gecko-dev/gfx/thebes/gfxHarfBuzzShaper.h

127 lines
5.2 KiB
C++

/* -*- 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 thebes gfx code.
*
* The Initial Developer of the Original Code is Mozilla Corporation.
* Portions created by the Initial Developer are Copyright (C) 2009-2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Jonathan Kew <jfkthame@gmail.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_HARFBUZZSHAPER_H
#define GFX_HARFBUZZSHAPER_H
#include "gfxTypes.h"
#include "gfxFont.h"
#include "nsDataHashtable.h"
#include "nsPoint.h"
#include "harfbuzz/hb.h"
class gfxHarfBuzzShaper : public gfxFontShaper {
public:
gfxHarfBuzzShaper(gfxFont *aFont);
virtual ~gfxHarfBuzzShaper();
virtual PRBool InitTextRun(gfxContext *aContext,
gfxTextRun *aTextRun,
const PRUnichar *aString,
PRUint32 aRunStart,
PRUint32 aRunLength,
PRInt32 aRunScript);
// get a given font table in harfbuzz blob form
hb_blob_t * GetFontTable(hb_tag_t aTag) const;
// map unicode character to glyph ID
hb_codepoint_t GetGlyph(hb_codepoint_t unicode,
hb_codepoint_t variation_selector) const;
// get harfbuzz glyph advance, in font design units
void GetGlyphAdvance(gfxContext *aContext,
hb_codepoint_t glyph,
hb_position_t *x_advance,
hb_position_t *y_advance) const;
hb_position_t GetKerning(PRUint16 aFirstGlyph,
PRUint16 aSecondGlyph) const;
protected:
// extract glyphs from HarfBuzz buffer and store into the gfxTextRun
nsresult SetGlyphsFromRun(gfxContext *aContext,
gfxTextRun *aTextRun,
hb_buffer_t *aBuffer,
PRUint32 aTextRunOffset,
PRUint32 aRunLength);
// retrieve glyph positions, applying advance adjustments and attachments
// returns results in appUnits
nscoord GetGlyphPositions(gfxContext *aContext,
hb_buffer_t *aBuffer,
nsTArray<nsPoint>& aPositions,
PRUint32 aAppUnitsPerDevUnit);
// harfbuzz face object, created on first use (caches font tables)
hb_face_t *mHBFace;
// Following table references etc are declared "mutable" because the
// harfbuzz callback functions take a const ptr to the shaper, but
// wish to cache tables here to avoid repeatedly looking them up
// in the font.
// Old-style TrueType kern table, if we're not doing GPOS kerning
mutable hb_blob_t *mKernTable;
// Cached copy of the hmtx table and numLongMetrics field from hhea,
// for use when looking up glyph metrics; initialized to 0 by the
// constructor so we can tell it hasn't been set yet.
// This is a signed value so that we can use -1 to indicate
// an error (if the hhea table was not available).
mutable hb_blob_t *mHmtxTable;
mutable PRInt32 mNumLongMetrics;
// Cached pointer to cmap subtable to be used for char-to-glyph mapping.
// This comes from GetFontTablePtr; if it is non-null, our destructor
// must call ReleaseFontTablePtr to avoid permanently caching the table.
mutable hb_blob_t *mCmapTable;
mutable PRInt32 mCmapFormat;
mutable PRUint32 mSubtableOffset;
mutable PRUint32 mUVSTableOffset;
// Whether the font implements GetGlyph, or we should read tables
// directly
PRPackedBool mUseFontGetGlyph;
// Whether the font implements GetGlyphWidth, or we should read tables
// directly to get ideal widths
PRPackedBool mUseFontGlyphWidths;
};
#endif /* GFX_HARFBUZZSHAPER_H */