Rasterization sub-banding is utilized at large sizes while using
rather small fixed memory pool. Indeed it is possible to make an
educated guess how much memory is necessary at a given size for a
given glyph. It turns out that, for large majority of European glyphs,
you should store about 8 times more boundary pixels than their height.
Or, vice versa, if your memory pool can hold 800 pixels the band
height should be 100 and you should sub-band anything larger than
that. Should you still run out of memory, FreeType bisects the band
but you have wasted some time. This is what has been implemented in
FreeType since the beginning.
It was overlooked, however, that the top band could grow to twice the
default band size leading to unnecessary memory overflows there. This
commit fixes that. Now the bands are distributed more evenly and
cannot exceed the default size.
Now the magic number 8 is really suitable for rather simple European
scripts. For complex Chinese logograms the magic number should be 13
but that is subject for another day.
* src/smooth/ftgrays.c (gray_convert_glyph): Revise sub-banding
protocol.
* src/smooth/ftgrays.c (TArea): Restore original definition as `int'.
(gray_render_line) [FT_LONG64]: Updated.
(gray_convert_glyph): 32-bit band bisection stack should be 32 bands.
(gray_convert_glyph_inner): Trace successes and failures.
This patch restores original `TCoord' definition as `int' so that the
rendering pool is used more efficiently on LP64 platforms (unix).
* src/smooth/ftgrays.c (gray_TWorker, TCell, gray_TBand): Switch some
fields to `TCoord'.
(gray_find_cell, gray_render_scanline, gray_render_line, gray_hline,
gray_sweep, gray_convert_glyph): Updated.
* src/smooth/ftgrays.c (gray_convert_glyph): Do not use volatile
qualifier.
(gray_raster_render): Move span initializations from here.
(gray_sweep): ... to here and remove unused `target' argument.
* src/smooth/ftgrays.c (gray_init_cells): Remove function.
(gray_TWorker): Remove fields that become local variables.
(gray_raster_render): Move rendering buffer declaration from here.
(gray_convert_glyph): ... to here and update accordingly.
Removing the checks from `gray_hline' shaves 1% off rendering speed.
* src/smooth/ftgrays.c [STANDALONE_]: Duplicate `FT_MIN' and `FT_MAX'.
(gray_TWorker): No need to store `clip_box'.
(gray_hline): Remove unnecessary boundary checks.
(gray_convert_glyph): Move boundary checks from here.
(gray_raster_render): ... to here and consolidate.
* src/smooth/ftgrays.c [STANDALONE_]: Duplicate `FT_Outline_Get_CBox'.
(gray_compute_cbox): Remove this function.
(gray_convert_glyph): Update to use `FT_Outline_Get_CBox'.
The convergence of Bézier flatteners is fast with the deviation
from straight line being assymptotically cut 4-fold on each bisection.
This justifies smaller bisection stack size.
* src/smooth/ftgrays.c (gray_TWorker): Remove common `bez_stack'.
(gray_render_conic): Create and use conic `bez_stack'. Move back the
band analysis from...
(gray_conic_to): ... here.
(gray_render_cubic): Create and use cubic `bez_stack'. Move back the
band analysis from...
(gray_cubic_to): ... here.
(gray_move_to): Updated.
A single decrement counter of segments to draw, instead of an array,
contains all the information necessary to decide when to split and
when to draw a conic segment. The number of splits before each draw is
equal to the number of trailing zeros in the counter.
* src/smooth/ftgrays.c (gray_TWorker): Remove `lev_stack'.
(gray_render_conic): Updated to use decrement counter of segments.
* src/smooth/ftgrays.c (gray_render_conic, gray_render_cubic): Move
band clipping from here.
(gray_conic_to, gray_cubic_to): ... to here.
(gray_rander_line, gray_render_scanline): Initialize variables closer
to their use.
Such macro names are reserved for both C and C++.
* include/freetype/ftimage.h, src/raster/ftraster.c,
src/smooth/ftgrays.c, src/smooth/ftgrays.h:
s/_STANDALONE_/STANDALONE_/.
This implementation renders the entire line segment at once without
subdividing it into scanlines. The main speed improvement comes from
reducing the number of divisions to just two per line segment, which
is a bare minimum to calculate cell coverage in a smooth rasterizer.
Notably, the progression from cell to cell does not itself require any
divisions at all. The speed improvement is more noticeable at larger
sizes.
* src/smooth/ftgrays.c (gray_render_line): New implementation.
This change is a result of a discussion thread on freetype-devel
http://lists.nongnu.org/archive/html/freetype-devel/2015-06/msg00041.html
Re-introduce the `freetype2' subdirectory for all FreeType header
files after installation, and rename the `freetype2' subdirectory in
the git repository to `freetype'.
* include/freetype2: Renamed to...
* include/freetype: This.
* CMakeLists.txt (PUBLIC_HEADERS, PUBLIC_CONFIG_HEADERS,
PRIVATE_HEADERS): Updated.
Update creation of `ftconfig.h'.
Install generated `ftconfig.h'.
* Jamfile (HDRMACRO, RefDoc), autogen.sh: Updated.
* builds/amiga/include/config/ftconfig.h, builds/freetype.mk
(PUBLIC_DIR), builds/symbian/bld.inf, builds/toplevel.mk (work),
builds/unix/freetype2.in: Updated.
* builds/unix/freetype-config.in: Updated.
* builds/unix/configure.raw: Don't check for `rmdir'.
* builds/unix/unix-def.in (DELDIR): Use `rm -rf', which is portable
according to the autoconf info manual.
* builds/unix/install.mk (install, uninstall,
distclean_project_unix): Update and simplify.
* builds/wince/*, builds/windows/*: Updated.
* devel/ft2build.h, include/ft2build.h: Updated.
* include/freetype2/config/ftheader.h,
include/freetype2/internal/ftserv.h,
include/freetype2/internal/internal.h: Update all header file
macros.
* src/tools/chktrcmp.py (TRACE_DEF_FILES): Updated.
* docs/*: Updated.
We no longer `pollute' the namespace of possible header file names;
instead we move `ft2build.h' up by one level so that it gets
installed in the default include directory (e.g.,
/usr/local/include). After this commit, only `ft2build.h' stays in
the compiler's include path.
No visible changes for the user who follows the standard FreeType
header inclusion rules.
* include/*: Move to ...
* include/freetype2/*: This directory, except `ft2build.h'.
* CMakeLists.txt (PUBLIC_HEADERS, PUBLIC_CONFIG_HEADERS,
PRIVATE_HEADERS), Jamfile (HDRMACRO, RefDoc), autogen.sh: Updated.
* builds/amiga/include/config/ftconfig.h, builds/freetype.mk
(PUBLIC_DIR), builds/symbian/bld.inf, builds/toplevel.mk (work),
builds/unix/install.mk (install, uninstall),
builds/unix/freetype2.in: Updated.
* builds/unix/freetype-config.in: Updated.
Emit -I directory only if it is not `/usr/include'.
* builds/wince/*, builds/windows/*: Updated.
* devel/ft2build.h, include/ft2build.h: Updated.
* include/freetype2/config/ftheader.h,
include/freetype2/internal/ftserv.h,
include/freetype2/internal/internal.h: Update all header file
macros.
* src/tools/chktrcmp.py (TRACE_DEF_FILES): Updated.
* docs/*: Updated.
Looks like `ras.span_y' could always be used without initialization.
This was never detected by valgrind before because the library-wide
`raster_pool' was used for the worker object and `raster_pool' was
originally zero'ed. But subsequent reuses of it were using `span_y'
uninitialized. With the recent change to not use `render_pool' and
allocate worker and buffer on the stack, valgrind now detects this
uninitialized access.
* src/smooth/ftgrays.c (gray_raster_render): Initialize
`ras.span_y'.
