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Andras Schmelczer 2026-03-30 08:09:47 +01:00
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#!/usr/bin/env python3
"""
Dithering Comparison Tool for 6-Color E-Ink Display
Generates side-by-side comparisons of different dithering algorithms
to help select the best option for your images.
Usage:
python compare.py image.jpg # Compare all algorithms
python compare.py image.jpg -a floyd_steinberg atkinson # Compare specific
python compare.py image.jpg --grid # Generate grid comparison
python compare.py image.jpg --html # Generate HTML report
python compare.py --list # List available algorithms
"""
import argparse
import os
import sys
import time
from pathlib import Path
from typing import List, Optional
from PIL import Image
from dither_algorithms import (
DITHER_ALGORITHMS,
apply_dithering,
get_algorithm_names,
PALETTE_RGB,
)
# Display dimensions
DISPLAY_WIDTH = 800
DISPLAY_HEIGHT = 480
def prepare_image(image_path: str, orientation: int = 0) -> Image.Image:
"""Load and prepare image for the display dimensions."""
img = Image.open(image_path).convert('RGB')
# Apply rotation
if orientation == 90:
img = img.transpose(Image.Transpose.ROTATE_270)
elif orientation == 180:
img = img.transpose(Image.Transpose.ROTATE_180)
elif orientation == 270:
img = img.transpose(Image.Transpose.ROTATE_90)
# Calculate scaling to fit display
target_w, target_h = DISPLAY_WIDTH, DISPLAY_HEIGHT
scale = min(target_w / img.width, target_h / img.height)
new_w = int(img.width * scale)
new_h = int(img.height * scale)
# Resize with high-quality resampling
img = img.resize((new_w, new_h), Image.Resampling.LANCZOS)
# Center on white canvas
canvas = Image.new('RGB', (target_w, target_h), (255, 255, 255))
x = (target_w - new_w) // 2
y = (target_h - new_h) // 2
canvas.paste(img, (x, y))
return canvas
def run_comparison(
image_path: str,
algorithms: Optional[List[str]] = None,
output_dir: str = 'dither_output',
orientation: int = 0,
) -> dict:
"""
Run dithering comparison and save results.
Returns dict with algorithm names as keys and tuples of (output_path, duration) as values.
"""
if algorithms is None:
algorithms = get_algorithm_names()
# Prepare output directory
output_path = Path(output_dir)
output_path.mkdir(parents=True, exist_ok=True)
# Get base name for outputs
base_name = Path(image_path).stem
# Load and prepare source image
print(f"Loading and preparing: {image_path}")
source = prepare_image(image_path, orientation)
# Save prepared source for reference
source_out = output_path / f"{base_name}_source.png"
source.save(source_out)
print(f" Saved prepared source: {source_out}")
results = {}
for algo_name in algorithms:
if algo_name not in DITHER_ALGORITHMS:
print(f" Warning: Unknown algorithm '{algo_name}', skipping")
continue
algo_info = DITHER_ALGORITHMS[algo_name]
print(f" Processing: {algo_info['name']}...", end=' ', flush=True)
start_time = time.time()
dithered = apply_dithering(source, algo_name)
duration = time.time() - start_time
out_file = output_path / f"{base_name}_{algo_name}.png"
dithered.save(out_file)
results[algo_name] = (str(out_file), duration)
print(f"{duration:.2f}s -> {out_file}")
return results
def create_comparison_grid(
image_path: str,
algorithms: Optional[List[str]] = None,
output_dir: str = 'dither_output',
orientation: int = 0,
cols: int = 3,
) -> str:
"""Create a single image with all algorithms in a grid layout."""
if algorithms is None:
algorithms = get_algorithm_names()
output_path = Path(output_dir)
output_path.mkdir(parents=True, exist_ok=True)
base_name = Path(image_path).stem
source = prepare_image(image_path, orientation)
# Calculate grid dimensions
n_images = len(algorithms) + 1 # +1 for source
rows = (n_images + cols - 1) // cols
# Thumbnail size (scaled down for grid)
thumb_w = DISPLAY_WIDTH // 2
thumb_h = DISPLAY_HEIGHT // 2
padding = 10
label_height = 30
# Create grid canvas
grid_w = cols * (thumb_w + padding) + padding
grid_h = rows * (thumb_h + label_height + padding) + padding
grid = Image.new('RGB', (grid_w, grid_h), (240, 240, 240))
# Import for text rendering
try:
from PIL import ImageDraw, ImageFont
draw = ImageDraw.Draw(grid)
try:
font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 16)
except:
font = ImageFont.load_default()
except ImportError:
draw = None
font = None
def add_to_grid(img: Image.Image, label: str, idx: int):
row = idx // cols
col = idx % cols
x = padding + col * (thumb_w + padding)
y = padding + row * (thumb_h + label_height + padding)
# Resize for thumbnail
thumb = img.resize((thumb_w, thumb_h), Image.Resampling.LANCZOS)
grid.paste(thumb, (x, y + label_height))
# Add label
if draw:
draw.text((x + 5, y + 5), label, fill=(0, 0, 0), font=font)
# Add source image first
add_to_grid(source, "Original (Prepared)", 0)
# Process and add each algorithm
for i, algo_name in enumerate(algorithms, 1):
if algo_name not in DITHER_ALGORITHMS:
continue
algo_info = DITHER_ALGORITHMS[algo_name]
print(f" Grid: {algo_info['name']}...")
dithered = apply_dithering(source, algo_name)
add_to_grid(dithered, algo_info['name'], i)
# Save grid
grid_file = output_path / f"{base_name}_grid.png"
grid.save(grid_file)
print(f"Grid saved: {grid_file}")
return str(grid_file)
def create_side_by_side(
image_path: str,
algo1: str,
algo2: str,
output_dir: str = 'dither_output',
orientation: int = 0,
) -> str:
"""Create a side-by-side comparison of two algorithms."""
output_path = Path(output_dir)
output_path.mkdir(parents=True, exist_ok=True)
base_name = Path(image_path).stem
source = prepare_image(image_path, orientation)
info1 = DITHER_ALGORITHMS[algo1]
info2 = DITHER_ALGORITHMS[algo2]
print(f" Processing {info1['name']}...")
img1 = apply_dithering(source, algo1)
print(f" Processing {info2['name']}...")
img2 = apply_dithering(source, algo2)
# Create side-by-side
padding = 20
label_h = 40
width = DISPLAY_WIDTH * 2 + padding * 3
height = DISPLAY_HEIGHT + padding * 2 + label_h
canvas = Image.new('RGB', (width, height), (240, 240, 240))
canvas.paste(img1, (padding, padding + label_h))
canvas.paste(img2, (DISPLAY_WIDTH + padding * 2, padding + label_h))
# Add labels
try:
from PIL import ImageDraw, ImageFont
draw = ImageDraw.Draw(canvas)
try:
font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 20)
except:
font = ImageFont.load_default()
draw.text((padding + 10, padding + 5), info1['name'], fill=(0, 0, 0), font=font)
draw.text((DISPLAY_WIDTH + padding * 2 + 10, padding + 5), info2['name'], fill=(0, 0, 0), font=font)
except ImportError:
pass
out_file = output_path / f"{base_name}_{algo1}_vs_{algo2}.png"
canvas.save(out_file)
print(f"Side-by-side saved: {out_file}")
return str(out_file)
def generate_html_report(
image_path: str,
results: dict,
output_dir: str = 'dither_output',
) -> str:
"""Generate an HTML report for easy comparison."""
output_path = Path(output_dir)
base_name = Path(image_path).stem
html = f"""<!DOCTYPE html>
<html>
<head>
<title>Dithering Comparison: {base_name}</title>
<style>
body {{
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
background: #1a1a2e;
color: #eee;
margin: 0;
padding: 20px;
}}
h1 {{ color: #00d9ff; margin-bottom: 10px; }}
.subtitle {{ color: #888; margin-bottom: 30px; }}
.grid {{
display: grid;
grid-template-columns: repeat(auto-fill, minmax(420px, 1fr));
gap: 20px;
}}
.card {{
background: #16213e;
border-radius: 12px;
overflow: hidden;
box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}}
.card img {{
width: 100%;
height: auto;
display: block;
cursor: pointer;
transition: transform 0.2s;
}}
.card img:hover {{ transform: scale(1.02); }}
.card-info {{
padding: 15px;
}}
.card-title {{
font-size: 18px;
font-weight: 600;
color: #00d9ff;
margin-bottom: 5px;
}}
.card-desc {{
font-size: 13px;
color: #888;
margin-bottom: 8px;
}}
.card-time {{
font-size: 12px;
color: #666;
}}
.source-card {{
grid-column: 1 / -1;
max-width: 850px;
}}
.source-card img {{ max-width: 800px; }}
.palette {{
display: flex;
gap: 10px;
margin: 20px 0;
padding: 15px;
background: #16213e;
border-radius: 8px;
width: fit-content;
}}
.color-swatch {{
width: 40px;
height: 40px;
border-radius: 6px;
border: 2px solid #333;
}}
.fullscreen {{
display: none;
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 100%;
background: rgba(0,0,0,0.95);
z-index: 1000;
justify-content: center;
align-items: center;
}}
.fullscreen img {{
max-width: 95%;
max-height: 95%;
}}
.fullscreen.active {{ display: flex; }}
</style>
</head>
<body>
<h1>Dithering Algorithm Comparison</h1>
<p class="subtitle">Source: {image_path}</p>
<h3>6-Color Palette</h3>
<div class="palette">
"""
for i, (color, name) in enumerate(zip(PALETTE_RGB, ['Black', 'White', 'Yellow', 'Red', 'Blue', 'Green'])):
r, g, b = color
html += f' <div class="color-swatch" style="background: rgb({r},{g},{b});" title="{name}"></div>\n'
html += """ </div>
<h3>Results</h3>
<div class="grid">
<div class="card source-card">
<img src="{base_name}_source.png" alt="Prepared Source" onclick="showFullscreen(this)">
<div class="card-info">
<div class="card-title">Original (Prepared)</div>
<div class="card-desc">Source image resized to 800x480 with LANCZOS resampling</div>
</div>
</div>
"""
for algo_name, (out_path, duration) in results.items():
algo_info = DITHER_ALGORITHMS[algo_name]
filename = Path(out_path).name
html += f"""
<div class="card">
<img src="{filename}" alt="{algo_info['name']}" onclick="showFullscreen(this)">
<div class="card-info">
<div class="card-title">{algo_info['name']}</div>
<div class="card-desc">{algo_info['description']}</div>
<div class="card-time">Processing time: {duration:.2f}s</div>
</div>
</div>
"""
html += """
</div>
<div class="fullscreen" onclick="hideFullscreen()">
<img src="" id="fullscreen-img">
</div>
<script>
function showFullscreen(img) {
document.getElementById('fullscreen-img').src = img.src;
document.querySelector('.fullscreen').classList.add('active');
}
function hideFullscreen() {
document.querySelector('.fullscreen').classList.remove('active');
}
document.addEventListener('keydown', (e) => {
if (e.key === 'Escape') hideFullscreen();
});
</script>
</body>
</html>
"""
html_file = output_path / f"{base_name}_report.html"
html_file.write_text(html.replace('{base_name}', base_name))
print(f"HTML report saved: {html_file}")
return str(html_file)
def list_algorithms():
"""Print available algorithms with descriptions."""
print("\nAvailable Dithering Algorithms:")
print("=" * 70)
for name, info in DITHER_ALGORITHMS.items():
print(f"\n {name}")
print(f" Name: {info['name']}")
print(f" {info['description']}")
print()
def main():
parser = argparse.ArgumentParser(
description='Compare dithering algorithms for 6-color e-ink display',
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog="""
Examples:
python compare.py photo.jpg # Compare all algorithms
python compare.py photo.jpg -a atkinson pil_fs # Compare specific algorithms
python compare.py photo.jpg --grid # Generate grid comparison
python compare.py photo.jpg --html # Generate HTML report
python compare.py photo.jpg --side-by-side atkinson floyd_steinberg
python compare.py --list # List available algorithms
"""
)
parser.add_argument('image', nargs='?', help='Input image file')
parser.add_argument('-a', '--algorithms', nargs='+',
help='Specific algorithms to compare (default: all)')
parser.add_argument('-o', '--output', default='dither_output',
help='Output directory (default: dither_output)')
parser.add_argument('--orientation', '-r', type=int, default=0,
choices=[0, 90, 180, 270],
help='Rotate image (degrees)')
parser.add_argument('--grid', action='store_true',
help='Generate grid comparison image')
parser.add_argument('--html', action='store_true',
help='Generate HTML comparison report')
parser.add_argument('--side-by-side', nargs=2, metavar=('ALGO1', 'ALGO2'),
help='Create side-by-side comparison of two algorithms')
parser.add_argument('--list', action='store_true',
help='List available algorithms')
args = parser.parse_args()
if args.list:
list_algorithms()
return
if not args.image:
parser.error("Image file is required (unless using --list)")
if not os.path.exists(args.image):
print(f"Error: File not found: {args.image}")
sys.exit(1)
print(f"\n{'='*60}")
print(f"Dithering Comparison Test Suite")
print(f"{'='*60}\n")
if args.side_by_side:
create_side_by_side(
args.image,
args.side_by_side[0],
args.side_by_side[1],
args.output,
args.orientation
)
elif args.grid:
create_comparison_grid(
args.image,
args.algorithms,
args.output,
args.orientation
)
else:
results = run_comparison(
args.image,
args.algorithms,
args.output,
args.orientation
)
if args.html:
generate_html_report(args.image, results, args.output)
print(f"\n{'='*60}")
print(f"Done! Output saved to: {args.output}/")
print(f"{'='*60}\n")
if __name__ == '__main__':
main()