komopdf Feature Guide

komopdf modifies text at the PDF stream operator level rather than drawing HTML overlays:

• In-Place Replacement: Select existing text blocks or characters to replace their string content while maintaining grapheme cluster boundaries and baseline alignment.
• Multi-Line Insertion: Insert paragraphs with automatic text wrapping, custom line height multipliers, paragraph margins, and alignment (left, center, right). Empty lines do not generate phantom PDF objects.
• Typography & Styles: Adjust font size, fill color, character spacing, and true font weights. Italic slant and bounding box extents are calculated from raw font glyph metrics.
• Bundled Fonts (6 families, 18 faces): Noto Sans CJK SC (Regular/Bold), Noto Serif CJK SC (Regular/Bold), LXGW WenKai (Regular/Medium), Liberation Sans (4 styles), Liberation Serif (4 styles), and Liberation Mono (4 styles).
• Custom Font Import: Load external TTF or OpenType/CFF files, select individual faces from TrueType Collection (.ttc) files, or query authorized browser system fonts.

Manipulate individual pages or merge multi-document content seamlessly:

• Rotation: Rotate selected pages by 90°, 180°, or 270°. Existing page annotations and form fields adapt accordingly.
• Page Reordering: Drag and drop page thumbnails to reorder document sequences in a single atomic transaction.
• Page Insertion & Duplication: Insert blank pages at any position or clone existing pages along with their vector resources.
• Import from External PDF: Import specific page ranges from an external PDF file into the active document. Imported pages are incorporated as native page dictionaries without rasterization.
• Page Deletion: Remove unneeded pages with immediate undo availability. Documents must retain at least one page.

Object-level operations operate through stable object identifiers and affine transformations:

• Image Insertion: Embed PNG and JPEG images with preservation of full alpha transparency and resolution.
• Shared Instance Isolation: Replacing an image that appears multiple times in a document automatically isolates the modified instance so other pages remain untouched.
• Reversible Crop: Crop raster images non-destructively by adjusting clipping paths. Original image byte streams are preserved in the transaction history.
• Object Transformation: Move, scale, rotate, and align text and graphical objects on the canvas using direct mouse handles or numerical inputs.

Security operations are driven by QPDF 12.4.1 compiled to WebAssembly (browser) and native binaries (desktop):

• AES-256 Encryption: Apply standard 256-bit AES encryption with user and owner passwords. Specify permissions for printing, copying, and modification.
• Password Protected Opening: Open encrypted PDFs with user or owner credentials. If a password fails, retry without corrupting previously loaded workspace state.
• Lossless Linearization: Optimize PDF object streams, cross-reference tables, and unreferenced object garbage collection without lossy image re-compression.
• Zero Cloud Leakage: Passwords and encryption keys are processed strictly in memory within the local browser tab or native process.

The built-in assistant komo operates under strict verification protocols:

• Candidate Generation: komo never writes directly to your PDF file. AI suggestions are rendered as previewable diff candidates.
• Explicit Acceptance: You review the proposed changes before committing them into the transaction log. A discarded suggestion leaves zero artifacts.
• Scoped Payloads: Only the specific text snippet, prompt instruction, or bounding box necessary to fulfill your request is transmitted to the gateway.
• Rate & Budget Limits: The gateway enforces strict token and request limits to ensure service stability without tracking user identities.

komopdf maintains an immutable command journal enabling reliable state recovery:

• Undo / Redo: Ctrl+Z / Cmd+Z to undo; Ctrl+Y / Cmd+Shift+Z to redo.
• Grapheme Navigation: Arrow keys and Shift selections navigate by Unicode grapheme clusters, preventing corrupted surrogate pairs.
• Save Safeguards: Navigating away from a modified document prompts a confirmation modal to avoid accidental data loss.