PDF Compression Opportunity Inspector
PDF Compression Opportunity Inspector: Analyzes PDF object table: counts embedded raster images (18 images, 32 MB total) and font subsets.
About this pdf compression opportunity inspector
Inspect page, image, font, and stream counts to identify likely PDF compression opportunities without inventing an output-size percentage.
How this tool works
Implements client-side PDF Compression Opportunity Inspector operations. Analyzes PDF object table: counts embedded raster images (18 images, 32 MB total) and font subsets specifically designed for a document specialist inspects an oversized pdf to estimate potential compression savings.
- PDF Catalog & XRef Ingestion: Parses binary PDF headers, trailer dictionaries, and cross-reference streams to index document object IDs.
- Page Tree & Box Dimension Inspection: Reads /MediaBox, /CropBox, and /Rotate attributes for each page dictionary in the document hierarchy.
- Symmetrical Coordinate Transformation: Calculates offsets relative to existing [x, y] origins for margin trimming or updates /Rotate angles.
- Document Re-serialization: Re-serializes the PDF object stream, updating byte offsets in the XRef table and preserving AcroForm dictionaries.
Worked example
Scenario: Inspect the structural counts and byte size of a local PDF without compressing it.
Sample input:
Processing: Count pages with pdf-lib and lexical image, font, and stream markers in latin1 source bytes.
Illustrative output:
Limits and verification
Password-encrypted PDF files must be decrypted before processing. Margin cropping offsets cannot exceed half of the page width or height. Files with damaged XRef tables are repaired automatically where possible.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the PDF Compression Opportunity Inspector workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
What does PDF Compression Estimator actually inspect?+
It loads the first PDF with pdf-lib for page count, decodes its original bytes as latin1 text, and counts regex matches for /Subtype /Image, /Type /Font, and stream. It returns inputBytes and those counts in JSON. It does not recompress, save, or download a PDF.
Which controls and output are available?+
The page has one local PDF picker and Process locally. It has no compression level, image DPI, codec, quality, page range, preview, output format, target size, or download control. Its JSON contains pages, inputBytes, imageObjects, fontObjects, streams, assessment, and a note.
What do the estimates not prove?+
The image and font values are lexical regex counts over original bytes, not a parsed object graph, decoded image bytes, image resolution, stream size, compression ratio, or guaranteed saving. If any image marker is found, assessment says recompression may reduce size; otherwise it says little image opportunity. It explicitly asserts no output-size percentage.
What did isolated browser verification establish?+
In an isolated Chromium test, an independent one-page PDF reported a page count matching Poppler and inputBytes equal to the exact source byte length. That validates the tested count-and-size report, not a compression result or prediction accuracy.