From a53818a10b821218b86478e048a3884db93f7c00 Mon Sep 17 00:00:00 2001 From: Chris Loer Date: Fri, 15 Dec 2017 09:08:20 -0800 Subject: [core] Enable local glyph generation using TinySDF. - Platform-specific LocalGlyphRasterizer is responsible for deciding which glyphs to rasterize locally and for implementing the rasterization. - Default platform implementation doesn't locally generate any glyphs -> no behavior change - Unit test uses StubLocalGlyphRasterizer, which returns a single fixed bitmap for all CJK glyphs - Rename glyph_loader.test to glyph_manager.test --- src/mbgl/text/glyph_manager.cpp | 21 +++++++++++++--- src/mbgl/text/glyph_manager.hpp | 9 +++++-- src/mbgl/text/local_glyph_rasterizer.hpp | 42 ++++++++++++++++++++++++++++++++ 3 files changed, 66 insertions(+), 6 deletions(-) create mode 100644 src/mbgl/text/local_glyph_rasterizer.hpp (limited to 'src/mbgl') diff --git a/src/mbgl/text/glyph_manager.cpp b/src/mbgl/text/glyph_manager.cpp index 916d39ae62..59b019b547 100644 --- a/src/mbgl/text/glyph_manager.cpp +++ b/src/mbgl/text/glyph_manager.cpp @@ -4,14 +4,16 @@ #include #include #include +#include namespace mbgl { static GlyphManagerObserver nullObserver; -GlyphManager::GlyphManager(FileSource& fileSource_) +GlyphManager::GlyphManager(FileSource& fileSource_, std::unique_ptr localGlyphRasterizer_) : fileSource(fileSource_), - observer(&nullObserver) { + observer(&nullObserver), + localGlyphRasterizer(std::move(localGlyphRasterizer_)) { } GlyphManager::~GlyphManager() = default; @@ -30,7 +32,13 @@ void GlyphManager::getGlyphs(GlyphRequestor& requestor, GlyphDependencies glyphD const GlyphIDs& glyphIDs = dependency.second; GlyphRangeSet ranges; for (const auto& glyphID : glyphIDs) { - ranges.insert(getGlyphRange(glyphID)); + if (localGlyphRasterizer->canRasterizeGlyph(fontStack, glyphID)) { + if (entry.glyphs.find(glyphID) == entry.glyphs.end()) { + entry.glyphs.emplace(glyphID, makeMutable(generateLocalSDF(fontStack, glyphID))); + } + } else { + ranges.insert(getGlyphRange(glyphID)); + } } for (const auto& range : ranges) { @@ -49,9 +57,14 @@ void GlyphManager::getGlyphs(GlyphRequestor& requestor, GlyphDependencies glyphD } } +Glyph GlyphManager::generateLocalSDF(const FontStack& fontStack, GlyphID glyphID) { + Glyph local = localGlyphRasterizer->rasterizeGlyph(fontStack, glyphID); + local.bitmap = util::transformRasterToSDF(local.bitmap, 8, .25); + return local; +} + GlyphManager::GlyphRequest& GlyphManager::requestRange(Entry& entry, const FontStack& fontStack, const GlyphRange& range) { GlyphRequest& request = entry.ranges[range]; - if (request.req) { return request; } diff --git a/src/mbgl/text/glyph_manager.hpp b/src/mbgl/text/glyph_manager.hpp index 00df079462..13a8c07429 100644 --- a/src/mbgl/text/glyph_manager.hpp +++ b/src/mbgl/text/glyph_manager.hpp @@ -3,6 +3,7 @@ #include #include #include +#include #include #include #include @@ -24,7 +25,7 @@ public: class GlyphManager : public util::noncopyable { public: - GlyphManager(FileSource&); + GlyphManager(FileSource&, std::unique_ptr = std::make_unique()); ~GlyphManager(); // Workers send a `getGlyphs` message to the main thread once they have determined @@ -42,6 +43,8 @@ public: void setObserver(GlyphManagerObserver*); private: + Glyph generateLocalSDF(const FontStack& fontStack, GlyphID glyphID); + FileSource& fileSource; std::string glyphURL; @@ -61,8 +64,10 @@ private: GlyphRequest& requestRange(Entry&, const FontStack&, const GlyphRange&); void processResponse(const Response&, const FontStack&, const GlyphRange&); void notify(GlyphRequestor&, const GlyphDependencies&); - + GlyphManagerObserver* observer = nullptr; + + std::unique_ptr localGlyphRasterizer; }; } // namespace mbgl diff --git a/src/mbgl/text/local_glyph_rasterizer.hpp b/src/mbgl/text/local_glyph_rasterizer.hpp new file mode 100644 index 0000000000..c2bdbd2840 --- /dev/null +++ b/src/mbgl/text/local_glyph_rasterizer.hpp @@ -0,0 +1,42 @@ +#pragma once + +#include + +namespace mbgl { + +/* + Given a font stack and a glyph ID, platform-specific implementations of + LocalGlyphRasterizer will decide which, if any, local fonts to use and + then generate a matching glyph object with a greyscale rasterization of + the glyph and appropriate metrics. GlyphManager will then use TinySDF to + transform the rasterized bitmap into an SDF. + + The JS equivalent of this functionality will only generate glyphs in the + 'CJK Unified Ideographs' and 'Hangul Syllables' ranges, for which it can + get away with rendering a fixed 30px square image and GlyphMetrics of: + + width: 24, + height: 24, + left: 0, + top: -8, + advance: 24 + + The JS equivalent also uses heuristic evaluation of the font stack name + to control the font-weight it uses during rasterization. + + It is left to platform-specific implementation to decide how best to + map a FontStack to a particular rasterization. + + The default implementation simply refuses to rasterize any glyphs. +*/ + +class LocalGlyphRasterizer { +public: + virtual ~LocalGlyphRasterizer() = default; + + // virtual so that test harness can override platform-specific behavior + virtual bool canRasterizeGlyph(const FontStack&, GlyphID); + virtual Glyph rasterizeGlyph(const FontStack&, GlyphID); +}; + +} // namespace mbgl -- cgit v1.2.1