Bitmap metrics presetting [1/2].

This mainly just extracts the code for presetting the bitmap metrics
from the monochrome, grayscale, and LCD renderers into a separate
function.

* src/base/ftobjs.c (ft_glyphslot_preset_bitmap): New function that
calculates prespective bitmap metrics for the given rendering mode.
* include/freetype/internal/ftobjs.h (ft_glyphslot_preset_bitmap):
Declare it.

* src/base/ftlcdfil.c (ft_lcd_padding): New helper function that adds
padding to CBox taking into account pecularities of LCD rendering.
* include/freetype/ftlcdfil.h (ft_lcd_padding): Declare it.

* src/raster/ftrend1.c (ft_raster1_render): Reworked to use
`ft_glyphslot_preset_bitmap'.
* src/smooth/ftsmooth.c (ft_smooth_render_generic): Ditto.
(ft_smooth_render_lcd, ft_smooth_render_lcd): The pixel_mode setting
is moved to `ft_glyphslot_preset_bitmap'.
7 files changed