@pdfrx/viewer-core

Platform-independent core logic of a PDF viewer, in pure TypeScript. No DOM access — every type is a plain JSON-serializable object. This is the logic layer underneath @pdfrx/viewer; use it directly to build a custom viewer shell (different rendering stack, custom gestures).

Derived from the pdfrx project.

npm package · API reference

Installation

npm install @pdfrx/viewer-core

What's inside

| Module | Contents | |---|---| | geometry | Rect/point math, page rotation, PDF page space (y-up) ↔ document space (y-down) conversions | | transform | ViewTransform {zoom, xZoomed, yZoomed}, visible-rect/fit calculations, 14 page anchors, boundary clamping, underflow alignment | | layout | Vertical/horizontal page layout and hit testing | | text / text-formatter | Structured page text: reading-order analysis, line splitting, word/space/newline fragments, text direction (LTR/RTL/vertical), search | | selection | Nearest-character hit testing, A/B selection anchors (same-page and cross-page), word selection, per-page range expansion for highlighting |

These primitives are DOM-free and JSON-serializable. They support vertical, horizontal, and custom viewer shells without coupling layout, coordinates, text analysis, or selection behavior to canvas rendering or a UI framework.

Example

import {
  formatText,
  findTextAndIndexForPoint,
  getSelectedRanges,
  composeSelectedText,
  layoutPagesVertical,
} from '@pdfrx/viewer-core';

// Build structured text from an engine's raw page text
const pageText = formatText({ fullText, charRects }, /* pageNumber */ 1);

// Lay out pages and hit-test a pointer position against the text
const layout = layoutPagesVertical(pages, { margin: 8 });
const hit = findTextAndIndexForPoint(docPoint, selectablePages);

// Expand a selection into per-page ranges and compose the clipboard text
const ranges = getSelectedRanges(selA, selB, getLoadedText);
const clipboard = composeSelectedText(ranges);

Coordinate conventions: PDF page space is points (1/72"), origin bottom-left, y-up; document space is y-down. See the architecture notes for details.

Next steps

See the complete API reference for exported geometry, layout, text, and selection symbols. The architecture notes define coordinate conventions and package boundaries.

• Related packages: @pdfrx/engine · @pdfrx/viewer · @pdfrx/react

License

MIT