/*
* Copyright 2010 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrColor_DEFINED
#define GrColor_DEFINED
#include "GrTypes.h"
#include "SkColor.h"
#include "SkColorPriv.h"
#include "SkUnPreMultiply.h"
/**
* GrColor is 4 bytes for R, G, B, A, in a specific order defined below. The components are stored
* premultiplied.
*/
typedef uint32_t GrColor;
// shift amount to assign a component to a GrColor int
// These shift values are chosen for compatibility with GL attrib arrays
// ES doesn't allow BGRA vertex attrib order so if they were not in this order
// we'd have to swizzle in shaders.
#ifdef SK_CPU_BENDIAN
#define GrColor_SHIFT_R 24
#define GrColor_SHIFT_G 16
#define GrColor_SHIFT_B 8
#define GrColor_SHIFT_A 0
#else
#define GrColor_SHIFT_R 0
#define GrColor_SHIFT_G 8
#define GrColor_SHIFT_B 16
#define GrColor_SHIFT_A 24
#endif
/**
* Pack 4 components (RGBA) into a GrColor int
*/
static inline GrColor GrColorPackRGBA(unsigned r, unsigned g, unsigned b, unsigned a) {
SkASSERT((uint8_t)r == r);
SkASSERT((uint8_t)g == g);
SkASSERT((uint8_t)b == b);
SkASSERT((uint8_t)a == a);
return (r << GrColor_SHIFT_R) |
(g << GrColor_SHIFT_G) |
(b << GrColor_SHIFT_B) |
(a << GrColor_SHIFT_A);
}
/**
* Packs a color with an alpha channel replicated across all four channels.
*/
static inline GrColor GrColorPackA4(unsigned a) {
SkASSERT((uint8_t)a == a);
return (a << GrColor_SHIFT_R) |
(a << GrColor_SHIFT_G) |
(a << GrColor_SHIFT_B) |
(a << GrColor_SHIFT_A);
}
// extract a component (byte) from a GrColor int
#define GrColorUnpackR(color) (((color) >> GrColor_SHIFT_R) & 0xFF)
#define GrColorUnpackG(color) (((color) >> GrColor_SHIFT_G) & 0xFF)
#define GrColorUnpackB(color) (((color) >> GrColor_SHIFT_B) & 0xFF)
#define GrColorUnpackA(color) (((color) >> GrColor_SHIFT_A) & 0xFF)
/**
* Since premultiplied means that alpha >= color, we construct a color with
* each component==255 and alpha == 0 to be "illegal"
*/
#define GrColor_ILLEGAL (~(0xFF << GrColor_SHIFT_A))
#define GrColor_WHITE 0xFFFFFFFF
#define GrColor_TRANS_BLACK 0x0
/**
* Assert in debug builds that a GrColor is premultiplied.
*/
static inline void GrColorIsPMAssert(GrColor SkDEBUGCODE(c)) {
#ifdef SK_DEBUG
unsigned a = GrColorUnpackA(c);
unsigned r = GrColorUnpackR(c);
unsigned g = GrColorUnpackG(c);
unsigned b = GrColorUnpackB(c);
SkASSERT(r <= a);
SkASSERT(g <= a);
SkASSERT(b <= a);
#endif
}
/** Converts a GrColor to an rgba array of GrGLfloat */
static inline void GrColorToRGBAFloat(GrColor color, float rgba[4]) {
static const float ONE_OVER_255 = 1.f / 255.f;
rgba[0] = GrColorUnpackR(color) * ONE_OVER_255;
rgba[1] = GrColorUnpackG(color) * ONE_OVER_255;
rgba[2] = GrColorUnpackB(color) * ONE_OVER_255;
rgba[3] = GrColorUnpackA(color) * ONE_OVER_255;
}
/** Normalizes and coverts an uint8_t to a float. [0, 255] -> [0.0, 1.0] */
static inline float GrNormalizeByteToFloat(uint8_t value) {
static const float ONE_OVER_255 = 1.f / 255.f;
return value * ONE_OVER_255;
}
/** Determines whether the color is opaque or not. */
static inline bool GrColorIsOpaque(GrColor color) {
return (color & (0xFFU << GrColor_SHIFT_A)) == (0xFFU << GrColor_SHIFT_A);
}
/** Returns an unpremuled version of the GrColor. */
static inline GrColor GrUnPreMulColor(GrColor color) {
unsigned r = GrColorUnpackR(color);
unsigned g = GrColorUnpackG(color);
unsigned b = GrColorUnpackB(color);
unsigned a = GrColorUnpackA(color);
SkPMColor colorPM = SkPackARGB32(a, r, g, b);
SkColor colorUPM = SkUnPreMultiply::PMColorToColor(colorPM);
r = SkColorGetR(colorUPM);
g = SkColorGetG(colorUPM);
b = SkColorGetB(colorUPM);
a = SkColorGetA(colorUPM);
return GrColorPackRGBA(r, g, b, a);
}
/**
* Flags used for bitfields of color components. They are defined so that the bit order reflects the
* GrColor shift order.
*/
enum GrColorComponentFlags {
kR_GrColorComponentFlag = 1 << (GrColor_SHIFT_R / 8),
kG_GrColorComponentFlag = 1 << (GrColor_SHIFT_G / 8),
kB_GrColorComponentFlag = 1 << (GrColor_SHIFT_B / 8),
kA_GrColorComponentFlag = 1 << (GrColor_SHIFT_A / 8),
kRGB_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag |
kB_GrColorComponentFlag),
kRGBA_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag |
kB_GrColorComponentFlag | kA_GrColorComponentFlag)
};
static inline char GrColorComponentFlagToChar(GrColorComponentFlags component) {
SkASSERT(SkIsPow2(component));
switch (component) {
case kR_GrColorComponentFlag:
return 'r';
case kG_GrColorComponentFlag:
return 'g';
case kB_GrColorComponentFlag:
return 'b';
case kA_GrColorComponentFlag:
return 'a';
default:
SkFAIL("Invalid color component flag.");
return '\0';
}
}
static inline uint32_t GrPixelConfigComponentMask(GrPixelConfig config) {
SkASSERT(config >= 0 && config < kGrPixelConfigCnt);
static const uint32_t kFlags[] = {
0, // kUnknown_GrPixelConfig
kA_GrColorComponentFlag, // kAlpha_8_GrPixelConfig
kRGBA_GrColorComponentFlags, // kIndex_8_GrPixelConfig
kRGB_GrColorComponentFlags, // kRGB_565_GrPixelConfig
kRGBA_GrColorComponentFlags, // kRGBA_4444_GrPixelConfig
kRGBA_GrColorComponentFlags, // kRGBA_8888_GrPixelConfig
kRGBA_GrColorComponentFlags, // kBGRA_8888_GrPixelConfig
kRGBA_GrColorComponentFlags, // kSRGBA_8888_GrPixelConfig
kRGB_GrColorComponentFlags, // kETC1_GrPixelConfig
kA_GrColorComponentFlag, // kLATC_GrPixelConfig
kA_GrColorComponentFlag, // kR11_EAC_GrPixelConfig
kRGBA_GrColorComponentFlags, // kASTC_12x12_GrPixelConfig
kRGBA_GrColorComponentFlags, // kRGBA_float_GrPixelConfig
kA_GrColorComponentFlag, // kAlpha_16_GrPixelConfig
};
return kFlags[config];
GR_STATIC_ASSERT(0 == kUnknown_GrPixelConfig);
GR_STATIC_ASSERT(1 == kAlpha_8_GrPixelConfig);
GR_STATIC_ASSERT(2 == kIndex_8_GrPixelConfig);
GR_STATIC_ASSERT(3 == kRGB_565_GrPixelConfig);
GR_STATIC_ASSERT(4 == kRGBA_4444_GrPixelConfig);
GR_STATIC_ASSERT(5 == kRGBA_8888_GrPixelConfig);
GR_STATIC_ASSERT(6 == kBGRA_8888_GrPixelConfig);
GR_STATIC_ASSERT(7 == kSRGBA_8888_GrPixelConfig);
GR_STATIC_ASSERT(8 == kETC1_GrPixelConfig);
GR_STATIC_ASSERT(9 == kLATC_GrPixelConfig);
GR_STATIC_ASSERT(10 == kR11_EAC_GrPixelConfig);
GR_STATIC_ASSERT(11 == kASTC_12x12_GrPixelConfig);
GR_STATIC_ASSERT(12 == kRGBA_float_GrPixelConfig);
GR_STATIC_ASSERT(13 == kAlpha_half_GrPixelConfig);
GR_STATIC_ASSERT(SK_ARRAY_COUNT(kFlags) == kGrPixelConfigCnt);
}
#endif