Previously, it was a float32, which obviously has 32 bits of state. Not
all of that 32 bit state space is meaningful, since NaN has multiple bit
representations. The underlying file format field (of type "Fixed" or
16.16 fixed point) is also 32 bits of state
(https://docs.microsoft.com/en-us/typography/opentype/spec/post).
Therefore, converting from 32 bit fixed point to 32 bit floating point
can be lossy. Instead, use 64 bit floating point. 53 significand bits
can losslessly represent all possible 16.16 fixed point values.
Using float64 is also arguably more Go-like, as the default type for the
ideal constant 0.5 is float64, not float32.
Change-Id: I5abe7979a020af2ac4784d6c2723ab8e39e38e34
Reviewed-on: https://go-review.googlesource.com/c/149837
Reviewed-by: Denys Smirnov <denis.smirnov.91@gmail.com>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Currently the library only parses the version in PostScript table.
However use cases such as PDF document processing requires this
information to be exposed.
CL parses a minimal set of the fields from the PostScript table
and exposes it via new PostTable method.
Change-Id: Ia86eecea9f5aaf557c7e4737f2474966aa30cff2
Reviewed-on: https://go-review.googlesource.com/c/145797
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Currently, the library produces a parsing error when the font
contains a PostScript table of version 1.0.
CL adds this version to the validation code and implements a glyph
name lookup for it.
Change-Id: Id4999d8b252e5c2d8e897f637ba31270336cfe9a
Reviewed-on: https://go-review.googlesource.com/c/146080
Reviewed-by: Nigel Tao <nigeltao@golang.org>
The library assumes the hmtx size to be equal to 2*nGlyph + 2*nHm,
which is a simplification of 4*nHm + 2*(nGlyph-nHm) as described
in the spec. However, fonts seen in the wild sometimes omit the
second term (left side bearings), making validation to fail.
CL fixes the validation code by allowing to omit the second term.
Fixesgolang/go#28379
Change-Id: I2293e498e72f95e5fe08c2b375ea7b020d06cde3
Reviewed-on: https://go-review.googlesource.com/c/144080
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Library assumes that OS/2 header size is at least 96 bytes,
which is not the case for fonts with OS/2 table version <= 1.
This CL adds a version test and handles the legacy header.
Fixesgolang/go#28339
Change-Id: I79bd8f8bbf262c1caaf4e66888446159b5e4fb43
Reviewed-on: https://go-review.googlesource.com/c/144079
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Reviewed-by: Elias Naur <elias.naur@gmail.com>
Also add tests for the Noto proprietary fonts. Prior to this commit,
NotoColorEmoji.ttf was unsupported. It's still not well supported, but
the error message returned is now more informative.
Change-Id: I61a3301d7f2458a4b838eb1de7a73d6472e3486f
Reviewed-on: https://go-review.googlesource.com/43694
Reviewed-by: David Crawshaw <crawshaw@golang.org>
A future commit will actually use subtables past the first one, but for
now, ignore them instead of failing on their presence.
Also add tests for the DejaVu proprietary fonts. Prior to this commit,
DejaVuSans-ExtraLight.ttf was unsupported.
Change-Id: Ic78a59c5ab30e4091efa2a04b89b12cb786157db
Reviewed-on: https://go-review.googlesource.com/42192
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The underlying font format's Y axis increases up. The Go standard
graphics libraries' Y axis increases down. This change makes the Go API
consistent with the other Go libraries.
Also change Segment.Args from [6]fixed.Int26_6 to [3]fixed.Point26_6 to
emphasize that the Args are consistent with other fixed.Point26_6 use.
Change-Id: Idd7b89eb4d86890dea477ac2ef96ff8f6b1dee8d
Reviewed-on: https://go-review.googlesource.com/39072
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The format is relatively complicated but rarely seen. It doesn't seem
worth the effort. Ignoring it is what Microsoft Windows and FreeType do.
Change-Id: I4415bd591c832650066de1d4e035b20a7230a4da
Reviewed-on: https://go-review.googlesource.com/38273
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Also add tests for Apple proprietary fonts.
Change-Id: I5ce8efa2397bb01c5255d956a77c955ba1383105
Reviewed-on: https://go-review.googlesource.com/38272
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This lets us load a glyph at e.g. 12 pixels per em.
Change-Id: I048b3db89af8670782953a8361afe0e6373df9b0
Reviewed-on: https://go-review.googlesource.com/37175
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This is based on the post table in the sfnt file.
Change-Id: I11f7a9bd9024cfc8f92adc5abb4d5356521f0df7
Reviewed-on: https://go-review.googlesource.com/36972
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Two recent commits ("proprietary fonts" and "cmap format 12") each
passed all of its own tests, but the combination wasn't tested until
both were submitted.
Change-Id: Ic4c2ae8deb1e4623ca5543672dc46d55bfce91a4
Reviewed-on: https://go-review.googlesource.com/36372
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Also make all of the Buffer fields non-exported. LoadGlyph now returns
the segments instead of setting Buffer.Segments for the caller to use.
Change-Id: I3f87070da5e8f014f88dbca70b62a4cd30e3fd66
Reviewed-on: https://go-review.googlesource.com/34532
Reviewed-by: Dave Day <djd@golang.org>
Parsing the per-glyph Charstrings will be a follow-up commit.
Change-Id: I52f849a77dd7fa14b6e07420820bdfb4347c2438
Reviewed-on: https://go-review.googlesource.com/33593
Reviewed-by: Dave Day <djd@golang.org>
