Strobe extracts text from a PDF and displays it one word at a time. Import through Files, use bookmarks to navigate chapters, and control playback by holding, tapping, or using a keyboard.
Import the PDF
Strobe imports files through the system file picker. In the library, tap Add, choose Import File…, and pick the PDF from Files, iCloud Drive, or any storage provider listed there. If the PDF is attached to an email or open in Safari, save it to Files first. On iPad, you can also drag a PDF onto the library.
For part of a document, such as one section of a long report, copy the text and choose New Text… instead. Strobe shows the word count and an estimated reading time at your default speed before you add it.
Import happens entirely on your device. The text, your reading progress, and your settings stay there; nothing is uploaded.
What the import keeps and removes
Strobe reads the text layer of the PDF, not the picture of the page. With Clean Up Text on, the default, it removes headers and footers that repeat across pages, standalone page numbers, lines such as “Page 3 of 20”, table-of-contents leader dots, ISBNs, copyright lines, and similar boilerplate. Words split by a hyphen at the end of a line are joined back together.
If the PDF has bookmarks, they become chapters. Each chapter begins at the top of the page its bookmark points to, and the document’s page lists every chapter with its reading time at your speed.
If cleanup ever removes text you need, turn off Clean Up Text in Settings and import the file again. The setting applies to new imports; documents already in your library don’t change.
Scanned pages, passwords, tables, and figures
Strobe requires a PDF text layer and does not run OCR. For an image-only PDF, add a text layer with an OCR tool before importing.
Password-protected PDFs can’t be imported either. Remove the password in the app you use to open the file, or ask the sender for an unprotected copy, and import that.
Clean Up Text removes lines made up mostly of numbers, which can include table data. For tables and figures, keep the original PDF open alongside Strobe; on iPad, you can use Split View.
Hold, tap, or step
By default, you hold anywhere on the screen to read and lift your finger to pause. While holding, drag up to speed up and down to slow down. That change lasts only for the current hold, so a dense paragraph can get a slower pass without changing the document’s speed. To change the speed itself, use the slider at the top of the reader while paused.
On a long session, holding can get tiring. Turn off Hold to Read in Settings, and a tap starts reading while a second tap pauses. In either mode, swipe sideways while paused to step through the text a word at a time.
Strobe runs in portrait on iPhone. On iPad, it works in any window size, including Split View next to the original PDF, which keeps figures and tables one glance away.
Search the passage and use a keyboard
Tap the text button at the top of the reader to open the full passage with your current word highlighted. Search for a word or a phrase, step between matches, and tap any word to continue reading from there. It is the quickest way to recover a definition or a claim from a few pages back.
With a keyboard connected to an iPad, Space starts and pauses reading, the left and right arrow keys step through words, and Escape leaves the reader.
For reports and papers, read in sections rather than cover to cover. The chapter list shows how long each section takes and which ones you have finished, and a short summary at the end of each section catches gaps before they compound.
Product sources
This guide is written by Jaafar Abdeen, Strobe’s developer. For current app compatibility and features, check the Strobe App Store listing. The public source code documents the implementation.