SkDeviceProperties.h revision ba3284e7bbb830749206414890f8152e421969f2 
1#ifndef SkDeviceProperties_DEFINED
2#define SkDeviceProperties_DEFINED
3
4#ifndef SK_GAMMA_EXPONENT
5    #define SK_GAMMA_EXPONENT (2.2f)
6#endif
7
8#ifdef SK_GAMMA_SRGB
9    #undef SK_GAMMA_EXPONENT
10    #define SK_GAMMA_EXPONENT (0.0f)
11#endif
12
13//TODO: get everyone to stop using SkFontHost::SetSubpixel* and remove this import.
14#include "SkFontHost.h"
15
16struct SkDeviceProperties {
17    struct Geometry {
18        /** The orientation of the pixel specifies the interpretation of the
19        *  layout. If the orientation is horizontal, the layout is interpreted as
20        *  left to right. It the orientation is vertical, the layout is
21        *  interpreted top to bottom (rotated 90deg cw from horizontal).
22        */
23        enum Orientation {
24            kUnknown_Orientation      = 0x0,
25            kKnown_Orientation        = 0x2,
26
27            kHorizontal_Orientation   = 0x2,  //!< this is the default
28            kVertical_Orientation     = 0x3,
29
30            kOrientationMask          = 0x3,
31        };
32
33        /** The layout of the pixel specifies its subpixel geometry.
34        *
35        *  kUnknown_Layout means that the subpixel elements are not spatially
36        *  separated in any known or usable fashion.
37        */
38        enum Layout {
39            kUnknown_Layout   = 0x0,
40            kKnown_Layout     = 0x8,
41
42            kRGB_Layout       = 0x8,  //!< this is the default
43            kBGR_Layout       = 0xC,
44
45            kLayoutMask       = 0xC,
46        };
47
48        Orientation getOrientation() {
49            return static_cast<Orientation>(fGeometry | kOrientationMask);
50        }
51        Layout getLayout() {
52            return static_cast<Layout>(fGeometry | kLayoutMask);
53        }
54
55        bool isOrientationKnown() {
56            return SkToBool(fGeometry & kKnown_Orientation);
57        }
58        bool isLayoutKnown() {
59            return SkToBool(fGeometry & kKnown_Layout);
60        }
61
62    private:
63        //TODO: get everyone to stop using SkFontHost::SetSubpixel* and replace these calls with constants.
64        static Orientation fromOldOrientation(SkFontHost::LCDOrientation orientation) {
65            switch (orientation) {
66            case SkFontHost::kHorizontal_LCDOrientation: return kHorizontal_Orientation;
67            case SkFontHost::kVertical_LCDOrientation: return kVertical_Orientation;
68            default: return kUnknown_Orientation;
69            }
70        }
71        static Layout fromOldLayout(SkFontHost::LCDOrder order) {
72            switch (order) {
73            case SkFontHost::kRGB_LCDOrder: return kRGB_Layout;
74            case SkFontHost::kBGR_LCDOrder: return kBGR_Layout;
75            default: return kUnknown_Layout;
76            }
77        }
78    public:
79        static Geometry MakeDefault() {
80            Orientation orientation = fromOldOrientation(SkFontHost::GetSubpixelOrientation()); //kHorizontal_Orientation
81            Layout layout = fromOldLayout(SkFontHost::GetSubpixelOrder()); //kRGB_Layout
82            Geometry ret = { orientation | layout };
83            return ret;
84        }
85
86        static Geometry Make(Orientation orientation, Layout layout) {
87            Geometry ret = { orientation | layout };
88            return ret;
89        }
90
91        uint8_t fGeometry;
92    };
93
94    static SkDeviceProperties MakeDefault() {
95        SkDeviceProperties ret = { Geometry::MakeDefault(), SK_GAMMA_EXPONENT };
96        return ret;
97    }
98
99    static SkDeviceProperties Make(Geometry geometry, SkScalar gamma) {
100        SkDeviceProperties ret = { geometry, gamma };
101        return ret;
102    }
103
104    /** Each pixel of an image will have some number of channels.
105     *  Can the layout of those channels be exploited? */
106    Geometry fGeometry;
107
108    /** Represents the color space of the image. This is a woefully inadequate beginning. */
109    SkScalar fGamma;
110};
111
112#endif
113