It was a simple bug in the XY Cut layout recognition code that made it too eager to see columns everywhere.
Also removed the dependence of the layout analysis algorithms on the display DPI (introduced by the recently added feature of using KScreen) to make their behavior more predictable and reproducible.
BUGS: 326207
BUGS: 331090
FIXED-IN: 4.13.0
REVIEW: 115759
Also simplified code a bit by removing unnecessary calls to toLower in TextPagePrivate::findTextInternalForward and TextPagePrivate::findTextInternalBackward I also fixed a small bug: the letter capital I with dot above (U+0130) did not match itself in case-insensitive mode on Qt 4.8.4 (U+0130 still does not match lowercase i (U+0069), which can be considered another bug, that I didn't fix (although this behavior conforms to the Unicode case folding rules)).
(I did not implement the Knuth-Morris-Pratt algorithm that I promised in a comment of Bug 323263 because on second thought I find that the win, if any, would probably be negligible except for some very special documents and special query strings.)
BUGS: 323262
BUGS: 323263
REVIEW: 112135
Albert Astals Cid
Kevin Funk
Martin T. H. Sandsmark
Lukáš Tinkl
Montel Laurent
Frederik Gladhorn
Fabio D'Urso
Jaan Vajakas