Support placing cursor in ligature with mouse or touch

We need to find out the closest element in the ligature to
the point we clicked (or tapped), currently we do this by
dividing the width of that ligature glyph evenly by the number
of characters it covered. We only support Common and Greek script
at this point, ligatures in other scripts are still handled as a
whole.

Task-number: QTBUG-19260
Reviewed-by: Eskil
(cherry picked from commit 5338d78aa9d80ddd2bcb21e6b22cd2cf1522a7d3)

Change-Id: Ic747e9458d561aca0848dcd1e8b94e0a23fd8189
Reviewed-on: http://codereview.qt.nokia.com/196
Reviewed-by: Jiang Jiang <jiang.jiang@nokia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index ed24d5967b..055974a4ad 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -620,6 +620,7 @@ public:
     QFixed leadingSpaceWidth(const QScriptLine &line);
 
     QFixed offsetInLigature(const QScriptItem *si, int pos, int max, int glyph_pos);
+    int positionInLigature(const QScriptItem *si, int end, QFixed x, QFixed edge, int glyph_pos, bool cursorOnCharacter);
     int previousLogicalPosition(int oldPos) const;
     int nextLogicalPosition(int oldPos) const;
     int lineNumberForTextPosition(int pos);
@@ -642,6 +643,7 @@ private:
     void resolveAdditionalFormats() const;
     int endOfLine(int lineNum);
     int beginningOfLine(int lineNum);
+    int getClusterLength(unsigned short *logClusters, const HB_CharAttributes *attributes, int from, int to, int glyph_pos, int *start);
 };
 
 class QStackTextEngine : public QTextEngine {