| /* |
| * 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/core/SkMath.h" |
| #include "include/private/SkTPin.h" |
| #include "include/private/base/SkTo.h" |
| |
| /** 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) { |
| return src + SkAlphaMulQ(dst, SkAlpha255To256(255 - SkGetPackedA32(src))); |
| } |
| |
| #endif |