A New Approach to Low Vision Accommodation

Most scientific articles in PDF are unreadable for people with partial sight. PDF files often drop true space characters. They treat text as pictures — placing words by coordinates, not by letters and spaces. Gaps are blank areas, not characters.

For a sighted reader, this looks fine. But reflow, the process that lets text wrap when enlarged, needs real spaces to find word breaks. When they are gone, words fuse. “Paper airplane” becomes “paperairplane.” The result breaks reading comprehension and fails WCAG 2.1 Success Criterion 1.4.10 (Reflow).

The purpose of this work is to restore space characters where they belong. By rebuilding the missing spaces between words and formulas, we turn a fixed PDF image into true text. Once rebuilt, PDF can reflow at large print sizes. Readers with low vision can finally use magnification and wrapping without distortion.

We call the algorithm Water. It reads the page as a sighted person would — by shape, not by code. It analyzes where white space surrounds black ink. The white forms an ocean; text and formulas are islands. The program measures these rectangles and maps them into a logical layout.

From the geometry of gaps, we can tell where words, symbols, and lines should separate. Those positions become true space characters in the output PDF.

This approach relies on a simple fact: in print, physical space carries meaning. The gap between letters inside a word is small. Between words it is wider. Between formula terms it is in between. These patterns let sighted readers distinguish words and formulas.

Water uses this geometric logic to reconstruct meaning. It restores the invisible structure that makes language readable.

Once rebuilt, the text can return to PDF — not as a picture, but as a complete document. PDF handles enlargement better than any other format. It preserves sharp curves, straight lines, and exact letter forms at any size. When the spaces are fixed, those same Bezier curves that once locked text in place now make it fluid.

With reflow restored, readers can magnify text freely. Words stay whole. Lines wrap. The document remains readable and attractive, no matter how large the print.