1 : /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 : * ***** BEGIN LICENSE BLOCK *****
3 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 : *
5 : * The contents of this file are subject to the Mozilla Public License Version
6 : * 1.1 (the "License"); you may not use this file except in compliance with
7 : * the License. You may obtain a copy of the License at
8 : * http://www.mozilla.org/MPL/
9 : *
10 : * Software distributed under the License is distributed on an "AS IS" basis,
11 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 : * for the specific language governing rights and limitations under the
13 : * License.
14 : *
15 : * The Original Code is Mozilla Foundation code.
16 : *
17 : * The Initial Developer of the Original Code is Mozilla Foundation.
18 : * Portions created by the Initial Developer are Copyright (C) 2009
19 : * the Initial Developer. All Rights Reserved.
20 : *
21 : * Contributor(s):
22 : * Vladimir Vukicevic <vladimir@mozilla.com>
23 : * Masayuki Nakano <masayuki@d-toybox.com>
24 : * Behdad Esfahbod <behdad@gnome.org>
25 : * Mats Palmgren <mats.palmgren@bredband.net>
26 : * Karl Tomlinson <karlt+@karlt.net>, Mozilla Corporation
27 : * Takuro Ashie <ashie@clear-code.com>
28 : *
29 : * Alternatively, the contents of this file may be used under the terms of
30 : * either the GNU General Public License Version 2 or later (the "GPL"), or
31 : * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
32 : * in which case the provisions of the GPL or the LGPL are applicable instead
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34 : * under the terms of either the GPL or the LGPL, and not to allow others to
35 : * use your version of this file under the terms of the MPL, indicate your
36 : * decision by deleting the provisions above and replace them with the notice
37 : * and other provisions required by the GPL or the LGPL. If you do not delete
38 : * the provisions above, a recipient may use your version of this file under
39 : * the terms of any one of the MPL, the GPL or the LGPL.
40 : *
41 : * ***** END LICENSE BLOCK ***** */
42 :
43 : #ifndef GFX_FT2UTILS_H
44 : #define GFX_FT2UTILS_H
45 :
46 : #include "cairo-ft.h"
47 : #include "gfxFT2FontBase.h"
48 :
49 : // Rounding and truncation functions for a FreeType fixed point number
50 : // (FT26Dot6) stored in a 32bit integer with high 26 bits for the integer
51 : // part and low 6 bits for the fractional part.
52 : #define FLOAT_FROM_26_6(x) ((x) / 64.0)
53 : #define FLOAT_FROM_16_16(x) ((x) / 65536.0)
54 : #define ROUND_26_6_TO_INT(x) ((x) >= 0 ? ((32 + (x)) >> 6) \
55 : : -((32 - (x)) >> 6))
56 :
57 : typedef struct FT_FaceRec_* FT_Face;
58 :
59 : class gfxFT2LockedFace {
60 : public:
61 0 : gfxFT2LockedFace(gfxFT2FontBase *aFont) :
62 : mGfxFont(aFont),
63 0 : mFace(cairo_ft_scaled_font_lock_face(aFont->CairoScaledFont()))
64 0 : { }
65 0 : ~gfxFT2LockedFace()
66 0 : {
67 0 : if (mFace) {
68 0 : cairo_ft_scaled_font_unlock_face(mGfxFont->CairoScaledFont());
69 : }
70 0 : }
71 :
72 0 : FT_Face get() { return mFace; };
73 :
74 : /**
75 : * Get the glyph id for a Unicode character representable by a single
76 : * glyph, or return zero if there is no such glyph. This does no caching,
77 : * so you probably want gfxFcFont::GetGlyph.
78 : */
79 : PRUint32 GetGlyph(PRUint32 aCharCode);
80 : /**
81 : * Returns 0 if there is no variation selector cmap subtable.
82 : */
83 : PRUint32 GetUVSGlyph(PRUint32 aCharCode, PRUint32 aVariantSelector);
84 :
85 : void GetMetrics(gfxFont::Metrics* aMetrics, PRUint32* aSpaceGlyph);
86 :
87 : bool GetFontTable(PRUint32 aTag, FallibleTArray<PRUint8>& aBuffer);
88 :
89 : // A scale factor for use in converting horizontal metrics from font units
90 : // to pixels.
91 0 : gfxFloat XScale()
92 : {
93 0 : if (NS_UNLIKELY(!mFace))
94 0 : return 0.0;
95 :
96 0 : const FT_Size_Metrics& ftMetrics = mFace->size->metrics;
97 :
98 0 : if (FT_IS_SCALABLE(mFace)) {
99 : // Prefer FT_Size_Metrics::x_scale to x_ppem as x_ppem does not
100 : // have subpixel accuracy.
101 : //
102 : // FT_Size_Metrics::x_scale is in 16.16 fixed point format. Its
103 : // (fractional) value is a factor that converts vertical metrics
104 : // from design units to units of 1/64 pixels, so that the result
105 : // may be interpreted as pixels in 26.6 fixed point format.
106 0 : return FLOAT_FROM_26_6(FLOAT_FROM_16_16(ftMetrics.x_scale));
107 : }
108 :
109 : // Not scalable.
110 : // FT_Size_Metrics doc says x_scale is "only relevant for scalable
111 : // font formats".
112 0 : return gfxFloat(ftMetrics.x_ppem) / gfxFloat(mFace->units_per_EM);
113 : }
114 :
115 : protected:
116 : /**
117 : * Get extents for a simple character representable by a single glyph.
118 : * The return value is the glyph id of that glyph or zero if no such glyph
119 : * exists. aExtents is only set when this returns a non-zero glyph id.
120 : */
121 : PRUint32 GetCharExtents(char aChar, cairo_text_extents_t* aExtents);
122 :
123 : typedef FT_UInt (*CharVariantFunction)(FT_Face face,
124 : FT_ULong charcode,
125 : FT_ULong variantSelector);
126 : CharVariantFunction FindCharVariantFunction();
127 :
128 : nsRefPtr<gfxFT2FontBase> mGfxFont;
129 : FT_Face mFace;
130 : };
131 :
132 : #endif /* GFX_FT2UTILS_H */
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