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gfxFT2Utils.h (2552B)


      1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
      2 * This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #ifndef GFX_FT2UTILS_H
      7 #define GFX_FT2UTILS_H
      8 
      9 #include "cairo-ft.h"
     10 #include "gfxFT2FontBase.h"
     11 
     12 // Rounding and truncation functions for a FreeType fixed point number
     13 // (FT26Dot6) stored in a 32bit integer with high 26 bits for the integer
     14 // part and low 6 bits for the fractional part.
     15 #define FLOAT_FROM_26_6(x) ((x) / 64.0)
     16 #define FLOAT_FROM_16_16(x) ((x) / 65536.0)
     17 #define ROUND_26_6_TO_INT(x) ((x) >= 0 ? ((32 + (x)) >> 6) : -((32 - (x)) >> 6))
     18 
     19 typedef struct FT_FaceRec_* FT_Face;
     20 
     21 /**
     22 * BEWARE: Recursively locking with gfxFT2LockedFace is not supported.
     23 * Do not instantiate gfxFT2LockedFace within the scope of another instance.
     24 * Do not attempt to call into Cairo within the scope of gfxFT2LockedFace,
     25 * as that may accidentally try to re-lock the face within Cairo itself
     26 * and thus deadlock.
     27 */
     28 class MOZ_STACK_CLASS gfxFT2LockedFace {
     29 public:
     30  explicit gfxFT2LockedFace(const gfxFT2FontBase* aFont)
     31      : mGfxFont(aFont), mFace(aFont->LockFTFace()) {}
     32  ~gfxFT2LockedFace() {
     33    if (mFace) {
     34      mGfxFont->UnlockFTFace();
     35    }
     36  }
     37 
     38  FT_Face get() { return mFace; };
     39 
     40  /**
     41   * Get the glyph id for a Unicode character representable by a single
     42   * glyph, or return zero if there is no such glyph.  This does no caching,
     43   * so you probably want gfxFcFont::GetGlyph.
     44   */
     45  uint32_t GetGlyph(uint32_t aCharCode);
     46  /**
     47   * Returns 0 if there is no variation selector cmap subtable.
     48   */
     49  uint32_t GetUVSGlyph(uint32_t aCharCode, uint32_t aVariantSelector);
     50 
     51 protected:
     52  typedef FT_UInt (*CharVariantFunction)(FT_Face face, FT_ULong charcode,
     53                                         FT_ULong variantSelector);
     54  CharVariantFunction FindCharVariantFunction();
     55 
     56  const gfxFT2FontBase* MOZ_NON_OWNING_REF mGfxFont;  // owned by caller
     57  FT_Face mFace;
     58 };
     59 
     60 // A couple of FreeType-based utilities shared by gfxFontconfigFontEntry
     61 // and FT2FontEntry.
     62 
     63 typedef struct FT_MM_Var_ FT_MM_Var;
     64 
     65 class gfxFT2Utils {
     66 public:
     67  static void GetVariationAxes(const FT_MM_Var* aMMVar,
     68                               nsTArray<gfxFontVariationAxis>& aAxes);
     69 
     70  static void GetVariationInstances(
     71      gfxFontEntry* aFontEntry, const FT_MM_Var* aMMVar,
     72      nsTArray<gfxFontVariationInstance>& aInstances);
     73 };
     74 
     75 #endif /* GFX_FT2UTILS_H */