[base, smooth] Implement direct LCD filtering.
Applying an LCD filter to spans rather than the entire image improves
the performance of ClearType-like rendering by about 40% at 32 ppem
and much more at larger sizes. Small rounding differences are expected.
* src/smooth/ftsmooth.c (ft_smooth_raster_lcd, ft_smooth_lcd_spans,
ft_smooth_raster_lcdv, ft_smooth_lcdv_spans, TOrigin): Implement it.
* include/freetype/internal/ftobjs.h (FT_LibraryRec): lcd_filter_func gone.
* src/base/ftlcdfil.c (ft_lcd_filter_fir): Removed.
(ft_lcd_padding): Use padding sufficient for any 5-tap filter.
(FT_Library_SetLcdFilterWeights, FT_Library_SetLcdFilter): Updated.
* docs/CHANGES: Updated.
4 files changed
