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Mustang1755 edited this page Sep 30, 2025 · 43 revisions

二外认为

When page images are stored as WebP in base64 format instead of PNG, the resulting PDF size is significantly reduced. If the images are called externally as WebP instead of embedding them as base64, the size is reduced by approximately 30% more. Below, I’m sharing an example BASH code block that converts PNGs to WebP and embeds the base64-encoded WebP images into all pages.

# Loop through all .png images in the specified directory (bg*.png)
for img in /path/to/your/directory/bg*.png; do

    # Extract the image filename without the extension (.png)
    img_name=$(basename "$img" .png)

    # Convert the .png image to .webp format with quality 75 and save it in the same directory
    convert "$img" -quality 75 "/path/to/your/directory/$img_name.webp"
done
# Set the folder path variable to the directory containing the images and other files
folder_path="/path/to/your/directory"

# Loop through all .page files in the specified folder
for file in "$folder_path"/*.page; do
  # Check if the file is a regular file (not a directory)
  if [[ -f "$file" ]]; then
    # Extract the src URL of the image in the .page file and replace the .png extension with .webp
    x=$(grep -oP 'src="\K[^"]+' $file | sed 's/\.png$//') && x="$x.webp"
    
    # Encode the .webp image file to base64 and save it to encode.txt
    base64 /path/to/your/directory/$x > /path/to/your/directory/encode.txt
    
    # Remove any newlines from the base64-encoded content and save to a temporary file
    cat /path/to/your/directory/encode.txt | tr -d '\n' > /path/to/your/directory/temp_base64.txt
    
    # Update the .page file to use the .webp extension instead of .png
    sed -i 's/\(src="[^"]*\)\.png"/\1.webp"/g' "$file"
    
    # Replace the image src in the .page file with the base64-encoded data URI for the .webp image
    awk -v x="$x" 'NR==FNR{base64=$0; next} {gsub(x, "data:image/webp;base64," base64)}1' \
        /path/to/your/directory/temp_base64.txt $file \
        > /path/to/your/directory/temp.page \
        && mv /path/to/your/directory/temp.page $file 
  fi
done
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