The Tor Browser: gfx/thebes/gfxColor.h@b8a032363ba2 (annotated)

gfx/thebes/gfxColor.h@b8a032363ba2 (annotated)

gfx/thebes/gfxColor.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

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

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gfx/thebes/gfxColor.h@b8a032363ba2 (annotated)

gfx/thebes/gfxColor.h