/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef GFX_FT2UTILS_H #define GFX_FT2UTILS_H #include "cairo-ft.h" #include "gfxFT2FontBase.h" #include "mozilla/Likely.h" // Rounding and truncation functions for a FreeType fixed point number // (FT26Dot6) stored in a 32bit integer with high 26 bits for the integer // part and low 6 bits for the fractional part. #define FLOAT_FROM_26_6(x) ((x) / 64.0) #define FLOAT_FROM_16_16(x) ((x) / 65536.0) #define ROUND_26_6_TO_INT(x) ((x) >= 0 ? ((32 + (x)) >> 6) \ : -((32 - (x)) >> 6)) typedef struct FT_FaceRec_* FT_Face; class gfxFT2LockedFace { public: explicit gfxFT2LockedFace(gfxFT2FontBase *aFont) : mGfxFont(aFont), mFace(cairo_ft_scaled_font_lock_face(aFont->CairoScaledFont())) { } ~gfxFT2LockedFace() { if (mFace) { cairo_ft_scaled_font_unlock_face(mGfxFont->CairoScaledFont()); } } FT_Face get() { return mFace; }; /** * Get the glyph id for a Unicode character representable by a single * glyph, or return zero if there is no such glyph. This does no caching, * so you probably want gfxFcFont::GetGlyph. */ uint32_t GetGlyph(uint32_t aCharCode); /** * Returns 0 if there is no variation selector cmap subtable. */ uint32_t GetUVSGlyph(uint32_t aCharCode, uint32_t aVariantSelector); void GetMetrics(gfxFont::Metrics* aMetrics, uint32_t* aSpaceGlyph); // A scale factor for use in converting horizontal metrics from font units // to pixels. gfxFloat XScale() { if (MOZ_UNLIKELY(!mFace)) return 0.0; const FT_Size_Metrics& ftMetrics = mFace->size->metrics; if (FT_IS_SCALABLE(mFace)) { // Prefer FT_Size_Metrics::x_scale to x_ppem as x_ppem does not // have subpixel accuracy. // // FT_Size_Metrics::x_scale is in 16.16 fixed point format. Its // (fractional) value is a factor that converts vertical metrics // from design units to units of 1/64 pixels, so that the result // may be interpreted as pixels in 26.6 fixed point format. return FLOAT_FROM_26_6(FLOAT_FROM_16_16(ftMetrics.x_scale)); } // Not scalable. // FT_Size_Metrics doc says x_scale is "only relevant for scalable // font formats". return gfxFloat(ftMetrics.x_ppem) / gfxFloat(mFace->units_per_EM); } protected: /** * Get extents for a simple character representable by a single glyph. * The return value is the glyph id of that glyph or zero if no such glyph * exists. aExtents is only set when this returns a non-zero glyph id. */ uint32_t GetCharExtents(char aChar, cairo_text_extents_t* aExtents); typedef FT_UInt (*CharVariantFunction)(FT_Face face, FT_ULong charcode, FT_ULong variantSelector); CharVariantFunction FindCharVariantFunction(); RefPtr<gfxFT2FontBase> mGfxFont; FT_Face mFace; }; #endif /* GFX_FT2UTILS_H */