1 files changed, 167 insertions, 0 deletions
diff --git a/gfx/skia/skia/include/core/SkColorPriv.h b/gfx/skia/skia/include/core/SkColorPriv.h
new file mode 100644
index 0000000000..f89de9db72
--- /dev/null
+++ b/gfx/skia/skia/include/core/SkColorPriv.h
@@ -0,0 +1,167 @@
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkColorPriv_DEFINED
+#define SkColorPriv_DEFINED
+
+#include "include/core/SkColor.h"
+#include "include/private/base/SkMath.h"
+#include "include/private/base/SkTPin.h"
+#include "include/private/base/SkTo.h"
+
+#include <algorithm>
+
+/** Turn 0..255 into 0..256 by adding 1 at the half-way point. Used to turn a
+    byte into a scale value, so that we can say scale * value >> 8 instead of
+    alpha * value / 255.
+
+    In debugging, asserts that alpha is 0..255
+*/
+static inline unsigned SkAlpha255To256(U8CPU alpha) {
+    SkASSERT(SkToU8(alpha) == alpha);
+    // this one assues that blending on top of an opaque dst keeps it that way
+    // even though it is less accurate than a+(a>>7) for non-opaque dsts
+    return alpha + 1;
+}
+
+/** Multiplify value by 0..256, and shift the result down 8
+    (i.e. return (value * alpha256) >> 8)
+ */
+#define SkAlphaMul(value, alpha256)     (((value) * (alpha256)) >> 8)
+
+static inline U8CPU SkUnitScalarClampToByte(SkScalar x) {
+    return static_cast<U8CPU>(SkTPin(x, 0.0f, 1.0f) * 255 + 0.5);
+}
+
+#define SK_A32_BITS     8
+#define SK_R32_BITS     8
+#define SK_G32_BITS     8
+#define SK_B32_BITS     8
+
+#define SK_A32_MASK     ((1 << SK_A32_BITS) - 1)
+#define SK_R32_MASK     ((1 << SK_R32_BITS) - 1)
+#define SK_G32_MASK     ((1 << SK_G32_BITS) - 1)
+#define SK_B32_MASK     ((1 << SK_B32_BITS) - 1)
+
+/*
+ *  Skia's 32bit backend only supports 1 swizzle order at a time (compile-time).
+ *  This is specified by SK_R32_SHIFT=0 or SK_R32_SHIFT=16.
+ *
+ *  For easier compatibility with Skia's GPU backend, we further restrict these
+ *  to either (in memory-byte-order) RGBA or BGRA. Note that this "order" does
+ *  not directly correspond to the same shift-order, since we have to take endianess
+ *  into account.
+ *
+ *  Here we enforce this constraint.
+ */
+
+#define SK_RGBA_R32_SHIFT   0
+#define SK_RGBA_G32_SHIFT   8
+#define SK_RGBA_B32_SHIFT   16
+#define SK_RGBA_A32_SHIFT   24
+
+#define SK_BGRA_B32_SHIFT   0
+#define SK_BGRA_G32_SHIFT   8
+#define SK_BGRA_R32_SHIFT   16
+#define SK_BGRA_A32_SHIFT   24
+
+#if defined(SK_PMCOLOR_IS_RGBA) || defined(SK_PMCOLOR_IS_BGRA)
+    #error "Configure PMCOLOR by setting SK_R32_SHIFT."
+#endif
+
+// Deduce which SK_PMCOLOR_IS_ to define from the _SHIFT defines
+
+#if (SK_A32_SHIFT == SK_RGBA_A32_SHIFT && \
+     SK_R32_SHIFT == SK_RGBA_R32_SHIFT && \
+     SK_G32_SHIFT == SK_RGBA_G32_SHIFT && \
+     SK_B32_SHIFT == SK_RGBA_B32_SHIFT)
+    #define SK_PMCOLOR_IS_RGBA
+#elif (SK_A32_SHIFT == SK_BGRA_A32_SHIFT && \
+       SK_R32_SHIFT == SK_BGRA_R32_SHIFT && \
+       SK_G32_SHIFT == SK_BGRA_G32_SHIFT && \
+       SK_B32_SHIFT == SK_BGRA_B32_SHIFT)
+    #define SK_PMCOLOR_IS_BGRA
+#else
+    #error "need 32bit packing to be either RGBA or BGRA"
+#endif
+
+#define SkGetPackedA32(packed)      ((uint32_t)((packed) << (24 - SK_A32_SHIFT)) >> 24)
+#define SkGetPackedR32(packed)      ((uint32_t)((packed) << (24 - SK_R32_SHIFT)) >> 24)
+#define SkGetPackedG32(packed)      ((uint32_t)((packed) << (24 - SK_G32_SHIFT)) >> 24)
+#define SkGetPackedB32(packed)      ((uint32_t)((packed) << (24 - SK_B32_SHIFT)) >> 24)
+
+#define SkA32Assert(a)  SkASSERT((unsigned)(a) <= SK_A32_MASK)
+#define SkR32Assert(r)  SkASSERT((unsigned)(r) <= SK_R32_MASK)
+#define SkG32Assert(g)  SkASSERT((unsigned)(g) <= SK_G32_MASK)
+#define SkB32Assert(b)  SkASSERT((unsigned)(b) <= SK_B32_MASK)
+
+/**
+ *  Pack the components into a SkPMColor, checking (in the debug version) that
+ *  the components are 0..255, and are already premultiplied (i.e. alpha >= color)
+ */
+static inline SkPMColor SkPackARGB32(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
+    SkA32Assert(a);
+    SkASSERT(r <= a);
+    SkASSERT(g <= a);
+    SkASSERT(b <= a);
+
+    return (a << SK_A32_SHIFT) | (r << SK_R32_SHIFT) |
+           (g << SK_G32_SHIFT) | (b << SK_B32_SHIFT);
+}
+
+/**
+ *  Same as SkPackARGB32, but this version guarantees to not check that the
+ *  values are premultiplied in the debug version.
+ */
+static inline SkPMColor SkPackARGB32NoCheck(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
+    return (a << SK_A32_SHIFT) | (r << SK_R32_SHIFT) |
+           (g << SK_G32_SHIFT) | (b << SK_B32_SHIFT);
+}
+
+static inline
+SkPMColor SkPremultiplyARGBInline(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
+    SkA32Assert(a);
+    SkR32Assert(r);
+    SkG32Assert(g);
+    SkB32Assert(b);
+
+    if (a != 255) {
+        r = SkMulDiv255Round(r, a);
+        g = SkMulDiv255Round(g, a);
+        b = SkMulDiv255Round(b, a);
+    }
+    return SkPackARGB32(a, r, g, b);
+}
+
+// When Android is compiled optimizing for size, SkAlphaMulQ doesn't get
+// inlined; forcing inlining significantly improves performance.
+static SK_ALWAYS_INLINE uint32_t SkAlphaMulQ(uint32_t c, unsigned scale) {
+    uint32_t mask = 0xFF00FF;
+
+    uint32_t rb = ((c & mask) * scale) >> 8;
+    uint32_t ag = ((c >> 8) & mask) * scale;
+    return (rb & mask) | (ag & ~mask);
+}
+
+static inline SkPMColor SkPMSrcOver(SkPMColor src, SkPMColor dst) {
+    uint32_t scale = SkAlpha255To256(255 - SkGetPackedA32(src));
+
+    uint32_t mask = 0xFF00FF;
+    uint32_t rb = (((dst & mask) * scale) >> 8) & mask;
+    uint32_t ag = (((dst >> 8) & mask) * scale) & ~mask;
+
+    rb += (src &  mask);
+    ag += (src & ~mask);
+
+    // Color channels (but not alpha) can overflow, so we have to saturate to 0xFF in each lane.
+    return std::min(rb & 0x000001FF, 0x000000FFU) |
+           std::min(ag & 0x0001FF00, 0x0000FF00U) |
+           std::min(rb & 0x01FF0000, 0x00FF0000U) |
+                   (ag & 0xFF000000);
+}
+
+#endif