = extract_text_inventory(pptx_path, prs)
placeholder_regions = {}

# Get actual slide dimensions in inches (EMU to inches conversion)
slide_width_inches = (prs.slide_width or 9144000) / 914400.0
slide_height_inches = (prs.slide_height or 5143500) / 914400.0

for slide_key, shapes in inventory.items():
    # Extract slide index from "slide-N" format
    slide_idx = int(slide_key.split("-")[1])
    regions = []

    for shape_key, shape_data in shapes.items():
        # The inventory only contains shapes with text, so all shapes should be highlighted
        regions.append(
            {
                "left": shape_data.left,
                "top": shape_data.top,
                "width": shape_data.width,
                "height": shape_data.height,
            }
        )

    if regions:
        placeholder_regions[slide_idx] = regions

return placeholder_regions, (slide_width_inches, slide_height_inches)

def convert_to_images(pptx_path, temp_dir, dpi): """Convert PowerPoint to images via PDF, handling hidden slides.""" # Detect hidden slides print("Analyzing presentation...") prs = Presentation(str(pptx_path)) total_slides = len(prs.slides)

# Find hidden slides (1-based indexing for display)
hidden_slides = {
    idx + 1
    for idx, slide in enumerate(prs.slides)
    if slide.element.get("show") == "0"
}

print(f"Total slides: {total_slides}")
if hidden_slides:
    print(f"Hidden slides: {sorted(hidden_slides)}")

pdf_path = temp_dir / f"{pptx_path.stem}.pdf"

# Convert to PDF
print("Converting to PDF...")
result = subprocess.run(
    [
        "soffice",
        "--headless",
        "--convert-to",
        "pdf",
        "--outdir",
        str(temp_dir),
        str(pptx_path),
    ],
    capture_output=True,
    text=True,
)
if result.returncode != 0 or not pdf_path.exists():
    raise RuntimeError("PDF conversion failed")

# Convert PDF to images
print(f"Converting to images at {dpi} DPI...")
result = subprocess.run(
    ["pdftoppm", "-jpeg", "-r", str(dpi), str(pdf_path), str(temp_dir / "slide")],
    capture_output=True,
    text=True,
)
if result.returncode != 0:
    raise RuntimeError("Image conversion failed")

visible_images = sorted(temp_dir.glob("slide-*.jpg"))

# Create full list with placeholders for hidden slides
all_images = []
visible_idx = 0

# Get placeholder dimensions from first visible slide
if visible_images:
    with Image.open(visible_images[0]) as img:
        placeholder_size = img.size
else:
    placeholder_size = (1920, 1080)

for slide_num in range(1, total_slides + 1):
    if slide_num in hidden_slides:
        # Create placeholder image for hidden slide
        placeholder_path = temp_dir / f"hidden-{slide_num:03d}.jpg"
        placeholder_img = create_hidden_slide_placeholder(placeholder_size)
        placeholder_img.save(placeholder_path, "JPEG")
        all_images.append(placeholder_path)
    else:
        # Use the actual visible slide image
        if visible_idx < len(visible_images):
            all_images.append(visible_images[visible_idx])
            visible_idx += 1

return all_images

def create_grids( image_paths, cols, width, output_path, placeholder_regions=None, slide_dimensions=None, ): """Create multiple thumbnail grids from slide images, max cols×(cols+1) images per grid.""" # Maximum images per grid is cols × (cols + 1) for better proportions max_images_per_grid = cols * (cols + 1) grid_files = []

print(
    f"Creating grids with {cols} columns (max {max_images_per_grid} images per grid)"
)

# Split images into chunks
for chunk_idx, start_idx in enumerate(
    range(0, len(image_paths), max_images_per_grid)
):
    end_idx = min(start_idx + max_images_per_grid, len(image_paths))
    chunk_images = image_paths[start_idx:end_idx]

    # Create grid for this chunk
    grid = create_grid(
        chunk_images, cols, width, start_idx, placeholder_regions, slide_dimensions
    )

    # Generate output filename
    if len(image_paths) <= max_images_per_grid:
        # Single grid - use base filename without suffix
        grid_filename = output_path
    else:
        # Multiple grids - insert index before extension with dash
        stem = output_path.stem
        suffix = output_path.suffix
        grid_filename = output_path.parent / f"{stem}-{chunk_idx + 1}{suffix}"

    # Save grid
    grid_filename.parent.mkdir(parents=True, exist_ok=True)
    grid.save(str(grid_filename), quality=JPEG_QUALITY)
    grid_files.append(str(grid_filename))

return grid_files

def create_grid( image_paths, cols, width, start_slide_num=0, placeholder_regions=None, slide_dimensions=None, ): """Create thumbnail grid from slide images with optional placeholder outlining.""" font_size = int(width * FONT_SIZE_RATIO) label_padding = int(font_size * LABEL_PADDING_RATIO)

# Get dimensions
with Image.open(image_paths[0]) as img:
    aspect = img.height / img.width
height = int(width * aspect)

# Calculate grid size
rows = (len(image_paths) + cols - 1) // cols
grid_w = cols * width + (cols + 1) * GRID_PADDING
grid_h = rows * (height + font_size + label_padding * 2) + (rows + 1) * GRID_PADDING

# Create grid
grid = Image.new("RGB", (grid_w, grid_h), "white")
draw = ImageDraw.Draw(grid)

# Load font with size based on thumbnail width
try:
    # Use Pillow's default font with size
    font = ImageFont.load_default(size=font_size)
except Exception:
    # Fall back to basic default font if size parameter not supported
    font = ImageFont.load_default()

# Place thumbnails
for i, img_path in enumerate(image_paths):
    row, col = i // cols, i % cols
    x = col * width + (col + 1) * GRID_PADDING
    y_base = (
        row * (height + font_size + label_padding * 2) + (row + 1) * GRID_PADDING
    )

    # Add label with actual slide number
    label = f"{start_slide_num + i}"
    bbox = draw.textbbox((0, 0), label, font=font)
    text_w = bbox[2] - bbox[0]
    draw.text(
        (x + (width - text_w) // 2, y_base + label_padding),
        label,
        fill="black",
        font=font,
    )

    # Add thumbnail below label with proportional spacing
    y_thumbnail = y_base + label_padding + font_size + label_padding

    with Image.open(img_path) as img:
        # Get original dimensions before thumbnail
        orig_w, orig_h = img.size

        # Apply placeholder outlines if enabled
        if placeholder_regions and (start_slide_num + i) in placeholder_regions:
            # Convert to RGBA for transparency support
            if img.mode != "RGBA":
                img = img.convert("RGBA")

            # Get the regions for this slide
            regions = placeholder_regions[start_slide_num + i]

            # Calculate scale factors using actual slide dimensions
            if slide_dimensions:
                slide_width_inches, slide_height_inches = slide_dimensions
            else:
                # Fallback: estimate from image size at CONVERSION_DPI
                slide_width_inches = orig_w / CONVERSION_DPI
                slide_height_inches = orig_h / CONVERSION_DPI

            x_scale = orig_w / slide_width_inches
            y_scale = orig_h / slide_height_inches

            # Create a highlight overlay
            overlay = Image.new("RGBA", img.size, (255, 255, 255, 0))
            overlay_draw = ImageDraw.Draw(overlay)

            # Highlight each placeholder region
            for region in regions:
                # Convert from inches to pixels in the original image
                px_left = int(region["left"] * x_scale)
                px_top = int(region["top"] * y_scale)
                px_width = int(region["width"] * x_scale)
                px_height = int(region["height"] * y_scale)

                # Draw highlight outline with red color and thick stroke
                # Using a bright red outline instead of fill
                stroke_width = max(
                    5, min(orig_w, orig_h) // 150
                )  # Thicker proportional stroke width
                overlay_draw.rectangle(
                    [(px_left, px_top), (px_left + px_width, px_top + px_height)],
                    outline=(255, 0, 0, 255),  # Bright red, fully opaque
                    width=stroke_width,
                )

            # Composite the overlay onto the image using alpha blending
            img = Image.alpha_composite(img, overlay)
            # Convert back to RGB for JPEG saving
            img = img.convert("RGB")

        img.thumbnail((width, height), Image.Resampling.LANCZOS)
        w, h = img.size
        tx = x + (width - w) // 2
        ty = y_thumbnail + (height - h) // 2
        grid.paste(img, (tx, ty))

        # Add border
        if BORDER_WIDTH > 0:
            draw.rectangle(
                [
                    (tx - BORDER_WIDTH, ty - BORDER_WIDTH),
                    (tx + w + BORDER_WIDTH - 1, ty + h + BORDER_WIDTH - 1),
                ],
                outline="gray",
                width=BORDER_WIDTH,
            )

return grid

if name == "main": main()