1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/thebes/gfxFT2Utils.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,94 @@
1.4 +/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef GFX_FT2UTILS_H
1.10 +#define GFX_FT2UTILS_H
1.11 +
1.12 +#include "cairo-ft.h"
1.13 +#include "gfxFT2FontBase.h"
1.14 +#include "mozilla/Likely.h"
1.15 +
1.16 +// Rounding and truncation functions for a FreeType fixed point number
1.17 +// (FT26Dot6) stored in a 32bit integer with high 26 bits for the integer
1.18 +// part and low 6 bits for the fractional part.
1.19 +#define FLOAT_FROM_26_6(x) ((x) / 64.0)
1.20 +#define FLOAT_FROM_16_16(x) ((x) / 65536.0)
1.21 +#define ROUND_26_6_TO_INT(x) ((x) >= 0 ? ((32 + (x)) >> 6) \
1.22 + : -((32 - (x)) >> 6))
1.23 +
1.24 +typedef struct FT_FaceRec_* FT_Face;
1.25 +
1.26 +class gfxFT2LockedFace {
1.27 +public:
1.28 + gfxFT2LockedFace(gfxFT2FontBase *aFont) :
1.29 + mGfxFont(aFont),
1.30 + mFace(cairo_ft_scaled_font_lock_face(aFont->CairoScaledFont()))
1.31 + { }
1.32 + ~gfxFT2LockedFace()
1.33 + {
1.34 + if (mFace) {
1.35 + cairo_ft_scaled_font_unlock_face(mGfxFont->CairoScaledFont());
1.36 + }
1.37 + }
1.38 +
1.39 + FT_Face get() { return mFace; };
1.40 +
1.41 + /**
1.42 + * Get the glyph id for a Unicode character representable by a single
1.43 + * glyph, or return zero if there is no such glyph. This does no caching,
1.44 + * so you probably want gfxFcFont::GetGlyph.
1.45 + */
1.46 + uint32_t GetGlyph(uint32_t aCharCode);
1.47 + /**
1.48 + * Returns 0 if there is no variation selector cmap subtable.
1.49 + */
1.50 + uint32_t GetUVSGlyph(uint32_t aCharCode, uint32_t aVariantSelector);
1.51 +
1.52 + void GetMetrics(gfxFont::Metrics* aMetrics, uint32_t* aSpaceGlyph);
1.53 +
1.54 + // A scale factor for use in converting horizontal metrics from font units
1.55 + // to pixels.
1.56 + gfxFloat XScale()
1.57 + {
1.58 + if (MOZ_UNLIKELY(!mFace))
1.59 + return 0.0;
1.60 +
1.61 + const FT_Size_Metrics& ftMetrics = mFace->size->metrics;
1.62 +
1.63 + if (FT_IS_SCALABLE(mFace)) {
1.64 + // Prefer FT_Size_Metrics::x_scale to x_ppem as x_ppem does not
1.65 + // have subpixel accuracy.
1.66 + //
1.67 + // FT_Size_Metrics::x_scale is in 16.16 fixed point format. Its
1.68 + // (fractional) value is a factor that converts vertical metrics
1.69 + // from design units to units of 1/64 pixels, so that the result
1.70 + // may be interpreted as pixels in 26.6 fixed point format.
1.71 + return FLOAT_FROM_26_6(FLOAT_FROM_16_16(ftMetrics.x_scale));
1.72 + }
1.73 +
1.74 + // Not scalable.
1.75 + // FT_Size_Metrics doc says x_scale is "only relevant for scalable
1.76 + // font formats".
1.77 + return gfxFloat(ftMetrics.x_ppem) / gfxFloat(mFace->units_per_EM);
1.78 + }
1.79 +
1.80 +protected:
1.81 + /**
1.82 + * Get extents for a simple character representable by a single glyph.
1.83 + * The return value is the glyph id of that glyph or zero if no such glyph
1.84 + * exists. aExtents is only set when this returns a non-zero glyph id.
1.85 + */
1.86 + uint32_t GetCharExtents(char aChar, cairo_text_extents_t* aExtents);
1.87 +
1.88 + typedef FT_UInt (*CharVariantFunction)(FT_Face face,
1.89 + FT_ULong charcode,
1.90 + FT_ULong variantSelector);
1.91 + CharVariantFunction FindCharVariantFunction();
1.92 +
1.93 + nsRefPtr<gfxFT2FontBase> mGfxFont;
1.94 + FT_Face mFace;
1.95 +};
1.96 +
1.97 +#endif /* GFX_FT2UTILS_H */
