gfx/thebes/gfxFT2Utils.h@97036ab72558 (annotated)
gfx/thebes/gfxFT2Utils.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- |
| michael@0 | 2 | * This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | #ifndef GFX_FT2UTILS_H |
| michael@0 | 7 | #define GFX_FT2UTILS_H |
| michael@0 | 8 | |
| michael@0 | 9 | #include "cairo-ft.h" |
| michael@0 | 10 | #include "gfxFT2FontBase.h" |
| michael@0 | 11 | #include "mozilla/Likely.h" |
| michael@0 | 12 | |
| michael@0 | 13 | // Rounding and truncation functions for a FreeType fixed point number |
| michael@0 | 14 | // (FT26Dot6) stored in a 32bit integer with high 26 bits for the integer |
| michael@0 | 15 | // part and low 6 bits for the fractional part. |
| michael@0 | 16 | #define FLOAT_FROM_26_6(x) ((x) / 64.0) |
| michael@0 | 17 | #define FLOAT_FROM_16_16(x) ((x) / 65536.0) |
| michael@0 | 18 | #define ROUND_26_6_TO_INT(x) ((x) >= 0 ? ((32 + (x)) >> 6) \ |
| michael@0 | 19 | : -((32 - (x)) >> 6)) |
| michael@0 | 20 | |
| michael@0 | 21 | typedef struct FT_FaceRec_* FT_Face; |
| michael@0 | 22 | |
| michael@0 | 23 | class gfxFT2LockedFace { |
| michael@0 | 24 | public: |
| michael@0 | 25 | gfxFT2LockedFace(gfxFT2FontBase *aFont) : |
| michael@0 | 26 | mGfxFont(aFont), |
| michael@0 | 27 | mFace(cairo_ft_scaled_font_lock_face(aFont->CairoScaledFont())) |
| michael@0 | 28 | { } |
| michael@0 | 29 | ~gfxFT2LockedFace() |
| michael@0 | 30 | { |
| michael@0 | 31 | if (mFace) { |
| michael@0 | 32 | cairo_ft_scaled_font_unlock_face(mGfxFont->CairoScaledFont()); |
| michael@0 | 33 | } |
| michael@0 | 34 | } |
| michael@0 | 35 | |
| michael@0 | 36 | FT_Face get() { return mFace; }; |
| michael@0 | 37 | |
| michael@0 | 38 | /** |
| michael@0 | 39 | * Get the glyph id for a Unicode character representable by a single |
| michael@0 | 40 | * glyph, or return zero if there is no such glyph. This does no caching, |
| michael@0 | 41 | * so you probably want gfxFcFont::GetGlyph. |
| michael@0 | 42 | */ |
| michael@0 | 43 | uint32_t GetGlyph(uint32_t aCharCode); |
| michael@0 | 44 | /** |
| michael@0 | 45 | * Returns 0 if there is no variation selector cmap subtable. |
| michael@0 | 46 | */ |
| michael@0 | 47 | uint32_t GetUVSGlyph(uint32_t aCharCode, uint32_t aVariantSelector); |
| michael@0 | 48 | |
| michael@0 | 49 | void GetMetrics(gfxFont::Metrics* aMetrics, uint32_t* aSpaceGlyph); |
| michael@0 | 50 | |
| michael@0 | 51 | // A scale factor for use in converting horizontal metrics from font units |
| michael@0 | 52 | // to pixels. |
| michael@0 | 53 | gfxFloat XScale() |
| michael@0 | 54 | { |
| michael@0 | 55 | if (MOZ_UNLIKELY(!mFace)) |
| michael@0 | 56 | return 0.0; |
| michael@0 | 57 | |
| michael@0 | 58 | const FT_Size_Metrics& ftMetrics = mFace->size->metrics; |
| michael@0 | 59 | |
| michael@0 | 60 | if (FT_IS_SCALABLE(mFace)) { |
| michael@0 | 61 | // Prefer FT_Size_Metrics::x_scale to x_ppem as x_ppem does not |
| michael@0 | 62 | // have subpixel accuracy. |
| michael@0 | 63 | // |
| michael@0 | 64 | // FT_Size_Metrics::x_scale is in 16.16 fixed point format. Its |
| michael@0 | 65 | // (fractional) value is a factor that converts vertical metrics |
| michael@0 | 66 | // from design units to units of 1/64 pixels, so that the result |
| michael@0 | 67 | // may be interpreted as pixels in 26.6 fixed point format. |
| michael@0 | 68 | return FLOAT_FROM_26_6(FLOAT_FROM_16_16(ftMetrics.x_scale)); |
| michael@0 | 69 | } |
| michael@0 | 70 | |
| michael@0 | 71 | // Not scalable. |
| michael@0 | 72 | // FT_Size_Metrics doc says x_scale is "only relevant for scalable |
| michael@0 | 73 | // font formats". |
| michael@0 | 74 | return gfxFloat(ftMetrics.x_ppem) / gfxFloat(mFace->units_per_EM); |
| michael@0 | 75 | } |
| michael@0 | 76 | |
| michael@0 | 77 | protected: |
| michael@0 | 78 | /** |
| michael@0 | 79 | * Get extents for a simple character representable by a single glyph. |
| michael@0 | 80 | * The return value is the glyph id of that glyph or zero if no such glyph |
| michael@0 | 81 | * exists. aExtents is only set when this returns a non-zero glyph id. |
| michael@0 | 82 | */ |
| michael@0 | 83 | uint32_t GetCharExtents(char aChar, cairo_text_extents_t* aExtents); |
| michael@0 | 84 | |
| michael@0 | 85 | typedef FT_UInt (*CharVariantFunction)(FT_Face face, |
| michael@0 | 86 | FT_ULong charcode, |
| michael@0 | 87 | FT_ULong variantSelector); |
| michael@0 | 88 | CharVariantFunction FindCharVariantFunction(); |
| michael@0 | 89 | |
| michael@0 | 90 | nsRefPtr<gfxFT2FontBase> mGfxFont; |
| michael@0 | 91 | FT_Face mFace; |
| michael@0 | 92 | }; |
| michael@0 | 93 | |
| michael@0 | 94 | #endif /* GFX_FT2UTILS_H */ |
