Empty input was asserting originally, but such strict behavior doesn't
seem to be useful in practice as all application code would need to
explicitly make sure that shape() isn't called if the input or the input
range is empty. In particular, I hit this assert as soon as I rebuilt
and ran magnum-player, and the assertion didn't really uncover any bug
or make anything better by firing.
Treating zero glyph output as a failure also isn't good -- rendering
for example a string of whitespace may also result in zero glyphs on the
output, which isn't a failure. Plus it's currently unclear what should
actually be a failure -- neither FreeType nor HarfBuzz really have a
concept of the shaping operation failing, hb_shape() returns void -- so
special-casing glyphCount() being zero as a failure just doesn't make
sense.
This thus means the doScript(), doLanguage() and doDirection()
implementations are now called always, regardless of whether shape() was
called at all, or whether it produced any glyphs. This allows the shaper
for example to give back a detected script etc even if the actual
input range to shape was empty.
This class won't print the deprecation warning in that case. I'm a bit
disappointed that the Clang changelogs are always so vague, there's
often never a possibility to figure out which version a particular bug
was fixed in apart from testing each and every.
Replaces the previous, grossly inefficient AbstractLayouter which was
performing one virtual call per glyph (!). It's now also reusable,
meaning it doesn't need to be allocated anew for every new shaped text,
and it no longer requires each and every font plugin to implement the
same redundant glyph data fetching from the glyph cache, scaling etc. --
all that is meant to be done by the users of AbstractShaper, i.e.
Renderer. The independency on a glyph cache theorerically also means it
can be used for a completely different, non-texture-based way to render
text (such as direct path drawing directly on the GPU), although I won't
be exploring that path now.
It also exposes an interface for specifying script, language,
direction and typographic features. Such interface will be currently
only implemented in HarfBuzz, but that's the intent -- to provide a
flexible enough interface to support all possible use cases that a font
or a font plugin may support, instead of exposing a least common
denominator and then having no easy way to shape a text in a non-Latin
script or use a fancy OpenType feature the chosen font has.
The old public interface is preserved for backwards compatibility,
marked as deprecated, however the virtual APIs are not, as supporting
that would be too nasty. I don't think any user code ever implemented a
font plugin so this should be okay.
To ensure smooth transition with no regressions, the Renderer class and
MagnumFont tests still use the old API in this commit, and their test
pass the same way as they did before (except for two removed MagnumFont
test cases which tested errors that are now an assertion in the
deprecated layout() API and thus cannot be tested from the plugin
anymore). Porting them away from the deprecated API will be done in
separate commits.
Will be used for the upcoming new AbstractShaper API. It's based on the
ISO script codes, matching the HarfBuzz script enum, with the intention
of being passed to it as-is.
It doesn't need to access anything else than what the base API provides,
doesn't render with it, and doesn't expose the instance via any getter
either.
Even though the Renderer is scheduled for a total rework and changing
the old API may feel like throwaway work, this change alone doesn't
break anything and allows me to test certain new corner cases.
It was all just way too random and completely detached from real-world
cases. In particular, the mesh rectangle and the texture rectangle were
completely different, which just cannot happen, and was completely
disregarding presence of a glyph cache, making it impossible to adapt to
the upcoming AbstractLayouter / AbstractShaper rework.
It now also explicitly verifies behavior of various Alignment values
instead of just testing them at random, and there's also a new TODO
related to those.
And thus the DistanceFieldGlyphCache subclass as well. The
deinlined destructor wasn't really needed as the GL::Texture has its
destructor deinlined as well, so it wouldn't cause too much extra work
for the compiler to have it implicit.
Also, I suspect the destructor was just a leftover from when there was
no AbstractGlyphCache base.
The class now supports incremental filling, multiple fonts, texture
arrays, removes all reliance on STL containers and is finally properly
documented.
To avoid complete breakage of every use, as much as possible was kept as
deprecated APIs -- in particular the reserve() with the nasty
std::vectors, the insert() that assumes a 2D cache and a single font
and textureSize() that returns a 2D vector. Those behave the same as
before, but will assert if the cache is an array or contains more than
one font.
On the other hand, begin() / end() access with std::unordered_map iterators
(ew!) was removed as the internals simply aren't a hashmap anymore. The
image() that returned an Image2D is now used to fill the glyph cache
instead of querying its potentially processed contents, and returns a
MutableImageView3D. I considered keeping it and adding sourceImage()
instead, but such naming turned out to be too inconsistent. For querying
processed image data (such as with the distance field cache) there's a
new processedImage() query, guarded by new GlyphCacheFeature bits -- if
both ImageProcessing and ProcessedImageDownload is set, it can be used
to retrieve the processed image (so, similar as ImageDownload was
before), and if neither is set, the cache contents are queryable
directly through image(), without needing any special support from
the GPU API.
Existing code is updated only in the minimal way possible to ensure that
no serious breakage was introduced by reimplementing the deprecated APIs
on top of the new backend. Porting away from deprecated APIs will be
done in next commits. The GlyphCache and DistanceFieldGlyphCache have
their public API kept intact for now, as a similar rework will be needed
for them as well.
Additionally, the MagnumFont and MagnumFontConverter plugins aren't
compiling yet as they require substantial changes to deal with the new
glyph cache features. That is not the case with other plugins in the
magnum-plugins repository tho, for those the backwards compatibility
"just works". On the other hand, since layout of the AbstractGlyphChange
changed, I'm bumping the AbstractFont plugin interface version to
force-trigger a rebuild of dependent projects. Because I ran a stale
magnum-player binary, it worked without crashing or GL errors but just
didn't show ANY text whatsoever due to ABI differences, and I wasted
some precious minutes before realizing that a simple rebuild would fix
it.
Not yet the full extent of it including rotations and incremental
packing, as the existing interface is too awful, also patching over
zero-sized glyphs that the new packer doesn't like. Another round of
deprecations needs to happen first.
It won't contain just font metrics anymore. Also don't require the
struct to be zero-initialized if opening fails -- simply allow the
plugins to return garbage in that case and save the values only if
opening actually succeeded.
Strictly speaking this isn't an ABI change as the return value isn't
part of the function signature and the struct is still the same, so the
plugin interface version isn't bumped for this change.
All std::string arguments are now a StringView, what returned a
std::pair is now a Pair. STL compatibility headers are included on
deprecated builds to ease porting, as usual.
The only *really* breaking changes are in the internals, where an
ArrayView<const char32_t> is used instead of std::u32string, which is in
line with the change done in Utility::Unicode::utf32(); and a Triple is
returned instead of a std::tuple. Behaviorally nothing changed except
that fillGlyphCache() now asserts if the input string contains invalid
UTF-8 (which is also in line with the cahnge done in Utility::Unicode).
Not that C++ STL and exceptions would be anything to take inspiration
from, but there's std::out_of_range. Python IndexError is also specified
as "index out of range", not "bounds".
Partially needed to avoid build breakages because Corrade itself
switched as well, partially because a cleanup is always good. Done
except for (STL-heavy) code that's deprecated or SceneGraph-related APIs
that are still quite full of STL as well.
Such as Emscripten or Android. The hypothetical use case is converting
shader files directly on an Android device to debug things, or having a
Node.js build of a scene/image converter for "portability".
Static plugins can be linked to these if Magnum is built together with
Magnum Plugins in a CMake superproject and the plugins are then linked
via the MAGNUM_*CONVERTER_STATIC_PLUGINS CMake variable.
The fontconverter and distanceconverter tools cause a CMake error on
Emscripten as it's not currently possible to access the GPU through a
command-line Node.js app. On Android they work though.
About time this got done. This also has an XFAIL for the case where a
distance field image is processed with an offset, have to fix the
underlying issue in TextureTools first.
Also added a range assertion for the distance field image setter to
match what the abstract base does, together with a corresponding getter.
This means I (and people making their own plugins) don't need to go and
update each and every plugin once the version in the interface string
gets bumped after a (silent) ABI break. Such as when new virtual
functions get added, as those often lead to strange crashes if the
plugins don't get rebuilt after.
The plugins will now use this macro, which means they'll
automatically embed an interface string that was present in the base
class header at build time. However, when the base class updates, the
previous string is still embedded in the plugin binary, which will then
fail to load -- this being automatic doesn't mean the original purpose
is lost. Subsequently rebuilding the plugins from source will make them
pick up the updated interface string again.
Of course I used the wrong `CORRADE_FAIL_IF(false, ...)` in a few
places. Yet another confirmation it was too hard to use and a dedicated
macro is needed.
Funny/sad that this possibility took me so long to realize. Until now it
was "you can have command-line utilities or static plugins but never
both", and only with CMake 3.13+ it was possible to link static plugins
to these executables from outside. Now it's a builtin and supported
option.
For some reason, it was adding also the magnum / magnum-d directory,
which isn't really useful, especially in cases where the directory is
not at all or it's desired to pick a debug plugin from a release
executable and vice versa.
Also the distancefieldconverter was still attempting to join with an
absolute path -- somehow 7fb63a9434 missed
this one.
I really need to write regression tests for all this, sigh.
These two options were mutually exclusive, and both were doing the same
thing -- switching to EGL on desktop GL, or switching away from EGL on
GLES. That made all logic vastly more complicated than it should be, and
unfortunately it took me half a decade to realize that. The new logic is
significantly simpler everywhere.
As usual, the old options are still recognized by CMake on a deprecated
build (with a warning), and are still exposed both as CMake variables
and a preprocessor define. But the logic for them was quite complicated,
so I don't guarantee all cases are covered.
I also tried to clean up the dependent CMake options to allow building
GLX and WGL apps on GLES independently of whether EGL is used, but it's
quite a mess due to the limitations of CMake < 3.22. Build directories
that have the options switched randomly over a long time might start
misbehaving, but the initial build should work well.
The whole class was a bad idea, why create something that's 99% similar
to another application and has just one platform-specific workaround? Of
course it resulted in this code being completely untested and not even
built anywhere, because it served a tiny insignificant use case.
To avoid losing all the code, I did my best in attempting to merge this
into the WindowlessEglApplication. But since, again, EGL isn't
really used on any Windows platform, I can't even say it builds
properly. Maybe not even the original code built.
Vladimír Vondruš