Scrolling capture

Capture a page, chat or document that is taller than your screen as one image.

Steps

Press ⇧⌘7, or choose Scrolling in the menu.
Drag over the part of the screen that scrolls. Pick just the content area, not toolbars.
A small bar appears: "Scroll down slowly…".
Scroll down with your trackpad or mouse. A thin accent frame marks the area, and a small size label at its bottom-right (for example "720×3400") grows as the image does. Neither is part of the image.
Click Done (or press Return) to finish. Click Cancel to throw it away.

The shutter sounds and the thumbnail appears at once, with every action available. A scrolling capture is saved uncovered and checked for sensitive items in the background: if it finds some, the thumbnail and Library tile get the key badge, a toast says how many with a Redact button, and Redact covers them on request. (With After capture set to Copy or Save it is covered first.) A badge such as "↕ 3×" says how many screens tall the image is; it also shows on the Library tile and in Recent and Search. The file is a PNG named "Scrolling Screenshot …"; the badge survives a rename.

The controls

Done: stitches the frames and saves the image.
Cancel: discards everything.
Auto-Scroll: Frayo scrolls the content for you (see below). Not in the App Store version.
Pause / Resume: only while Auto-Scroll runs (below).
Size label: at the bottom-right of the frame, the size in pixels of the image so far.

Auto-Scroll

Turn on Auto-Scroll in the bar. The frame pulses for a second ("Starting…"), then Frayo scrolls the area by itself, about 40% of its height at a time, waiting for the content to settle before each step. The bar says "Auto-scrolling · move the mouse to take over". When the page stops moving it says "Reached the end" and saves; it also stops at 30,000 pixels. Done and Cancel work as usual. The first time, a short tip explains Pause.

Pause / Resume. Pause stops the scrolling but not the capture: look around, click, or scroll by hand. Resume carries on from where the page is.
Take over any time. Touch the mouse or trackpad (scroll, click or move it) and Auto-Scroll stops; the capture keeps running, so scroll on by hand and press Done.
Remembered. The choice is kept: with it on, every new scrolling capture starts scrolling at once.
Accessibility. Scrolling for you needs Frayo in System Settings › Redaction & Security › Accessibility. The first time, Frayo opens that pane; until it is on, scroll by hand as before.
Your pointer stays put. The scroll is sent to the area without moving the pointer. Some apps only scroll under the pointer: if nothing moves, put the pointer over the area.

How it works

Frayo grabs the selected area many times a second. It compares each new frame with the last one, finds how far the content moved, and adds only the new rows at the bottom. Bars that stay put while the rest scrolls (a sticky header or footer) are kept once, at the top and the bottom.

Tips for a clean result

Scroll at a steady pace. If you scroll so far between two frames that they share nothing, the bar says "Scrolled too fast — scroll back up a little". Scroll back until the bar goes back to "Scroll down slowly…", then carry on. If you press Done without recovering, the image ends where it stopped growing and Frayo tells you so.
Scrolling back up is fine. Rows already captured are not added twice.
Long blank areas (a full screen of plain white) have nothing to match on and count as too fast. Scroll through them more slowly, or capture the page in two parts.
Stop at the end. Extra frames with no movement are ignored.

Limits

The image stops growing at 30,000 pixels tall. Frayo then finishes by itself.
It stitches by comparing pixels. Pages with animation or video inside the area may not match well.
If capture is blocked (permission removed or display gone), Frayo stops and explains. See Troubleshooting.

Test it

Scrolling capture is checked by unit tests and by an automated walkthrough (DEMO_ONLY=scrolling) that scrolls a test window, but only you can check it against real apps, real trackpads and real displays. Allow 20 minutes. For each case below: press ⇧⌘7, select the content area, scroll, press Done, then open the image from the thumbnail and read it top to bottom at 100%.

What a good result looks like: the page reads continuously, with no line repeated, no line missing and no seam; a sticky header or footer appears once; the image is as tall as the size label at the frame's bottom-right said.

App	What to do	Look for
Safari, a long article (for example a Wikipedia page or a blog with a sticky nav bar)	Select the whole page area including the sticky nav. Scroll slowly, then again at normal speed.	The nav bar appears once at the top. Pictures are not cut or doubled.
A code editor with a long file	Select the text area. Scroll with the trackpad.	No repeated line when many lines look alike (braces, blank lines, a long import list).
Slack (a busy channel)	Select the message list. Scroll up first to the start, then capture while scrolling down.	The composer bar at the bottom appears once. New messages arriving while you scroll can break matching: try a quiet channel too.
Finder, list view of a folder with 100+ files	Select the list. Scroll slowly, then fast.	Rows of similar names are not skipped or doubled.
Any page with a video or animated ad inside the area	Scroll normally.	It may stitch badly, which is a known limit. Note how bad.

Then try these on any of the above:

Slow scroll: about one screen every 5 seconds. The image must be perfect.
Fast flick: flick the trackpad hard once. The bar must say "Scrolled too fast — scroll back up a little". Scroll back up until the label shows a height again. Finish. Nothing may be missing.
Fast flick, then Done at once: the image ends at the last good place and a message says where it stopped.
Cancel: press Cancel part-way. Nothing is saved.
Very long page: keep scrolling. At 30,000 pixels the capture ends by itself and saves.
Retina and external display: repeat one case on the built-in screen and on an external display (ideally one that is not Retina). Move the selection so it sits wholly on one display. The image must be sharp and its width must be the selection width times the display scale.
Auto-Scroll: turn it on in the bar (grant Accessibility when asked). The page scrolls to the end by itself, the capture saves, and the image reads continuously. Repeat on a page with smooth scrolling and one with a sticky header.
Stop by touching the trackpad: during Auto-Scroll, touch the trackpad or move the mouse. Scrolling stops, the bar stays, a message says you took over; scroll on by hand and press Done.
Frame and thumbnail: the accent frame sits just outside your selection and never shows in the image; the size label is at its bottom-right and never shows either. After Done the shutter and thumbnail come at once, and the "↕ N×" badge matches the page (a page about three screens tall says 3×). Try a page with a visible key or token: Redact must be offered on the thumbnail and the Library tile.
Pause: during Auto-Scroll click Pause: the page stops, the capture keeps going. Moving the mouse to the bar must not count as taking over. Click Resume: it scrolls on.
Remembered, and no Accessibility: quit and capture again: Auto-Scroll starts on its own. Remove Frayo from Accessibility: the bar explains and manual capture still works.
Frame rate: during a slow scroll the size label should grow smoothly, several times a second. If it stutters or lags a second behind, report the Mac model and display.

Report anything that fails with the app, the display and what you did. A screenshot of the result and of the page is enough.