This patch undoes the fix for bug 12898. The texture coordinate
fix was coincidental, the real issue was an improperly calculated
bounding box, which was fixed in 5fff9333. This patch also fixes
issues with rotated text and other cases where bbox_text[0] < 0.0.

This patch has been tested against Paraview and the issue with
clipped text has indeed been fixed by 5fff9333.

Change-Id: If0496e90a4ddce6329cbde300792e23096d25455