Free Reading Ruler

Worked example

The page opens with sample text, a band 40 px high ("Band height") and everything else dimmed by 55% ("Dim"). Move the mouse down the text and the band follows the pointer. Click once and the page says "Band locked. Click the text, double-tap it, or press Unlock to resume following." The band stays put while you look away; click again to release it. Now set "Band height" to 60, "Dim" to 70 and "Text size" to 22, choose "Both" under "Band style" to add a colour tint, pick another swatch under "Tint", and set "Spacing" to "Wide". Press "✎ Edit text", paste your own paragraph, then press "✓ Done". Press "Full screen" for a page that fills the screen; "Exit full screen" or the Esc key brings you back.

Which settings to use, and the limits

• Move the band with a mouse, the keys or a finger. With a mouse or pen the band follows the pointer, and a click locks or releases it. For the keyboard, tab to the text, or click it, which also locks the band: the down and up arrows move one line, Shift with an arrow moves two, PageDown and PageUp move about a screen, and Home and End jump to the ends. "Previous line" and "Next line" step one line. On a touch screen the text scrolls under a band fixed at the centre of the box. Double-tap, or press "Lock band", to pin the band to the text. A single tap never locks it.
• Set the band height, dim level and tint to suit you. "Band height" runs from 20 to 90 px and starts at 40. "Dim" runs from 0 to 90 percent and starts at 55. "Text size" runs from 14 to 28 px and starts at 18. "Band style" offers "Dim the rest", "Colour tint" and "Both"; with "Colour tint" the "Dim" slider is greyed out. "Tint" has five swatches and a "Custom colour" picker. The band always has a 2 px line in the tint colour at its top and bottom.
• Change the background, font and spacing for comfort. "Background" offers "Match site" (the default), "White", "Cream" and "Dark". "Font" offers "Default" or "Easy-read", which asks for Atkinson Hyperlegible and then Verdana, Tahoma or Trebuchet MS from the fonts already on your device. "Spacing" offers "Normal", "Wide" and "Extra wide". Wide adds 0.05em between letters and 0.16em between words, with line height 1.9. Extra wide adds 0.1em and 0.3em, with line height 2.2. Normal line height is 1.625.
• Bring your own text, and know what is remembered. "Open a file…" reads TXT, MD, DOCX, PDF, EPUB and HTML files up to 200 MB, then says "Loaded name (1234 characters)." Text from PDF, DOCX, EPUB and HTML is re-flowed: line breaks inside a paragraph become spaces and hyphenated words are rejoined. TXT keeps its line breaks. Your settings and pasted text are kept in this browser; the untouched sample, and text over 1,000,000 characters, are not. "Use sample text" resets the text. Adding #text= and your words to the page address pre-fills the text, up to 50,000 characters.
• Use full screen for long reading. "Full screen" uses the browser's own full screen where it exists and a fixed overlay where it does not. Esc or "Exit full screen" leaves it. The text is drawn 4 px larger than your "Text size", with wider side margins on larger screens. The bar at the top keeps "Band height", "Dim", "Previous line", "Next line" and "Lock band", but the colour, font and spacing controls are not shown there, so set them first.
• Take the ruler to any web page. Drag the "Reading ruler" button to your bookmarks bar, or press "Copy bookmarklet code". Click the bookmark on any page and the same band appears over it. A mouse moves the band, and a finger drags it 70 px above the fingertip. Esc or the × button removes it, and clicking the bookmark again also toggles it off. The bookmark carries your band height, dim level and tint at the time you dragged it, so drag it again after changing them. It always dims, whatever "Band style" is.

Common problems and how to fix them

It says "That file has no readable text (a scanned PDF, for example)."

The tool reads the text layer of each PDF page. A scanned PDF holds only pictures of pages, so it found no letters or digits at all. An EPUB made only of pictures behaves the same way. Run the scan through the OCR tool first and copy the result, then paste it after pressing "✎ Edit text". A PDF exported from a word processor normally has a text layer and opens fine.

It says "That file type is not supported. Try TXT, DOCX, PDF, EPUB or HTML."

The file passed the first check but its name and type are not one of the readable kinds, which happens with a .zip, for example. An old Word .doc file is turned back earlier, with a message such as "report.doc is a DOC file, which this tool can't open." In the program that made the file, save or export it as DOCX, PDF or TXT, then open that.

It says "That file could not be read. It may be damaged or password-protected."

The reader started but could not parse the file. A password-protected PDF ends here, because the tool cannot ask for a password. So does a damaged DOCX or EPUB, or any unexpected error while reading. Remove the password or download the file again. As a last resort, copy the text from another program and paste it after pressing "✎ Edit text".

It says "The file reader could not load. Check your connection and try again."

PDF, DOCX and EPUB files each need a reader that is fetched the first time you use it. If that download fails, nothing is read. Check your connection and open the file again. TXT files and pasted text do not need these readers.

The band will not follow the mouse, and the page says "Band locked. Click the text, double-tap it, or press Unlock to resume following."

A click on the text, or a double-tap or "Lock band" on a touch screen, pinned the band. While it is locked the pointer no longer moves it. Click the text again or press "Unlock band". A locked band can still be moved with the arrow keys, PageUp and PageDown, and "Previous line" and "Next line". On a touch screen, unlocking puts the band back at the centre of the box.

How it compares

This is a focus aid, not a reader. It dims the lines around one band of text so your eye stays on the current line, and it works on text you paste, on a file you open, or on any web page through the bookmarklet. It does not read aloud, correct spelling or change a document. As the page itself says, it cannot draw over a PDF viewer or another app, so for those you open the file here instead. A paper ruler or a coloured overlay works on printed books, which this cannot. In exchange you get exact band sizes, tints and dim levels, keyboard stepping, and settings that are remembered on this device.