OptimPDF

OptimPDF is a tool to optimize image-based PDFs, where each page consists of a single image, for handheld devices. It also can convert ZIPed image files to PDF.

Subcommands

The following subcommands are accepted.

reduce

• Shrink an image in a PDF so that the number of pixels in the PDF fits exactly into the specified size.
• Images that are originally smaller than the specified size will keep their original size and will not be enlarged.
• Portrait images will be reduced to the exact number of pixels when the device is placed vertically, and landscape images will be reduced to the exact number of pixels when the device is placed horizontally.
• Images smaller than the specified threshold will be scaled down to fit as a double-page view on the device.
• It also can lighten the color of paper burn. However, this may cause the light shading colors to disappear as well.

rotate

• Aligns each page of a PDF to the specified angle (0, 90, 180, or 270) of rotation.
• You can also specify a reference PDF and align the direction of rotation of each page of that PDF. This is useful, for example, to restore pages that have been rotated by Adobe Acrobat's OCR.

unzip

• Extracts only the image files from the ZIP file and creates a PDF with a single page consisting of a single image.
• You can also specify that the PDF should be right-open.
• The output is sorted by path in the ZIP.

How to start

1. Install Java (11 or later) and ImageMagick (6 or later).

2. Download optimpdf-2.0.0-jar-with-dependencies.jar from the Release page.

3. Execute the JAR from the command line, specifying the subcommand and target file(s) as arguments.

   java -jar optimpdf-2.0.0-jar-with-dependencies.jar reduce some.pdf

Specifying input and output

Specifying input files

• Specify an input file to be processed by a command line argument.
• You can specify multiple files to be processed.
• With the -r, --recursive option, if the target is a directory, files in the directory are processed recursively.

Specifying output files

• Without any options, it will try to output the result of processing to the same path as the input file and will fail to overwrite it.
• With the -f, --force option, the output file will be overwritten even if it already exists.
• The -o, --outfile option allows you to specify the name of the output file. It can be used only when there is only one input file.
• The -s, --suffix option can be used to specify a suffix to append to the input filename.
• The -d, --outdir option can be used to specify a directory to output files to.
• The -u, --update option allows you to process only those files whose output file does not exist or whose input file is newer than the output file.

Command-Line Options

Top-level Options

Option	Description
-h, --help	Show help message and exit.
-V, --version	Print version information and exit.

Options common to all subcommands

Option	Description
-d, --outdir=dir	Write destination files to dir.
-f, --force	Overwrite destination files.
-h, --help	Show help message and exit.
-l, --list	Show the list of files to be processed and exit.
-n, --dry-run	Dry run (skip saving destination files).
-o, --outfile=file	Write output to file. For single input only.
-q, --quiet	Suppress displaying info on each page.
-r, --recursive	Process recursively.
-s, --suffix=suffix	Use source file name + suffix as destination file name.
-u, --update	Process only when the source is newer than the destination or when the destination is missing.

Options for reduce subcommand

Option	Description
-B, --bleach-pages=pages	Bleach specified pages. (eg: 1,3-5 or all)
-P, --pages=pages	Process specified pages only. (eg: 1,3-5)
-Q, --jpeg-quality=jpegQuality	Set JPEG quality. (Default: 50)
-S, --screen-size=screenSize	Set output screen size. (Default: 1536x2048)
-T, --number-of-threads=numberOfThreads	Set number of threads to use. (Default: 8)
-W, --double-page-threshold=doublePageThreshold	Set double-page size threshold. Halve output screen size if the source JPEG is smaller than this. (Default: 2539)

Options for rotate subcommand

Option	Description
-D, --degree=degree	Set all page's rotation to the degree. Must be one of 0, 90, 180, or 270. (Default: 0)
-R, --ref-pdf=pdf	Match the rotation of each page to the referenced pdf file.

Options for unzip subcommand

Option	Description
-R, --right-to-left	Set direction to right-to-left.

How to build

Install Git, Java (11 or later), Maven, and ImageMagick (6 or later), then clone & build.

git clone https://github.com/alpha3166/optimpdf
cd optimpdf
mvn package