@nextgensoftwares/folio-plugin-protect

Protected reading in the browser: canvas pages with layers baked in, copy and print deterrents, tamper detection, and a pager for server-rendered page images. Guides: Reader & protection, Protected reading.

Components

Export	Description
`canvasPages(options)`	`ComponentType<PageViewProps>` for `<FolioView pageComponent>`: pages painted to `<canvas>`, guarded
`type CanvasPagesOptions`	`painters`, `math`, `images`, `resolveSrc`, `forensic`, `onTamper`, `beforeRender`, `maxScale`
`FolioProtect`, `type FolioProtectProps`	wrapper: copy/print/select/context-menu/drag rules, blur on focus loss or devtools, audit hooks
`type BlockedAction`	`'copy' \| 'print' \| 'save' \| 'contextmenu' \| 'drag' \| 'select'`
`FolioImagePager`, `type FolioImagePagerProps`, `type FolioImagePagerHandle`	server page images with scroll/page/spread modes, lazy loading, prefetch, keyboard and swipe; `pageAccess` locks pages without requesting their images; the handle is a `ReaderTarget`
`ImagePage`, `type ImagePageProps`	one lazily loaded page image (canvas or `<img>`)

Browser rendering

Export	Description
`rasterizePageInBrowser(options)`	a `PageRasterizer` for `exportFlattenedPdf` (PNG or JPEG via OffscreenCanvas)
`browserImageLoader(resolveSrc?)`	CORS `<img>` loader returning `LoadedImage`
`canvasMathFromHtml(render)`	canvas math from KaTeX HTML (vector glyphs, rules, paths)
`browserPath2d(d)`	`Path2D` factory for render-canvas
`createPageCanvas(width, height)`	OffscreenCanvas, else a `<canvas>`

Tamper detection

Export	Description
`diagnose(snapshot, expectation)`	pure check → `TamperKind[]`
`type TamperKind`	`'removed' \| 'injected' \| 'style' \| 'resized' \| 'hidden' \| 'pixels' \| 'stylesheet'`
`type TamperEvent`, `type TamperHandler`	`{ kind, page?, detail?, at }` and its callback
`type PageSnapshot`, `type PageExpectation`	what the guard reads and expects
`pixelChecksum(data, width, height)`	sampled checksum of RGBA pixels
`tamperReporter(handler, windowMs?, now?)`	rate-limited reporting (one per kind and page per window); a throwing handler is contained
`guardPage(options)`, `type GuardHandle`	MutationObserver + periodic check that repairs and reports
`snapshot(...)`, `canvasChecksum(canvas)`	DOM readers used by the guard

Copy, print, devtools

Export	Description
`limitCopy(text, policy, used?)`, `type CopyPolicy`, `type CopyDecision`	applies `'allow' \| 'block' \| { maxChars, budget }`
`blockedShortcut(event, opts)`	Ctrl/Cmd+P, S, U → `'print' \| 'save' \| null`
`devtoolsLikelyOpen(window, threshold?)`	docked-devtools heuristic (deterrent only)
`obscureReason(state, opts)`, `type ObscureReason`	why to blur: `'blur' \| 'hidden' \| 'devtools' \| null`
`protectCss`, `ensureProtectCss(doc, nonce?)`, `PROTECT_STYLE_ID`	the protection stylesheet