SkBlitRow.h revision f0f4e9abba62a405b7a41e40fcee20b45eb348ee 
1#ifndef SkBlitRow_DEFINED
2#define SkBlitRow_DEFINED
3
4#include "SkBitmap.h"
5#include "SkColor.h"
6
7class SkBlitRow {
8public:
9    enum Flags16 {
10        //! If set, the alpha parameter will be != 255
11        kGlobalAlpha_Flag   = 0x01,
12        //! If set, the src colors may have alpha != 255
13        kSrcPixelAlpha_Flag = 0x02,
14        //! If set, the resulting 16bit colors should be dithered
15        kDither_Flag        = 0x04
16    };
17
18    /** Function pointer that reads a scanline of src SkPMColors, and writes
19        a corresponding scanline of 16bit colors (specific format based on the
20        config passed to the Factory.
21
22        The x,y params are useful just for dithering
23
24        @param alpha A global alpha to be applied to all of the src colors
25        @param x The x coordinate of the beginning of the scanline
26        @param y THe y coordinate of the scanline
27     */
28    typedef void (*Proc)(uint16_t* SK_RESTRICT dst,
29                         const SkPMColor* SK_RESTRICT src,
30                         int count, U8CPU alpha, int x, int y);
31
32    //! Public entry-point to return a blit function ptr
33    static Proc Factory(unsigned flags, SkBitmap::Config);
34
35    ///////////// D32 version
36
37    enum Flags32 {
38        kGlobalAlpha_Flag32     = 1 << 0,
39        kSrcPixelAlpha_Flag32   = 1 << 1,
40    };
41
42    /** Function pointer that blends 32bit colors onto a 32bit destination.
43        @param dst  array of dst 32bit colors
44        @param src  array of src 32bit colors (w/ or w/o alpha)
45        @param count number of colors to blend
46        @param alpha global alpha to be applied to all src colors
47     */
48    typedef void (*Proc32)(uint32_t* SK_RESTRICT dst,
49                         const SkPMColor* SK_RESTRICT src,
50                         int count, U8CPU alpha);
51
52    static Proc32 Factory32(unsigned flags32);
53
54    /** Blend a single color onto a row of S32 pixels, writing the result
55        into a row of D32 pixels. src and dst may be the same memory, but
56        if they are not, they may not overlap.
57     */
58    static void Color32(SkPMColor dst[], const SkPMColor src[], int count,
59                         SkPMColor color);
60
61    /** Blend a single color onto a row of 32bit pixels, writing the result
62        into the same row.
63     */
64    static void Color32(SkPMColor row[], int count, SkPMColor color) {
65        Color32(row, row, count, color);
66    }
67
68    /** These static functions are called by the Factory and Factory32
69        functions, and should return either NULL, or a
70        platform-specific function-ptr to be used in place of the
71        system default.
72     */
73
74    static Proc32 PlatformProcs32(unsigned flags);
75    static Proc PlatformProcs565(unsigned flags);
76    static Proc PlatformProcs4444(unsigned flags);
77
78private:
79    enum {
80        kFlags16_Mask = 7,
81        kFlags32_Mask = 3
82    };
83};
84
85#endif
86