PDFtuning Manual/Wiki

1. What PDFtuning Is For

PDFtuning is designed to optimize PDFs in a new and simple way. It focuses on solving problems such as:

• PDFs having no outline/TOC, making long documents hard to navigate

• Large white margins around pages making the text area too small

• Academic papers and technical documents with multi‑column/complex layouts being hard to read on small screens

• Images looking washed out and low‑contrast on e‑ink displays

• PDF files being too large, taking up device storage and slowing down transfer

With modules like Smart Crop, Auto TOC/Outline generation, Reflow, and Compression, you can tailor each PDF to your specific device and reading style.

2. Interface Overview

When you open PDFtuning, the main window is roughly divided into four areas:

• Top toolbar

  • Switch UI language

  • Toggle light/dark theme

  • Open the Help menu (including the in‑app guide tour)

• Left: Device selection & page preview

  • Preview device list: a set of pre‑configured reader models; you can search by device name

  • Hide device frame checkbox: focus on page content only, without the device bezel

  • Preview area: shows either the original PDF or the optimized result

  • Floating navigation bar: buttons for First/Previous/Next/Last page, TOC, landscape preview, and crop preview

• Center: File list (card‑style file management)

  • Drag one or more PDFs into the window, or click the button to add files

  • Each PDF is shown as a card with the original file and its result

  • Cards display file name, size, modified date, and status (Pending / Done)

  • Actions include “Reveal in Finder”, “Send to…”, and “Remove from list”

• Right: Optimization modules & options

  • Tabs for:

    • Smart Crop

    • Image & Watermark

    • TOC Navigation

    • Reflow

    • Compression

  • Option groups below:

    • Crop Settings, Image Processing, TOC, Reflow, Compression, etc.

  • “Start Tuning” button at the bottom: generates an optimized PDF using the current settings

3. Getting Started (First‑Time Use)

1. Add PDFs to optimize

   • In the file list area, click the “Add PDF” button, or simply drag PDFs into the window.

   • A card will appear for each file: the left tag is the Original, the right tag is the Result (initially empty).

2. Choose a preview device

   • In the preview device list (top‑left), choose your e‑reader model or a device with similar resolution.

   • Pages in the preview area will be rendered to match the device’s screen size, so you can judge readability.

3. Choose the optimization modules you need

   • On the right side, go through the optimization modules:

     • Smart Crop: remove margins and fit the page to the screen

     • Image & Watermark: grayscale conversion, contrast enhancement, watermark removal

     • TOC Navigation: generate a PDF outline (TOC)

     • Reflow: turn multi‑column complex layouts into a single flowing text layout

     • Compression: reduce file size

   • Enable the modules you need; keep others disabled to avoid unnecessary processing.

4. Click “Start Tuning”

   • After selecting a file and adjusting options, click “Start Tuning” in the bottom‑right corner.

   • Progress will be shown on the file card; when it finishes, a new Result tag appears on the card.

5. Compare results in the device preview

   • Switch between “Original” and “Result” in the preview area to compare cropping, reflow, grayscale, etc.

   • Use the floating toolbar to turn pages, toggle landscape preview, and open the TOC.

6. Export and send

   • On the file card, click “Reveal in Finder” to locate the optimized file.

   • Use “Send to…” to pass the result to another app or a “Send to Kindle” workflow.

4. Smart Crop & Screen Fitting

The Smart Crop module automatically detects the content area of each page, removes white margins, and maximizes the effective reading area while handling headers and footers intelligently.

4.1 Key Options

• Enable Smart Crop

  • Enabled by default. Automatically detects the content area on each page and crops away the blank margins.

  • Only changes the visible CropBox; it does not alter the underlying text content.

• Smart header/footer detection

  • Attempts to detect repeating headers and footers that appear on every page and prevent them from expanding the crop area.

  • Very useful for papers and reports that have fixed headers/footers, increasing the body text area.

• Unify crop area

  • All pages unified: computes one global crop box for the entire document so all pages share the same view; this avoids boundary “jumping” when turning pages.

  • Mirror odd/even pages: computes separate unified boxes for odd and even pages, useful for books with asymmetric left/right margins.

  • With unification enabled, some pages may waste a bit of space, but paging feels smoother.

• Margins (px)

  • Extra pixel margins preserved outside the detected content area to avoid cutting off footnotes, page numbers, etc.

  • Higher values are more conservative; values that are too small may trim real content.

• Detection mode: Text / Pixel

  • Text mode (default): uses PDF text blocks to infer content boundaries. Fast and suitable for most text‑based documents.

  • Pixel mode: rasterizes the page and looks for non‑white pixels to detect content, better for scanned or image‑based PDFs, but slower.

• Scale to screen

  • Crops pages to match the selected device’s screen width and height as closely as possible, keeping the page centered.

  • Currently implemented as cropping rather than geometric scaling, which helps preserve text sharpness.

4.2 Usage Tips

• Academic papers / white papers

  • Recommended: enable Smart Crop + smart header/footer detection, and slightly increase margins (e.g., 10–20 px).

  • If page boundaries “jump” noticeably when turning pages, enable Unify Crop Area.

• Scanned books / image‑based PDFs

  • Recommended: switch detection mode to Pixel, then fine‑tune margins.

  • If scan quality is poor, keep a bit more margin for safety.

5. Image & Watermark Module (Grayscale, Contrast, Watermarks)

This module optimizes images for e‑ink displays and attempts to remove common background watermarks.

5.1 Key Options

• Grayscale (E‑Ink 256 levels)

  • Rasterizes pages to grayscale images and outputs an image‑based PDF.

  • Matches the grayscale rendering of e‑ink screens and can make text appear smoother; final size depends on compression settings.

• Enhance contrast

  • Increases contrast on grayscale images so text appears darker and more legible.

  • A typical contrast factor is between 1.1–1.8; overly high values may lose detail (thin lines, dark areas in photos).

• Remove watermark

  • Tries to remove background watermarks, slanted light text, and other distractions.

  • For text‑based PDFs, it prefers cleaning watermark objects structurally; for scans, it may resort to image processing.

  • Higher “strength” removes more aggressively; if set too high, some fine details may be affected, so always verify in the preview.

5.2 Usage Tips

• For technical documents on e‑ink readers:

  • Enable Grayscale + Enhance contrast, and moderately enable Remove watermark.

  • After processing, compare Original vs Result in the device preview and adjust strengths if needed.

• For PPTs or textbooks with many color diagrams:

  • Grayscale will change color contrast relationships. Test a sample first and confirm that important annotations remain readable.

6. TOC Navigation (Outline)

The TOC Navigation module automatically analyzes headings in the PDF and writes them into the PDF’s outline (TOC), making long documents much easier to navigate on e‑readers.

6.1 Key Options

• Generate PDF outline

  • When enabled, the optimization pipeline will detect headings and write them as the PDF outline.

  • Most e‑readers surface these entries in the Table of Contents / Outline view.

• Outline depth

  • Controls how many heading levels to include (e.g., 1 / 2 / 3 levels).

  • Deeper outlines create more entries but provide finer‑grained navigation.

• Outline preview

  • Before running optimization, you can preview detected headings to check for obvious false positives or missing entries.

  • If you see “No usable headings detected”, the PDF is likely scanned or has irregular structure.

6.2 Usage Tips

• Great for paper collections, technical books, and conference slide decks.

• If the original PDF already has a good outline, you can turn this module off and only use crop/compression.

• For heavily irregular layouts (image‑heavy, inconsistent heading styles), automatic TOC quality may be limited.

7. Reflow (Layout Re‑arrangement)

The Reflow module converts multi‑column or complex layouts into a single flowing text layout that is easier to read on 6–8 inch e‑readers.

7.1 Key Options

• Enable smart reflow

  • Extracts reflowable text from the PDF and re‑lays it out as a single‑column flowing text document.

  • Handles common structures such as multi‑column layouts, footnotes, and some TOC pages.

• Generate flowing text only (no images)

  • Ignores all images and keeps text only.

  • Ideal when you mainly care about reading text (e.g., close reading of a paper) and want faster performance and smaller files.

• Reflow limitations

  • Scanned or fully image‑based PDFs cannot be reflowed; such files can still benefit from Smart Crop, Grayscale, and Compression.

7.2 Usage Tips

• Recommended to enable reflow for:

  • Long papers, technical reports, multi‑column magazines, and white papers.

  • PDFs where the font size is so small that you must constantly zoom in.

• Not recommended for:

  • Documents whose meaning relies heavily on complex spatial layout (posters, layout‑driven art books).

  • Simple single‑column PDFs that already read fine after basic cropping.

8. Compression & Cleanup

The Compression module focuses on reducing PDF size while preserving readability as much as possible.

8.1 Key Options

• Image quality (High / Standard / Low)

  • High: preserves as much detail as possible; larger file size.

  • Standard: balances visual quality and size; suitable for most documents.

  • Low: more aggressive compression, suitable when image quality is not critical and storage is the priority.

• Optimize embedded images only

  • Downsamples and recompresses embedded images according to a target DPI.

  • Does not convert text‑only pages into images. Pure text PDFs may not shrink much.

• Remove hidden/embedded objects

  • Cleans metadata, JavaScript, attachments/embedded files, thumbnails, and other non‑essential content.

  • Further reduces file size and lowers potential security risks.

• Optimize fonts

  • Subsets fonts and removes unused glyph data.

  • The implementation is conservative: it avoids removing fonts that are actually used, to prevent display issues.

8.2 Usage Tips

• When uploading to cloud services or transferring files via email/wireless:

  • Choose Standard or Low image quality and enable “Remove hidden objects” and “Optimize fonts”.

  • For documents with many high‑resolution images, compare key diagrams before/after compression.

9. Page Orientation & Landscape Preview

• Landscape preview button

  • In the floating preview toolbar, toggle landscape mode to simulate holding your device horizontally.

  • Especially useful for wide content such as PPT decks and 16:9 slides.

• Page rotation

  • For PDFs scanned in a rotated orientation (90°/180°), rotation can be applied during optimization.

  • Combine this with landscape preview to find the most comfortable reading orientation on your device.

10. File Management & Task History

• Card‑style file list

  • Original and Result files are shown together on one card for easy comparison and management.

  • Removing a card from the list will not delete the actual file from disk.

• Task status & history

  • Each optimization run is tagged with a status (Pending / Done) and history count.

  • You can generate multiple results from the same source PDF with different settings and compare them.

• Open / Send actions

  • Reveal in Finder: show the file in Finder.

  • Send to…: hand off the file to another app or system share target (e.g., a “Send to Kindle” workflow).

11. Common Issues & Hints

• “No reflowable text found”

  • Usually means the PDF is scanned or image‑based and cannot be reflowed.

  • In this case, use Smart Crop, Grayscale, and Compression instead.

• “No usable headings detected” or empty TOC

  • The document may have no clear heading styles, or it may be purely images.

  • You can still use Crop/Reflow without forcing TOC generation.

• File size change is minimal

  • For pure text PDFs or already heavily compressed images, there may be little room for further compression.

  • Try lowering image quality or enabling Grayscale/Reflow‑text‑only where appropriate.

• Reader shows errors or displays the result incorrectly

  • Reduce compression strength (increase image quality, disable extreme compression options).

  • If problems persist, regenerate from the original file with more conservative settings.

12. Recommended Combinations (Examples)

• Reading English papers on a 6–7" Kindle

  • Select the corresponding Kindle model in the preview device list.

  • Enable Smart Crop + smart header/footer detection.

  • Enable TOC Navigation with 1–2 outline levels to quickly jump between sections and revisit highlighted positions.

  • Enable Reflow, optionally with “text‑only” mode for close reading and annotation.

  • Apply moderate image compression and avoid overly aggressive watermark removal.

• Reading scanned books (Chinese/English)

  • Set detection mode to Pixel and keep margins slightly larger.

  • Enable Grayscale + moderate Contrast enhancement.

  • Disable Reflow and TOC generation (usually ineffective for scans).

  • Use Standard image quality for compression.

• Presenting PPT/handouts on a tablet

  • Keep Reflow disabled to preserve the original slide layout.

  • Lightly crop margins and fit pages to the target device screen.

  • Optionally enable TOC Navigation so you can jump to key sections or backup slides during a talk.

  • Apply moderate image compression to make sharing and syncing easier.

• Organizing long technical books/tutorials for multi‑device reading

  • Choose both your primary e‑reader and a tablet in the preview device list to check layouts.

  • Enable Smart Crop and Unify Crop Area so page boundaries remain stable when paging.

  • Enable TOC Navigation with 2–3 outline levels to make cross‑chapter jumps and “resume where I left off” seamless across devices.

  • Apply moderate image compression and enable font optimization to reduce size while remaining readable, making cloud sync and multi‑device use more convenient.

By combining these modules and options, you can tailor PDFs for different devices and document types. When trying new settings, make full use of the device preview on the left to compare Original vs Result and find the best balance among readability, page count, and file size.