* src/raster/ftrend1.c (ft_raster1_render): Clean up the exit.
* src/smooth/ftsmooth.c (ft_smooth_render_generic): Reduce
translations and clean up the exit.
(ft_smooth_render_lcd, ft_smooth_render_lcd): Remove unused `error'..
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'.
Thing are simpler with a NULL-function pointer.
* include/freetype/internal/ftobjs.h (FT_Face_InternalRec): New
pointer to the filter function.
(FT_LibraryRec): Remove unused `lcd_filter'.
(FT_Bitmap_LcdFilterFunc, ft_lcd_filter_fir): Move from here...
* include/freetype/ftlcdfil.h (FT_Bitmap_LcdFilterFunc,
ft_lcd_filter_fir): ... to here.
* src/base/ftobjs.c (ft_open_face_internal): NULL-initialize the
per-face filter.
(FT_Face_Properties): Set it.
* src/smooth/ftsmooth.c (ft_smooth_render_generic): Simplify.
* src/base/ftlcdfil.c (ft_lcd_filter_fir, FT_Libary_SetLcdFilter):
Minor.
This is a new technology for LCD-optimized rendering. It capitalizes
on the fact that each color channel grid is shifted by a third of a
pixel. Therefore it is logical to render 3 separate monochrome
bitmaps shifting the outline by 1/3 pixel, and then combine them.
Importantly, the resulting output does not require additional LCD
filtering.
* src/smooth/ftsmooth.c (ft_smooth_render_generic)
[!FT_CONFIG_OPTION_SUBPIXEL_RENDERING]: Implement new LCD-optimized
rendering.
* include/freetype/ftlcdfil.h, include/freetype/freetype.h,
include/freetype/config/ftoption.h, devel/ftoption.h: Updated
documentation.
* src/smooth/ftgrays.c [STANDALONE] (OVERFLOW_ADD_LONG,
OVERFLOW_SUB_LONG, OVERFLOW_MUL_LONG, NEG_LONG): New macros.
[!STANDALONE]: Include FT_INTERNAL_CALC_H.
(gray_render_cubic): Use those macros where appropriate.
Extra bitmap padding for LCD filtering depends on the filter. The
default 5-tap filter needs 2 extra subpixels. The light 3-tap filter
needs only 1 extra subpixel. This space could be already available
due to rounding. In order to optimize the padding, we now expand
CBox for the given filter weights before rounding.
This change breakes current Skia (and Firefox).
* include/freetype/internal/ftobjs.h (FT_LibraryRec)
[FT_CONFIG_OPTION_SUBPIXEL_RENDERING]: Remove `lcd_extra' field.
* src/base/ftlcdfil.c (FT_Library_SetLcdFilterWeights,
FT_Library_SetLcdFilter): Remove `lcd_extra' initializations.
* src/smooth/ftsmooth.c (ft_smooth_render_generic): Implement dymanic
LCD padding.
This mode uses fractional advance widths and doesn't scale glyphs
horizontally, only applying vertical scaling and hinting.
At the same time, the behaviour of the `light' auto-hinter gets
restored for backwards compatibility: Both vertical and horizontal
scaling is again based on rounded metrics values (this was changed
in a commit from 2017-03-30 as a side effect). To be more precise,
the behaviour is restored for TrueType fonts only; for other font
formats like Type 1, this is a new feature of the `light' hinting
mode.
* include/freetype/freetype.h (FT_LOAD_TARGET_SLIGHT): New macro.
(FT_RENDER_MODE_SLIGHT): New render mode.
* include/freetype/internal/ftobjs.h (FT_Size_InternalRec): Add
`autohint_mode' and `autohint_metrics' fields.
* src/autofit/afcjk.c (af_cjk_hints_init), src/autofit/aflatin.c
(af_latin_hints_init), src/autofit/aflatin2 (af_latin2_hints_init):
Updated.
* src/autofit/afloader.c (af_loader_embolden_glyph_in_slot): Use
`autohint_metrics'.
(af_loader_load_glyph): s/internal/slot_internal/.
Initialize `autohint_metrics' and `autohint_mode' depending on
current auto-hint mode.
Use `autohint_metrics'.
Updated.
* src/base/ftadvanc.c (LOAD_ADVANCE_FAST_CHECK): Updated.
* src/base/ftobjs.c (FT_Load_Glyph): Updated.
(FT_New_Size): Allocate `internal' object.
* src/pshinter/pshalgo.c (ps_hints_apply): Updated.
* src/smooth/ftsmooth.c (ft_smooth_render): Updated.
We don't need some divisions if a line segments stays within a single
row or a single column of pixels.
* src/smooth/ftgrays.c (gray_render_line) [FT_LONG64]: Make divisions
conditional.
The algorithm calls `gray_set_cell' at the start of each new contour
or when the contours cross the cell boundaries. Double-checking for
that is wasteful.
* src/smooth/ftgrays.c (gray_set_cell): Remove check for a new cell.
(gray_convert_glyph): Remove initialization introduced by 44b172e88.
* src/smooth/ftgrays.c (gray_move_to): Call `gray_set_cell' directly
instead of...
(gray_start_cell): ... this function, which is removed.
(gray_convert_glyph): Make initial y-coordinate invalid.
It turns out that there is significant cost associated with `FT_Span'
creation and calls to `gray_render_span' because it happerns so
frequently. This removes these steps from our internal use but leaves
it alone for `FT_RASTER_FLAG_DIRECT" to preserve API. The speed gain
is about 5%.
* src/smooth/ftgrays.c (gray_render_span): Removed. The code is
migrated to...
(gray_hline): ... here.
Zero coverage is unlikely (1 out of 256) to warrant checking. This
gives 0.5% speed improvement in dendering simple glyphs.
* src/smooth/ftgrays.c (gray_hline, gray_render_span): Remove checks.
This gives 2% speed improvement in rendering simple glyphs.
* src/smooth/ftgrays.c (TPixmap): Reduced pixmap descriptor with a
pointer to its bottom-left and pitch to be used in...
(gray_TWorker): ... here.
(gray_render_span): Move pixmap flow check from here...
(gray_raster_render): .. to here.
This removes unnecessary complexity of span merging and buffering.
Instead, the spans are rendered as they come, speeding up the
rendering by about 5% percents as a result.
* src/smooth/ftgrays.c [FT_MAX_GRAY_SPANS]: Macro removed.
(gray_TWorker): Remove span buffer and related fields.
(gray_sweep, gray_hline): Updated.
* include/freetype/ftimage.h: Remove documentation note about
`FT_MAX_GRAY_SPANS', which was never in `ftoption.h' and is now gone.
