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Text: new AbstractShaper interface for shaping. 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.
3 years ago
/*
This file is part of Magnum.
Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
2020, 2021, 2022, 2023 Vladimír Vondruš <mosra@centrum.cz>
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/
#include "AbstractShaper.h"
#include <Corrade/Containers/StridedArrayView.h>
#include <Corrade/Containers/StringView.h>
#include "Magnum/Text/Script.h"
namespace Magnum { namespace Text {
Debug& operator<<(Debug& debug, const Direction value) {
debug << "Text::Direction" << Debug::nospace;
switch(value) {
/* LCOV_EXCL_START */
#define _c(v) case Direction::v: return debug << "::" #v;
_c(Unspecified)
_c(LeftToRight)
_c(RightToLeft)
_c(TopToBottom)
_c(BottomToTop)
#undef _c
/* LCOV_EXCL_STOP */
}
return debug << "(" << Debug::nospace << reinterpret_cast<void*>(UnsignedByte(value)) << Debug::nospace << ")";
}
AbstractShaper::AbstractShaper(AbstractFont& font): _font(font), _glyphCount{0} {}
AbstractShaper::AbstractShaper(AbstractShaper&&) noexcept = default;
AbstractShaper::~AbstractShaper() = default;
AbstractShaper& AbstractShaper::operator=(AbstractShaper&&) noexcept = default;
bool AbstractShaper::setScript(const Script script) {
return doSetScript(script);
}
bool AbstractShaper::doSetScript(Script) { return false; }
bool AbstractShaper::setLanguage(const Containers::StringView language) {
return doSetLanguage(language);
}
bool AbstractShaper::doSetLanguage(Containers::StringView) { return false; }
bool AbstractShaper::setDirection(const Direction direction) {
return doSetDirection(direction);
}
bool AbstractShaper::doSetDirection(Direction) { return false; }
UnsignedInt AbstractShaper::shape(const Containers::StringView text, const UnsignedInt begin, const UnsignedInt end, const Containers::ArrayView<const FeatureRange> features) {
CORRADE_ASSERT((end == ~UnsignedInt{} && begin <= text.size()) ||
(begin <= end && end <= text.size()),
"Text::AbstractShaper::shape(): begin" << begin << "and end" << end << "out of range for a text of" << text.size() << "bytes", {});
CORRADE_ASSERT(begin < text.size() && begin != end,
"Text::AbstractShaper::shape(): shaped text at begin" << begin << "is empty", {});
#ifndef CORRADE_NO_ASSERT
for(std::size_t i = 0; i != features.size(); ++i) {
const FeatureRange& feature = features[i];
CORRADE_ASSERT(
(feature._end == ~UnsignedInt{} && feature._begin <= text.size()) ||
(feature._begin <= feature._end && feature._end <= text.size()),
"Text::AbstractShaper::shape(): feature" << i << "begin" << feature._begin << "and end" << feature._end << "out of range for a text of" << text.size() << "bytes", {});
/** @todo catch empty feature ranges too? or not important */
}
#endif
return _glyphCount = doShape(text, begin, end, features);
}
UnsignedInt AbstractShaper::shape(const Containers::StringView text, const UnsignedInt begin, const UnsignedInt end, const std::initializer_list<FeatureRange> features) {
return shape(text, begin, end, Containers::arrayView(features));
}
UnsignedInt AbstractShaper::shape(const Containers::StringView text, const UnsignedInt begin, const UnsignedInt end) {
return shape(text, begin, end, nullptr);
}
UnsignedInt AbstractShaper::shape(const Containers::StringView text, const Containers::ArrayView<const FeatureRange> features) {
return shape(text, 0, ~UnsignedInt{}, features);
}
UnsignedInt AbstractShaper::shape(const Containers::StringView text, const std::initializer_list<FeatureRange> features) {
return shape(text, Containers::arrayView(features));
}
UnsignedInt AbstractShaper::shape(const Containers::StringView text) {
return shape(text, nullptr);
}
Script AbstractShaper::script() const {
return _glyphCount ? doScript() : Script::Unspecified;
}
Script AbstractShaper::doScript() const { return Script::Unspecified; }
Containers::StringView AbstractShaper::language() const {
return _glyphCount ? doLanguage() : Containers::StringView{};
}
Containers::StringView AbstractShaper::doLanguage() const { return {}; }
Direction AbstractShaper::direction() const {
return _glyphCount ? doDirection() : Direction::Unspecified;
}
Direction AbstractShaper::doDirection() const { return Direction::Unspecified; }
void AbstractShaper::glyphsInto(const Containers::StridedArrayView1D<UnsignedInt>& ids, const Containers::StridedArrayView1D<Vector2>& offsets, const Containers::StridedArrayView1D<Vector2>& advances) const {
CORRADE_ASSERT(ids.size() == _glyphCount && offsets.size() == _glyphCount && advances.size() == _glyphCount,
"Text::AbstractShaper::glyphsInto(): expected the ids, offsets and advanced views to have a size of" << _glyphCount << "but got" << ids.size() << Debug::nospace << "," << offsets.size() << "and" << advances.size(), );
/* Call into the implementation only if there's actually anything shaped,
otherwise it might not yet have everything properly set up */
if(_glyphCount)
doGlyphsInto(ids, offsets, advances);
}
}}