f6de475e5c
R=bsalomon@google.com Review URL: https://codereview.chromium.org/22850006 git-svn-id: http://skia.googlecode.com/svn/trunk@10789 2bbb7eff-a529-9590-31e7-b0007b416f81
128 lines
4.4 KiB
C
128 lines
4.4 KiB
C
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/*
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* Copyright 2010 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef GrColor_DEFINED
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#define GrColor_DEFINED
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#include "GrTypes.h"
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/**
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* GrColor is 4 bytes for R, G, B, A, in a compile-time specific order. The
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* components are stored premultiplied.
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*/
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typedef uint32_t GrColor;
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// shift amount to assign a component to a GrColor int
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// These shift values are chosen for compatibility with GL attrib arrays
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// ES doesn't allow BGRA vertex attrib order so if they were not in this order
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// we'd have to swizzle in shaders. Note the assumption that the cpu is little
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// endian.
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#define GrColor_SHIFT_R 0
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#define GrColor_SHIFT_G 8
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#define GrColor_SHIFT_B 16
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#define GrColor_SHIFT_A 24
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/**
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* Pack 4 components (RGBA) into a GrColor int
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*/
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static inline GrColor GrColorPackRGBA(unsigned r, unsigned g,
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unsigned b, unsigned a) {
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SkASSERT((uint8_t)r == r);
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SkASSERT((uint8_t)g == g);
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SkASSERT((uint8_t)b == b);
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SkASSERT((uint8_t)a == a);
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return (r << GrColor_SHIFT_R) |
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(g << GrColor_SHIFT_G) |
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(b << GrColor_SHIFT_B) |
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(a << GrColor_SHIFT_A);
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}
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// extract a component (byte) from a GrColor int
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#define GrColorUnpackR(color) (((color) >> GrColor_SHIFT_R) & 0xFF)
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#define GrColorUnpackG(color) (((color) >> GrColor_SHIFT_G) & 0xFF)
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#define GrColorUnpackB(color) (((color) >> GrColor_SHIFT_B) & 0xFF)
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#define GrColorUnpackA(color) (((color) >> GrColor_SHIFT_A) & 0xFF)
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/**
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* Since premultiplied means that alpha >= color, we construct a color with
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* each component==255 and alpha == 0 to be "illegal"
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*/
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#define GrColor_ILLEGAL (~(0xFF << GrColor_SHIFT_A))
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/** Converts a GrColor to an rgba array of GrGLfloat */
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static inline void GrColorToRGBAFloat(GrColor color, float rgba[4]) {
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static const float ONE_OVER_255 = 1.f / 255.f;
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rgba[0] = GrColorUnpackR(color) * ONE_OVER_255;
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rgba[1] = GrColorUnpackG(color) * ONE_OVER_255;
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rgba[2] = GrColorUnpackB(color) * ONE_OVER_255;
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rgba[3] = GrColorUnpackA(color) * ONE_OVER_255;
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}
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/**
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* Flags used for bitfields of color components. They are defined so that the bit order reflects the
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* GrColor shift order.
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*/
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enum GrColorComponentFlags {
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kR_GrColorComponentFlag = 1 << (GrColor_SHIFT_R / 8),
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kG_GrColorComponentFlag = 1 << (GrColor_SHIFT_G / 8),
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kB_GrColorComponentFlag = 1 << (GrColor_SHIFT_B / 8),
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kA_GrColorComponentFlag = 1 << (GrColor_SHIFT_A / 8),
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kRGB_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag |
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kB_GrColorComponentFlag),
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kRGBA_GrColorComponentFlags = (kR_GrColorComponentFlag | kG_GrColorComponentFlag |
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kB_GrColorComponentFlag | kA_GrColorComponentFlag)
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};
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static inline char GrColorComponentFlagToChar(GrColorComponentFlags component) {
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SkASSERT(GrIsPow2(component));
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switch (component) {
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case kR_GrColorComponentFlag:
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return 'r';
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case kG_GrColorComponentFlag:
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return 'g';
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case kB_GrColorComponentFlag:
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return 'b';
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case kA_GrColorComponentFlag:
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return 'a';
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default:
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GrCrash("Invalid color component flag.");
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return '\0';
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}
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}
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static inline uint32_t GrPixelConfigComponentMask(GrPixelConfig config) {
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SkASSERT(config >= 0 && config < kGrPixelConfigCnt);
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static const uint32_t kFlags[] = {
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0, // kUnknown_GrPixelConfig
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kA_GrColorComponentFlag, // kAlpha_8_GrPixelConfig
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kRGBA_GrColorComponentFlags, // kIndex_8_GrPixelConfig
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kRGB_GrColorComponentFlags, // kRGB_565_GrPixelConfig
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kRGBA_GrColorComponentFlags, // kRGBA_4444_GrPixelConfig
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kRGBA_GrColorComponentFlags, // kRGBA_8888_GrPixelConfig
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kRGBA_GrColorComponentFlags, // kBGRA_8888_GrPixelConfig
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};
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return kFlags[config];
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GR_STATIC_ASSERT(0 == kUnknown_GrPixelConfig);
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GR_STATIC_ASSERT(1 == kAlpha_8_GrPixelConfig);
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GR_STATIC_ASSERT(2 == kIndex_8_GrPixelConfig);
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GR_STATIC_ASSERT(3 == kRGB_565_GrPixelConfig);
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GR_STATIC_ASSERT(4 == kRGBA_4444_GrPixelConfig);
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GR_STATIC_ASSERT(5 == kRGBA_8888_GrPixelConfig);
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GR_STATIC_ASSERT(6 == kBGRA_8888_GrPixelConfig);
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GR_STATIC_ASSERT(SK_ARRAY_COUNT(kFlags) == kGrPixelConfigCnt);
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}
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#endif
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