gecko/gfx/thebes/gfxFT2Utils.h

133 lines
5.1 KiB
C
Raw Normal View History

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Foundation code.
*
* The Initial Developer of the Original Code is Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Vladimir Vukicevic <vladimir@mozilla.com>
* Masayuki Nakano <masayuki@d-toybox.com>
* Behdad Esfahbod <behdad@gnome.org>
* Mats Palmgren <mats.palmgren@bredband.net>
* Karl Tomlinson <karlt+@karlt.net>, Mozilla Corporation
* Takuro Ashie <ashie@clear-code.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef GFX_FT2UTILS_H
#define GFX_FT2UTILS_H
#include "cairo-ft.h"
#include "gfxFT2FontBase.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:
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.
*/
PRUint32 GetGlyph(PRUint32 aCharCode);
/**
* Returns 0 if there is no variation selector cmap subtable.
*/
PRUint32 GetUVSGlyph(PRUint32 aCharCode, PRUint32 aVariantSelector);
void GetMetrics(gfxFont::Metrics* aMetrics, PRUint32* aSpaceGlyph);
PRBool GetFontTable(PRUint32 aTag, FallibleTArray<PRUint8>& aBuffer);
// A scale factor for use in converting horizontal metrics from font units
// to pixels.
gfxFloat XScale()
{
if (NS_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.
*/
PRUint32 GetCharExtents(char aChar, cairo_text_extents_t* aExtents);
typedef FT_UInt (*CharVariantFunction)(FT_Face face,
FT_ULong charcode,
FT_ULong variantSelector);
CharVariantFunction FindCharVariantFunction();
nsRefPtr<gfxFT2FontBase> mGfxFont;
FT_Face mFace;
};
#endif /* GFX_FT2UTILS_H */