This catches a rendering problem with glyph `x' from Tahoma at
10ppem. It seems that the increase of the precision in the change
from 2009-06-11 makes a larger jitter value unnecessary.
* src/raster/ftraster.c (Set_High_Precision): Implement it.
If a drop-out rule would switch on a pixel outside of the glyph's
bounding box, use the right (or top) pixel instead. This is an
undocumented feature, but some fonts like `Helvetica Neue LT Com 65
Medium' heavily rely on it.
Thanks to Greg Hitchcock who explained this behaviour.
* src/raster/ftraster.c (Vertical_Sweep_Drop,
Horizontal_Sweep_Drop): Implement it.
Problem reported by Tom Bishop <wenlin@wenlin.com>; see
thread starting with
http://lists.gnu.org/archive/html/freetype/2010-10/msg00049.html
* src/raster/ftraster.c (Line_Up): Replace FMulDiv with SMulDiv
since the involved multiplication exceeds 32 bits.
On LLP64 platforms (e.g. Win64), long (32-bit) cannot cover
the memory address (64-bit). Also the casts from the pointer
type to long int should be removed to preserve the address
correctly.
* src/raster/ftraster.c (New_Profile): Replace "%lx" by "%p".
(End_Profile) Ditto.
* src/truetype/ttinterp.c (Init_Context): Ditto.
This was broken since version 2.3.0.
* src/raster/ftraster.c (count_table): Use pre-2.3.0 values (which
were then computed dynamically).
(Vertical_Gray_Sweep_Step): Updated.
(ft_black_render): Initialize `worker->gray_lines' (problem found by
valgrind).
(FT_RASTER_OPTION_ANTI_ALIASING, DEBUG_RASTER): Dont' #undef, just
comment out.
Normally, the SCANMODE instruction (if present) to set the drop-out
mode in a TrueType font is located in the `prep' table only and thus
valid for all glyphs. However, there are fonts like `pala.ttf'
which additionally contain this instruction in the hinting code of
some glyphs (but not all). As a result it can happen that a
composite glyph needs multiple drop-out modes for its subglyphs
since the rendering state gets reset for each subglyph.
FreeType collects the hinted outlines from all subglyphs, then it
sends the data to the rasterizer. It also sends the drop-out mode
-- after hinting has been applied -- and here is the error: It sends
the drop-out mode of the last subglyph only; drop-out modes of all
other subglyphs are lost.
This patch fixes the problem; it adds a second, alternative
mechanism to pass the drop-out mode: For each contour, the
rasterizer now checks the first `tags' array element. If bit 2 is
set, bits 5-7 contain the contour's drop-out mode, overriding the
global drop-out mode.
* include/freetype/ftimage.h (FT_CURVE_TAG_HAS_SCANMODE): New macro.
* src/truetype/ttgload.c (TT_Hint_Glyph): Store drop-out mode in
`tags[0]'.
* src/raster/ftraster.c (Flow_Up, Overshoot_Top, Overshoot_Bottom):
Use bits 3-5 instead of 0-2.
(New_Profile): Set the drop-out mode in the profile's `flags' field.
(Decompose_Curve): Check `tags[0]' and set `dropOutControl' if
necessary.
(Vertical_Sweep_Drop, Horizontal_Sweep_Drop,
Horizontal_Gray_Sweep_Drop, Draw_Sweep): Use the profile's drop-out
mode.
Two new constraints are introduced to better identify a `stub' -- a
concept which is only vaguely described in the OpenType
specification. The old code was too rigorous and suppressed more
pixel than it should.
. The intersection of the two profiles with the scanline is less
than a half pixel. Code related to this was already present in
the sources but has been commented out.
. The endpoint of the original contour forming a profile has a
distance (`overshoot') less than half a pixel to the scanline.
Note that the two additional conditions fix almost all differences
to the Windows rasterizer, but some problematic cases remain.
* src/raster/ftraster.c (Overshoot_Top, Overshoot_Bottom): New
macros for the `flags' field in the `TProfile' structure.
(IS_BOTTOM_OVERSHOOT, IS_TOP_OVERSHOOT): New macros.
(New_Profile, End_Profile): Pass overshoot flag as an argument and
set it accordingly.
Update callers.
(Vertical_Sweep_Drop, Horizontal_Sweep_Drop): Implement the two new
constraints.
* src/raster/ftraster.c (Set_High_Precision): Add two more bits to
the precision. This corrects rendering of some small glyphs, for
example, glyph `xi' in verdana.ttf at 13 ppem. Testing with ftbench
on my GNU/Linux box I don't see a performance degradation.
Suggested by Alexei Podtelezhnikov <apodtele@gmail.com>.
* src/raster/ftraster.c (Vertical_Sweep_Drop, Horizontal_Sweep_Drop,
Horizontal_Gray_Sweep_Drop): Do it.
* src/raster/ftraster.c (TFlow): Replace enumeration with...
(Flow_Up): This macro.
(TProfile): Replace `flow' member with `flags' bit field.
Update all affected code.
Problem reported by Krzysztof Kotlenga <pocek@users.sf.net>.
* src/raster/raster.c (Vertical_Sweep_Drop, Horizontal_Sweep_Drop,
Horizontal_Gray_Sweep_Drop): For smart drop-out mode, if
intersections are equally distant relative to next pixel center,
select the left pixel, not the right one.
* src/raster/ftrend1.h declare ft_raster1_renderer_class
and ft_raster5_renderer_class
using macros from ftrender.h,
when FT_CONFIG_OPTION_PIC is defined create and destroy
functions will be declared.
* src/smooth/ftrend1.c when FT_CONFIG_OPTION_PIC is defined
ft_raster1_renderer_class and ft_raster5_renderer_class structs
will have functions to init or create and destroy them
instead of being allocated in the global scope.
Macros will be used from rastpic.h in order to access
ft_standard_raster from the pic_container (allocated in ftraster.c).
In ft_raster1_render when PIC is enabled, the last letter of
module_name is used to verfy the renderer class rather than the
class pointer.
* src/raster/ftraster.c when FT_CONFIG_OPTION_PIC is defined
ft_standard_raster struct will have function to init it
instead of being allocated in the global scope.
New Files:
* src/raster/rastpic.h declare struct to hold PIC globals for raster
renderer and macros to access them.
* src/raster/rastpic.c implement functions to allocate, destroy and
initialize PIC globals for raster renderer.
* src/raster/raster.c add new file to build: rastpic.c.
* src/raster/jamfile add new files to FT2_MULTI build: rastpic.c.
Horizontal_Gray_Sweep_Drop): Test for intersections which
degenerate to a single point can be ignored; this has been confirmed
by Greg Hitchcock from Microsoft. (This was commented out code.)
* src/raster/ftraster.c (Render_Glyph, Render_Gray_Glyph,
Draw_Sweep): No-dropout mode is value 2, not value 0.
(Draw_Sweep): Really skip dropout handling for no-dropout mode.
Pass dropout rules from the TT bytecode interpreter to the
rasterizer; temporarily this is enabled only if
`USE_SCAN_CONVERSION_RULES' is defined.
* include/freetype/ftimage.h (FT_OUTLINE_SMART_DROPOUTS,
FT_OUTLINE_EXCLUDE_STUBS): New flags for for FT_Outline.
* src/raster/ftraster.c (Vertical_Sweep_Drop, Horizontal_Sweep_Drop,
Horizontal_Gray_Sweep_Drop): Use same mode numbers as given in the
OpenType specification.
Fix mode 4 computation.
(Render_Glyph, Render_Gray_Glyph): Handle new outline flags.
* src/truetype/ttgload.c (TT_Load_Glyph)
[USE_SCAN_CONVERSION_RULES]: Convert scan conversion mode to
FT_OUTLINE_XXX flags.
* src/truetype/ttinterp.c (Ins_SCANCTRL): Enable ppem check.
compiled as stand-alone.
* src/raster/ftraster.c: Add comment how to compile as stand-alone.
s/FT_CONFIG_OPTION_STATIC_RASTER/FT_STATIC_RASTER/.
s/TT_STATIC_RASTER/FT_STATIC_RASTER/.
[_STANDALONE_]: Include ftimage.h and ftmisc.h.
(FT_TRACE1, FT_TRACE6, ft_memset, FT_MEM_ZERO): Define
conditionally.
(Render_Glyph, Render_Gray_Glyph): Return Raster_Err_None (or
Raster_Err_Unsupported).
(ft_black_new) [_STANDALONE_]: Fix type of `the_raster'.
(ft_black_init, ft_black_reset, ft_black_set_mode, ft_black_render):
Use `ras', not `raster'.
(ft_black_done): Use FT_UNUSED_RASTER.
(Horizontal_Sweep_Init, Horizontal_Sweep_Step,
Horizontal_Gray_Sweep_Span): Use FT_UNUSED_RASTER.
* docs/CHANGES: Updated.
Exclude debug info for `Release' versions to reduce library size.
* src/base/ftobjs.c (FT_Open_Face): Make it work as documented, this
is, ignore `aface' completely if face_index < 0. Reported by David
Osborn <spam@habitualhiatus.com>.
* include/freetype/ftimage.h (FT_Outline_MoveToFunc,
FT_Outline_LineTo_Func, FT_Outline_ConicToFunc,
FT_Outline_CubicToFunc), src/smooth/ftgrays.c (gray_render_conic,
gray_render_cubic, gray_move_to, gray_line_to, gray_conic_to,
gray_cubic_to, gray_render_span, gray_sweep): Decorate parameters
with `const' where appropriate.
Werner Lemberg