Up and running in five minutes.

1 · Open a file

Click Open file on the start screen, drag a file onto the window, or double-click a PDF in Finder or File Explorer once RyDF is your default PDF viewer — it offers to take that job the first time you launch, and Preferences ▸ Default PDF viewer settles it any time after. On Windows, saying yes opens the Settings Default apps page to finish there; no app is allowed to claim a file type for itself.

Pictures work too — JPEG, PNG, TIFF, WebP, GIF, BMP and SVG, which opens as real vector rather than a traced image. HEIC needs nothing extra on macOS; on Windows it needs Microsoft's free HEIF Image Extensions from the Store. Big files open straight to page 1 while the rest streams in — no waiting on a spinner. Open more than one and they stack up as tabs you can flip between instantly, however you open them.

Move around with scroll and pinch-to-zoom (or ⌘+ / ⌘−), jump to a page with the page box, and use the Pages, Outline, Layers, Markups and Search tabs in the sidebar. On Windows, press Ctrl wherever this page says ⌘.

2 · Mark it up

Pick a tool from the toolbar — the tools are grouped by category:

• Draw — rectangles, ellipses, revision clouds, lines, arrows, polylines, freehand pen and a highlighter.
• Text — text boxes, callouts and sticky notes.
• Select text — drag across the page's own text and a bar offers Highlight, Underline, Strikeout and Copy. Select marked words again and Clear takes the mark off.
• Stamp — reusable stamps with repositionable text.
• Signature — sign by typing your name in a cursive style, or import an image (RyDF can knock out a white background).

Set color, fill, stroke width and opacity in the properties bar. Select any markup to move, resize or restyle it — and your last-used style becomes the default for the next one of that kind.

3 · Measure to scale

1. Choose the Measure tools, then Set scale from measurement. If the sheet states its own scale RyDF has already read it — the status bar says so and you can measure straight away. Set scale from ratio takes an architectural ratio like 1/4"=1' with no line to draw.
2. Draw a line across something whose real length you know — a dimension string, a known wall. Turn on snap to geometry to lock onto the drawing's own line endpoints.
3. Type the real length and units. That sets the page's scale.
4. Now measure freely — distances read out in your units. Need a one-off? The quick-measure tape stays on screen marked temporary dimension until you switch tools, and never touches the document. Scale is remembered per page, so mixed-scale sets just work.

4 · OCR a scan (optional)

If a page is a scan or image with no selectable text, click OCR, choose the current page / selected pages / all pages, and RyDF reads the text on the machine — Apple's Vision framework on macOS, Windows' own recognizer on Windows, nothing uploaded either way — then bakes in an invisible, searchable layer. On Windows this needs a recognition language installed under Settings → Time & language → Language & region. Leave it on Most accurate for a drawing — it reads the sheet in finer pieces, each one turned every way, so vertical title-block and dimension labels are caught, for about four times the time; choose Fast, one upright pass, for ordinary prose. Large sheets are read in overlapping tiles, which is what gets the fine print. The scan becomes selectable and searchable — in RyDF and anywhere else the PDF goes.

5 · Organize & print

In the Pages sidebar (or the full grid view) you can rotate, delete, extract, insert and reorder pages by drag-and-drop. When you're ready, hit Print (⌘P): set copies and scale to fit, print the whole document or just the pages you selected, and check the preview before it goes. Pages leave as real vector at the driver's resolution, not a picture of the screen. The user guide covers the rest of the print options, and which of them Windows still leaves to the printer driver's own defaults.

That's the whole loop. For deeper questions, see the FAQ; to install, head to Downloads — a signed .dmg on macOS, and on Windows an .exe installer that isn't code-signed yet, so the first run takes a More info then Run anyway to get past SmartScreen.