Add skia to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@16 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 189 insertions, 0 deletions

diff --git a/skia/include/SkDither.h b/skia/include/SkDither.h
new file mode 100644
index 0000000..d486437
--- /dev/null
+++ b/skia/include/SkDither.h
@@ -0,0 +1,189 @@
+#ifndef SkDither_DEFINED
+#define SkDither_DEFINED
+
+#include "SkColorPriv.h"
+
+#define SK_DitherValueMax4444   15
+#define SK_DitherValueMax565    7
+
+/*  need to use macros for bit-counts for each component, and then
+    move these into SkColorPriv.h
+*/
+
+#define SkDITHER_R32_FOR_565_MACRO(r, d)    (r + d - (r >> 5))
+#define SkDITHER_G32_FOR_565_MACRO(g, d)    (g + (d >> 1) - (g >> 6))
+#define SkDITHER_B32_FOR_565_MACRO(b, d)    (b + d - (b >> 5))
+
+#define SkDITHER_A32_FOR_4444_MACRO(a, d)    (a + 15 - (a >> 4))
+#define SkDITHER_R32_FOR_4444_MACRO(r, d)    (r + d - (r >> 4))
+#define SkDITHER_G32_FOR_4444_MACRO(g, d)    (g + d - (g >> 4))
+#define SkDITHER_B32_FOR_4444_MACRO(b, d)    (b + d - (b >> 4))
+
+#ifdef SK_DEBUG
+    inline unsigned SkDITHER_R32_FOR_565(unsigned r, unsigned d)
+    {
+        SkASSERT(d <= SK_DitherValueMax565);
+        SkA32Assert(r);
+        r = SkDITHER_R32_FOR_565_MACRO(r, d);
+        SkA32Assert(r);
+        return r;
+    }
+    inline unsigned SkDITHER_G32_FOR_565(unsigned g, unsigned d)
+    {
+        SkASSERT(d <= SK_DitherValueMax565);
+        SkG32Assert(g);
+        g = SkDITHER_G32_FOR_565_MACRO(g, d);
+        SkG32Assert(g);
+        return g;
+    }
+    inline unsigned SkDITHER_B32_FOR_565(unsigned b, unsigned d)
+    {
+        SkASSERT(d <= SK_DitherValueMax565);
+        SkB32Assert(b);
+        b = SkDITHER_B32_FOR_565_MACRO(b, d);
+        SkB32Assert(b);
+        return b;
+    }
+#else
+    #define SkDITHER_R32_FOR_565(r, d)  SkDITHER_R32_FOR_565_MACRO(r, d)
+    #define SkDITHER_G32_FOR_565(g, d)  SkDITHER_G32_FOR_565_MACRO(g, d)
+    #define SkDITHER_B32_FOR_565(b, d)  SkDITHER_B32_FOR_565_MACRO(b, d)
+#endif
+
+#define SkDITHER_R32To565(r, d)  SkR32ToR16(SkDITHER_R32_FOR_565(r, d))
+#define SkDITHER_G32To565(g, d)  SkG32ToG16(SkDITHER_G32_FOR_565(g, d))
+#define SkDITHER_B32To565(b, d)  SkB32ToB16(SkDITHER_B32_FOR_565(b, d))
+
+#define SkDITHER_A32To4444(a, d)  SkA32To4444(SkDITHER_A32_FOR_4444_MACRO(a, d))
+#define SkDITHER_R32To4444(r, d)  SkR32To4444(SkDITHER_R32_FOR_4444_MACRO(r, d))
+#define SkDITHER_G32To4444(g, d)  SkG32To4444(SkDITHER_G32_FOR_4444_MACRO(g, d))
+#define SkDITHER_B32To4444(b, d)  SkB32To4444(SkDITHER_B32_FOR_4444_MACRO(b, d))
+
+static inline SkPMColor SkDitherARGB32For565(SkPMColor c, unsigned dither)
+{
+    SkASSERT(dither <= SK_DitherValueMax565);
+    
+    unsigned sa = SkGetPackedA32(c);
+    dither = SkAlphaMul(dither, SkAlpha255To256(sa));
+
+    unsigned sr = SkGetPackedR32(c);
+    unsigned sg = SkGetPackedG32(c);
+    unsigned sb = SkGetPackedB32(c);
+    sr = SkDITHER_R32_FOR_565(sr, dither);
+    sg = SkDITHER_G32_FOR_565(sg, dither);
+    sb = SkDITHER_B32_FOR_565(sb, dither);
+    
+    return SkPackARGB32(sa, sr, sg, sb);
+}
+
+static inline SkPMColor SkDitherRGB32For565(SkPMColor c, unsigned dither)
+{
+    SkASSERT(dither <= SK_DitherValueMax565);
+    
+    unsigned sr = SkGetPackedR32(c);
+    unsigned sg = SkGetPackedG32(c);
+    unsigned sb = SkGetPackedB32(c);
+    sr = SkDITHER_R32_FOR_565(sr, dither);
+    sg = SkDITHER_G32_FOR_565(sg, dither);
+    sb = SkDITHER_B32_FOR_565(sb, dither);
+    
+    return SkPackARGB32(0xFF, sr, sg, sb);
+}
+
+static inline uint16_t SkDitherRGBTo565(U8CPU r, U8CPU g, U8CPU b,
+                                              unsigned dither)
+{
+    SkASSERT(dither <= SK_DitherValueMax565);
+    r = SkDITHER_R32To565(r, dither);
+    g = SkDITHER_G32To565(g, dither);
+    b = SkDITHER_B32To565(b, dither);
+    return SkPackRGB16(r, g, b);
+}
+
+static inline uint16_t SkDitherRGB32To565(SkPMColor c, unsigned dither)
+{
+    SkASSERT(dither <= SK_DitherValueMax565);
+    
+    unsigned sr = SkGetPackedR32(c);
+    unsigned sg = SkGetPackedG32(c);
+    unsigned sb = SkGetPackedB32(c);
+    sr = SkDITHER_R32To565(sr, dither);
+    sg = SkDITHER_G32To565(sg, dither);
+    sb = SkDITHER_B32To565(sb, dither);
+    
+    return SkPackRGB16(sr, sg, sb);
+}
+
+static inline uint16_t SkDitherARGB32To565(U8CPU sa, SkPMColor c, unsigned dither)
+{
+    SkASSERT(dither <= SK_DitherValueMax565);    
+    dither = SkAlphaMul(dither, SkAlpha255To256(sa));
+    
+    unsigned sr = SkGetPackedR32(c);
+    unsigned sg = SkGetPackedG32(c);
+    unsigned sb = SkGetPackedB32(c);
+    sr = SkDITHER_R32To565(sr, dither);
+    sg = SkDITHER_G32To565(sg, dither);
+    sb = SkDITHER_B32To565(sb, dither);
+    
+    return SkPackRGB16(sr, sg, sb);
+}
+
+///////////////////////// 4444
+
+static inline SkPMColor16 SkDitherARGB32To4444(U8CPU a, U8CPU r, U8CPU g,
+                                               U8CPU b, unsigned dither)
+{
+    dither = SkAlphaMul(dither, SkAlpha255To256(a));
+
+    a = SkDITHER_A32To4444(a, dither);
+    r = SkDITHER_R32To4444(r, dither);
+    g = SkDITHER_G32To4444(g, dither);
+    b = SkDITHER_B32To4444(b, dither);
+    
+    return SkPackARGB4444(a, r, g, b);
+}
+
+static inline SkPMColor16 SkDitherARGB32To4444(SkPMColor c, unsigned dither)
+{
+    unsigned a = SkGetPackedA32(c);
+    unsigned r = SkGetPackedR32(c);
+    unsigned g = SkGetPackedG32(c);
+    unsigned b = SkGetPackedB32(c);
+
+    dither = SkAlphaMul(dither, SkAlpha255To256(a));
+
+    a = SkDITHER_A32To4444(a, dither);
+    r = SkDITHER_R32To4444(r, dither);
+    g = SkDITHER_G32To4444(g, dither);
+    b = SkDITHER_B32To4444(b, dither);
+    
+    return SkPackARGB4444(a, r, g, b);
+}
+
+// TODO: need dither routines for 565 -> 4444
+
+// this toggles between a 4x4 and a 1x4 array
+//#define ENABLE_DITHER_MATRIX_4X4
+
+#ifdef ENABLE_DITHER_MATRIX_4X4
+    extern const uint8_t gDitherMatrix_4Bit_4X4[4][4];
+    extern const uint8_t gDitherMatrix_3Bit_4X4[4][4];
+
+    #define DITHER_4444_SCAN(y) const uint8_t* dither_scan = gDitherMatrix_4Bit_4X4[(y) & 3]
+    #define DITHER_565_SCAN(y)  const uint8_t* dither_scan = gDitherMatrix_3Bit_4X4[(y) & 3]
+
+    #define DITHER_VALUE(x) dither_scan[(x) & 3]
+#else
+    extern const uint16_t gDitherMatrix_4Bit_16[4];
+    extern const uint16_t gDitherMatrix_3Bit_16[4];
+
+    #define DITHER_4444_SCAN(y) const uint16_t dither_scan = gDitherMatrix_4Bit_16[(y) & 3]
+    #define DITHER_565_SCAN(y)  const uint16_t dither_scan = gDitherMatrix_3Bit_16[(y) & 3]
+
+    #define DITHER_VALUE(x) ((dither_scan >> (((x) & 3) << 2)) & 0xF)
+#endif
+
+#define DITHER_INC_X(x) ++(x)
+
+#endif