Diagonal lines with QPainter::DrawLine() paints at wrong coördinates.

When drawing a diagonal line using QPainter::DrawLine() with a linewidth of 1, the start and end coördinates are of by one.
Examples:

painter.drawLine(2, 7, 6, 1);

Qt 4.8.5: a line will be drawn from x2, y7 to x6, y1

This is exactly as advertised in the Qt5 doc: http://qt-project.org/doc/qt-5/coordsys.html

Qt 5.2.1: a line will be drawn from x1, y7 to x5, y1

painter.drawLine(10, 10, 16, 4); (a line with an angle of exactly 45 degrees)

Qt 4.8.5: a line will be drawn from x10, y10 to x16, y4

Qt 5.2.1: a line will be drawn from x10, y9 to x16, y3

I provide a small project that demonstrates the problem.
I also provide some screenshots in PNG and XCF format (can be opened with The Gimp).
When compiled with Qt 4.8.5, the output of DrawLine() is as expected and as advertised in the Qt5 doc:
http://qt-project.org/doc/qt-5/coordsys.html