1/*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkDeviceProfile_DEFINED
9#define SkDeviceProfile_DEFINED
10
11#include "SkRefCnt.h"
12
13class SkDeviceProfile : public SkRefCnt {
14public:
15    enum LCDConfig {
16        kNone_LCDConfig,   // disables LCD text rendering, uses A8 instead
17        kRGB_Horizontal_LCDConfig,
18        kBGR_Horizontal_LCDConfig,
19        kRGB_Vertical_LCDConfig,
20        kBGR_Vertical_LCDConfig,
21    };
22
23    enum FontHintLevel {
24        kNone_FontHintLevel,
25        kSlight_FontHintLevel,
26        kNormal_FontHintLevel,
27        kFull_FontHintLevel,
28        kAuto_FontHintLevel,
29    };
30
31    /**
32     *  gammaExp is typically between 1.0 and 2.2. For no gamma adjustment,
33     *  specify 1.0
34     *
35     *  contrastScale will be pinned between 0.0 and 1.0. For no contrast
36     *  adjustment, specify 0.0
37     *
38     *  @param config   Describes the LCD layout for this device. If this is set
39     *                  to kNone, then all requests for LCD text will be
40     *                  devolved to A8 antialiasing.
41     *
42     *  @param level    The hinting level to be used, IF the paint specifies
43     *                  "default". Otherwise the paint's hinting level will be
44     *                  respected.
45     */
46    static SkDeviceProfile* Create(float gammaExp,
47                                   float contrastScale,
48                                   LCDConfig,
49                                   FontHintLevel);
50
51    /**
52     *  Returns the global default profile, that is used if no global profile is
53     *  specified with SetGlobal(), or if NULL is specified to SetGlobal().
54     *  The references count is *not* incremented, and the caller should not
55     *  call unref().
56     */
57    static SkDeviceProfile* GetDefault();
58
59    /**
60     *  Return the current global profile (or the default if no global had yet
61     *  been set) and increment its reference count. The call *must* call unref()
62     *  when it is done using it.
63     */
64    static SkDeviceProfile* RefGlobal();
65
66    /**
67     *  Make the specified profile be the global value for all subsequently
68     *  instantiated devices. Does not affect any existing devices.
69     *  Increments the reference count on the profile.
70     *  Specify NULL for the "identity" profile (where there is no gamma or
71     *  contrast correction).
72     */
73    static void SetGlobal(SkDeviceProfile*);
74
75    float getFontGammaExponent() const { return fGammaExponent; }
76    float getFontContrastScale() const { return fContrastScale; }
77
78    /**
79     *  Given a luminance byte (0 for black, 0xFF for white), generate a table
80     *  that applies the gamma/contrast settings to linear coverage values.
81     */
82    void generateTableForLuminanceByte(U8CPU lumByte, uint8_t table[256]) const;
83
84private:
85    SkDeviceProfile(float gammaExp, float contrastScale, LCDConfig,
86                    FontHintLevel);
87
88    float           fGammaExponent;
89    float           fContrastScale;
90    LCDConfig       fLCDConfig;
91    FontHintLevel   fFontHintLevel;
92};
93
94#endif
95
96