Fix antialiasing with transformed text in OpenGL2 paint engine

Since the paint engine now transforms the prerendered glyphs instead of
rendering transformed glyphs as paths, we need to turn on texture
filtering to avoid antialiasing artifacts. In order to do this, we also
need to pad the glyphs in the glyph cache, otherwise you will get
artifacts when sampling the area around the glyph's bounding rect (where
there might be other glyphs.) This done by adding a glyphPadding()
function to the cache which returns the number of pixels to pad between
each glyph.

Updated: This also fixes a general issue where some combinations of font
sizes and transformations will cause the engine to sample neighbouring
glyphs, so this has been backported to Qt 4.6.x.

Task-number: QTBUG-9706, QTBUG-11028
Reviewed-by: Tom

Conflicts:

	src/gui/painting/qtextureglyphcache.cpp
	src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
(cherry picked from commit 21f5bf3a3030a393ba17ce7726b70fe853b5b608)

0 files changed, 0 insertions, 0 deletions