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228 lines
7.1 KiB
C
228 lines
7.1 KiB
C
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef GFX_COLOR_H
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#define GFX_COLOR_H
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#include "gfxTypes.h"
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#include "mozilla/Attributes.h" // for MOZ_ALWAYS_INLINE
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#include "mozilla/Endian.h" // for mozilla::NativeEndian::swapToBigEndian
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#define GFX_UINT32_FROM_BPTR(pbptr,i) (((uint32_t*)(pbptr))[i])
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/**
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* GFX_0XFF_PPIXEL_FROM_BPTR(x)
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*
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* Avoid tortured construction of 32-bit ARGB pixel from 3 individual bytes
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* of memory plus constant 0xFF. RGB bytes are already contiguous!
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* Equivalent to: GFX_PACKED_PIXEL(0xff,r,g,b)
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*
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* Attempt to use fast byte-swapping instruction(s), e.g. bswap on x86, in
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* preference to a sequence of shift/or operations.
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*/
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#define GFX_0XFF_PPIXEL_FROM_UINT32(x) \
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( (mozilla::NativeEndian::swapToBigEndian(uint32_t(x)) >> 8) | (0xFFU << 24) )
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#define GFX_0XFF_PPIXEL_FROM_BPTR(x) \
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( GFX_0XFF_PPIXEL_FROM_UINT32(GFX_UINT32_FROM_BPTR((x),0)) )
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/**
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* GFX_BLOCK_RGB_TO_FRGB(from,to)
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* sizeof(*from) == sizeof(char)
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* sizeof(*to) == sizeof(uint32_t)
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*
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* Copy 4 pixels at a time, reading blocks of 12 bytes (RGB x4)
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* and writing blocks of 16 bytes (FRGB x4)
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*/
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#define GFX_BLOCK_RGB_TO_FRGB(from,to) \
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PR_BEGIN_MACRO \
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uint32_t m0 = GFX_UINT32_FROM_BPTR(from,0), \
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m1 = GFX_UINT32_FROM_BPTR(from,1), \
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m2 = GFX_UINT32_FROM_BPTR(from,2), \
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rgbr = mozilla::NativeEndian::swapToBigEndian(m0), \
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gbrg = mozilla::NativeEndian::swapToBigEndian(m1), \
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brgb = mozilla::NativeEndian::swapToBigEndian(m2), \
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p0, p1, p2, p3; \
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p0 = 0xFF000000 | ((rgbr) >> 8); \
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p1 = 0xFF000000 | ((rgbr) << 16) | ((gbrg) >> 16); \
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p2 = 0xFF000000 | ((gbrg) << 8) | ((brgb) >> 24); \
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p3 = 0xFF000000 | (brgb); \
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to[0] = p0; to[1] = p1; to[2] = p2; to[3] = p3; \
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PR_END_MACRO
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/**
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* Fast approximate division by 255. It has the property that
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* for all 0 <= n <= 255*255, GFX_DIVIDE_BY_255(n) == n/255.
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* But it only uses two adds and two shifts instead of an
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* integer division (which is expensive on many processors).
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*
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* equivalent to ((v)/255)
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*/
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#define GFX_DIVIDE_BY_255(v) \
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(((((unsigned)(v)) << 8) + ((unsigned)(v)) + 255) >> 16)
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/**
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* Fast premultiply
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*
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* equivalent to (((c)*(a))/255)
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*/
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uint8_t MOZ_ALWAYS_INLINE gfxPreMultiply(uint8_t c, uint8_t a) {
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return GFX_DIVIDE_BY_255((c)*(a));
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}
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/**
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* Pack the 4 8-bit channels (A,R,G,B)
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* into a 32-bit packed NON-premultiplied pixel.
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*/
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uint32_t MOZ_ALWAYS_INLINE
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gfxPackedPixelNoPreMultiply(uint8_t a, uint8_t r, uint8_t g, uint8_t b) {
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return (((a) << 24) | ((r) << 16) | ((g) << 8) | (b));
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}
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/**
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* Pack the 4 8-bit channels (A,R,G,B)
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* into a 32-bit packed premultiplied pixel.
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*/
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uint32_t MOZ_ALWAYS_INLINE
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gfxPackedPixel(uint8_t a, uint8_t r, uint8_t g, uint8_t b) {
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if (a == 0x00)
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return 0x00000000;
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else if (a == 0xFF) {
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return gfxPackedPixelNoPreMultiply(a, r, g, b);
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} else {
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return ((a) << 24) |
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(gfxPreMultiply(r,a) << 16) |
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(gfxPreMultiply(g,a) << 8) |
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(gfxPreMultiply(b,a));
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}
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}
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/**
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* A color value, storing red, green, blue and alpha components.
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* This class does not use premultiplied alpha.
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*
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* XXX should this use doubles (instead of gfxFloat), for consistency with
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* cairo?
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*/
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struct gfxRGBA {
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gfxFloat r, g, b, a;
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enum PackedColorType {
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PACKED_ABGR,
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PACKED_ABGR_PREMULTIPLIED,
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PACKED_ARGB,
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PACKED_ARGB_PREMULTIPLIED,
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PACKED_XRGB
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};
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gfxRGBA() { }
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/**
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* Intialize this color using explicit red, green, blue and alpha
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* values.
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*/
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MOZ_CONSTEXPR gfxRGBA(gfxFloat _r, gfxFloat _g, gfxFloat _b, gfxFloat _a=1.0) : r(_r), g(_g), b(_b), a(_a) {}
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/**
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* Initialize this color from a packed 32-bit color.
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* The color value is interpreted based on colorType;
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* all values use the native platform endianness.
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*
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* Resulting gfxRGBA stores non-premultiplied data.
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*
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* @see gfxRGBA::Packed
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*/
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gfxRGBA(uint32_t c, PackedColorType colorType = PACKED_ABGR) {
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if (colorType == PACKED_ABGR ||
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colorType == PACKED_ABGR_PREMULTIPLIED)
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{
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r = ((c >> 0) & 0xff) * (1.0 / 255.0);
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g = ((c >> 8) & 0xff) * (1.0 / 255.0);
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b = ((c >> 16) & 0xff) * (1.0 / 255.0);
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a = ((c >> 24) & 0xff) * (1.0 / 255.0);
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} else if (colorType == PACKED_ARGB ||
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colorType == PACKED_XRGB ||
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colorType == PACKED_ARGB_PREMULTIPLIED)
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{
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b = ((c >> 0) & 0xff) * (1.0 / 255.0);
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g = ((c >> 8) & 0xff) * (1.0 / 255.0);
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r = ((c >> 16) & 0xff) * (1.0 / 255.0);
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a = ((c >> 24) & 0xff) * (1.0 / 255.0);
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}
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if (colorType == PACKED_ABGR_PREMULTIPLIED ||
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colorType == PACKED_ARGB_PREMULTIPLIED)
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{
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if (a > 0.0) {
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r /= a;
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g /= a;
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b /= a;
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}
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} else if (colorType == PACKED_XRGB) {
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a = 1.0;
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}
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}
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bool operator==(const gfxRGBA& other) const
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{
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return r == other.r && g == other.g && b == other.b && a == other.a;
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}
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bool operator!=(const gfxRGBA& other) const
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{
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return !(*this == other);
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}
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/**
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* Returns this color value as a packed 32-bit integer. This reconstructs
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* the int32_t based on the given colorType, always in the native byte order.
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*
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* Note: gcc 4.2.3 on at least Ubuntu (x86) does something strange with
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* (uint8_t)(c * 255.0) << x, where the result is different than
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* double d = c * 255.0; v = ((uint8_t) d) << x.
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*/
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uint32_t Packed(PackedColorType colorType = PACKED_ABGR) const {
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gfxFloat rb = (r * 255.0);
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gfxFloat gb = (g * 255.0);
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gfxFloat bb = (b * 255.0);
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gfxFloat ab = (a * 255.0);
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if (colorType == PACKED_ABGR) {
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return (uint8_t(ab) << 24) |
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(uint8_t(bb) << 16) |
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(uint8_t(gb) << 8) |
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(uint8_t(rb) << 0);
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}
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if (colorType == PACKED_ARGB || colorType == PACKED_XRGB) {
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return (uint8_t(ab) << 24) |
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(uint8_t(rb) << 16) |
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(uint8_t(gb) << 8) |
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(uint8_t(bb) << 0);
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}
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rb *= a;
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gb *= a;
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bb *= a;
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if (colorType == PACKED_ABGR_PREMULTIPLIED) {
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return (((uint8_t)(ab) << 24) |
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((uint8_t)(bb) << 16) |
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((uint8_t)(gb) << 8) |
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((uint8_t)(rb) << 0));
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}
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if (colorType == PACKED_ARGB_PREMULTIPLIED) {
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return (((uint8_t)(ab) << 24) |
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((uint8_t)(rb) << 16) |
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((uint8_t)(gb) << 8) |
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((uint8_t)(bb) << 0));
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}
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return 0;
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}
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};
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#endif /* _GFX_COLOR_H */
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