diff options
Diffstat (limited to 'platform/android/src/text/local_glyph_rasterizer.cpp')
-rw-r--r-- | platform/android/src/text/local_glyph_rasterizer.cpp | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/platform/android/src/text/local_glyph_rasterizer.cpp b/platform/android/src/text/local_glyph_rasterizer.cpp new file mode 100644 index 0000000000..ce1b0fc8fd --- /dev/null +++ b/platform/android/src/text/local_glyph_rasterizer.cpp @@ -0,0 +1,126 @@ +#include <mbgl/text/local_glyph_rasterizer.hpp> +#include <mbgl/util/i18n.hpp> +#include <mbgl/util/platform.hpp> + +#include <jni/jni.hpp> + +#include "../attach_env.hpp" +#include "../bitmap.hpp" + +#include "local_glyph_rasterizer_jni.hpp" + +/* + Android implementation of LocalGlyphRasterizer: + Draws CJK glyphs using locally available fonts. + + Follows pattern of GL JS implementation in that: + - Only CJK glyphs are drawn locally (because we can guess their metrics effectively) + * Render size/metrics determined experimentally using Noto Sans + - Configuration is done at map creation time by setting a "font family" + * JS uses a CSS font-family, this uses android.graphics.Typeface + https://developer.android.com/reference/android/graphics/Typeface.html + - We use heuristics to extract a font-weight based on the incoming font stack + * JS tries to extract multiple weights, this implementation only looks for + "bold" + + mbgl::LocalGlyphRasterizer is the portable interface + mbgl::LocalGlyphRasterizer::Impl stores platform-specific configuration data + mbgl::android::LocalGlyphRasterizer is the JNI wrapper + com.mapbox.mapboxsdk.text.LocalGlyphRasterizer is the Java implementation that + actually does the drawing + */ + +namespace mbgl { +namespace android { + +PremultipliedImage LocalGlyphRasterizer::drawGlyphBitmap(const std::string& fontFamily, const bool bold, const GlyphID glyphID) { + UniqueEnv env { AttachEnv() }; + + using Signature = jni::Object<Bitmap>(jni::String, jni::jboolean, jni::jchar); + auto method = javaClass.GetStaticMethod<Signature>(*env, "drawGlyphBitmap"); + + jni::String jniFontFamily = jni::Make<jni::String>(*env, fontFamily); + + auto javaBitmap = javaClass.Call(*env, + method, + jniFontFamily, + static_cast<jni::jboolean>(bold), + static_cast<jni::jchar>(glyphID)); + + PremultipliedImage result = Bitmap::GetImage(*env, javaBitmap); + jni::DeleteLocalRef(*env, javaBitmap); + return result; +} + +void LocalGlyphRasterizer::registerNative(jni::JNIEnv& env) { + javaClass = *jni::Class<LocalGlyphRasterizer>::Find(env).NewGlobalRef(env).release(); +} + +jni::Class<LocalGlyphRasterizer> LocalGlyphRasterizer::javaClass; + +} // namespace android + +class LocalGlyphRasterizer::Impl { +public: + Impl(const optional<std::string> fontFamily_) + : fontFamily(fontFamily_) + {} + + bool isConfigured() const { + return bool(fontFamily); + } + + PremultipliedImage drawGlyphBitmap(const FontStack& fontStack, GlyphID glyphID) { + bool bold = false; + for (auto font : fontStack) { + std::string lowercaseFont = platform::lowercase(font); + if (lowercaseFont.find("bold") != std::string::npos) { + bold = true; + } + } + return android::LocalGlyphRasterizer::drawGlyphBitmap(*fontFamily, bold, glyphID); + } + +private: + optional<std::string> fontFamily; +}; + +LocalGlyphRasterizer::LocalGlyphRasterizer(const optional<std::string> fontFamily) + : impl(std::make_unique<Impl>(fontFamily)) +{} + +LocalGlyphRasterizer::~LocalGlyphRasterizer() +{} + +bool LocalGlyphRasterizer::canRasterizeGlyph(const FontStack&, GlyphID glyphID) { + return util::i18n::allowsFixedWidthGlyphGeneration(glyphID) && impl->isConfigured(); +} + +Glyph LocalGlyphRasterizer::rasterizeGlyph(const FontStack& fontStack, GlyphID glyphID) { + Glyph fixedMetrics; + if (!impl->isConfigured()) { + return fixedMetrics; + } + + fixedMetrics.id = glyphID; + + Size size(35, 35); + + fixedMetrics.metrics.width = size.width; + fixedMetrics.metrics.height = size.height; + fixedMetrics.metrics.left = 3; + fixedMetrics.metrics.top = -10; + fixedMetrics.metrics.advance = 24; + + PremultipliedImage rgbaBitmap = impl->drawGlyphBitmap(fontStack, glyphID); + + // Copy alpha values from RGBA bitmap into the AlphaImage output + fixedMetrics.bitmap = AlphaImage(size); + for (uint32_t i = 0; i < size.width * size.height; i++) { + fixedMetrics.bitmap.data[i] = rgbaBitmap.data[4 * i + 3]; + } + + return fixedMetrics; +} + +} // namespace mbgl |