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Author	SHA1	Message	Date
Vladimír Vondruš	ab8dc070c4	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

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Vladimír Vondruš

ab8dc070c4

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

1 Commits (3c394532edc282080ebc7d7fd8cc60bf0c10fb23)