gecko/gfx/thebes/public/gfxColor.h

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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Oracle Corporation code.
*
* The Initial Developer of the Original Code is Oracle Corporation.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Stuart Parmenter <pavlov@pavlov.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef GFX_COLOR_H
#define GFX_COLOR_H
#ifdef MOZILLA_INTERNAL_API
#include "nsPrintfCString.h"
#endif
#include "gfxTypes.h"
#include "prbit.h" // for PR_ROTATE_(LEFT,RIGHT)32
#include "prio.h" // for ntohl
#define GFX_UINT32_FROM_BPTR(pbptr,i) (((PRUint32*)(pbptr))[i])
#if defined(IS_BIG_ENDIAN)
#define GFX_NTOHL(x) (x)
#define GFX_HAVE_CHEAP_NTOHL
#elif defined(_WIN32)
#if (_MSC_VER >= 1300) // also excludes MinGW
#include <stdlib.h>
#pragma intrinsic(_byteswap_ulong)
#define GFX_NTOHL(x) _byteswap_ulong(x)
#define GFX_HAVE_CHEAP_NTOHL
#else
// A reasonably fast generic little-endian implementation.
#define GFX_NTOHL(x) \
( (PR_ROTATE_RIGHT32((x),8) & 0xFF00FF00) | \
(PR_ROTATE_LEFT32((x),8) & 0x00FF00FF) )
#endif
#else
#define GFX_NTOHL(x) ntohl(x)
#define GFX_HAVE_CHEAP_NTOHL
#endif
/**
* 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.
*/
#if defined(GFX_HAVE_CHEAP_NTOHL)
#define GFX_0XFF_PPIXEL_FROM_UINT32(x) \
( (GFX_NTOHL(x) >> 8) | (0xFF << 24) )
#else
// A reasonably fast generic little-endian implementation.
#define GFX_0XFF_PPIXEL_FROM_UINT32(x) \
( (PR_ROTATE_LEFT32((x),16) | 0xFF00FF00) & ((x) | 0xFFFF00FF) )
#endif
#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(PRUint32)
*
* 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 \
PRUint32 m0 = GFX_UINT32_FROM_BPTR(from,0), \
m1 = GFX_UINT32_FROM_BPTR(from,1), \
m2 = GFX_UINT32_FROM_BPTR(from,2), \
rgbr = GFX_NTOHL(m0), \
gbrg = GFX_NTOHL(m1), \
brgb = GFX_NTOHL(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 macro
*
* equivalent to (((c)*(a))/255)
*/
#define GFX_PREMULTIPLY(c,a) GFX_DIVIDE_BY_255((c)*(a))
/**
* Macro to pack the 4 8-bit channels (A,R,G,B)
* into a 32-bit packed premultiplied pixel.
*
* The checks for 0 alpha or max alpha ensure that the
* compiler selects the quicked calculation when alpha is constant.
*/
#define GFX_PACKED_PIXEL(a,r,g,b) \
((a) == 0x00) ? 0x00000000 : \
((a) == 0xFF) ? ((0xFF << 24) | ((r) << 16) | ((g) << 8) | (b)) \
: ((a) << 24) | \
(GFX_PREMULTIPLY(r,a) << 16) | \
(GFX_PREMULTIPLY(g,a) << 8) | \
(GFX_PREMULTIPLY(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 THEBES_API gfxRGBA {
gfxFloat r, g, b, a;
enum PackedColorType {
PACKED_ABGR,
PACKED_ABGR_PREMULTIPLIED,
PACKED_ARGB,
PACKED_ARGB_PREMULTIPLIED,
PACKED_XBGR,
PACKED_XRGB
};
gfxRGBA() { }
gfxRGBA(const gfxRGBA& c) : r(c.r), g(c.g), b(c.b), a(c.a) {}
/**
* Intialize this color using explicit red, green, blue and alpha
* values.
*/
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.
*
* @see gfxRGBA::Packed
*/
gfxRGBA(PRUint32 c, PackedColorType colorType = PACKED_ABGR) {
if (colorType == PACKED_ABGR ||
colorType == PACKED_XBGR ||
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_XBGR ||
colorType == PACKED_XRGB)
{
a = 1.0;
}
}
/**
* Initialize this color by parsing the given string.
* XXX implement me!
*/
#if 0
gfxRGBA(const char* str) {
a = 1.0;
// if aString[0] is a #, parse it as hex
// if aString[0] is a letter, parse it as a color name
// if aString[0] is a number, parse it loosely as hex
}
#endif
/**
* Returns this color value as a packed 32-bit integer. This reconstructs
* the int32 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
* (PRUint8)(c * 255.0) << x, where the result is different than
* double d = c * 255.0; v = ((PRUint8) d) << x.
*/
PRUint32 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 || colorType == PACKED_XBGR) {
return (PRUint8(ab) << 24) |
(PRUint8(bb) << 16) |
(PRUint8(gb) << 8) |
(PRUint8(rb) << 0);
} else if (colorType == PACKED_ARGB || colorType == PACKED_XRGB) {
return (PRUint8(ab) << 24) |
(PRUint8(rb) << 16) |
(PRUint8(gb) << 8) |
(PRUint8(bb) << 0);
}
rb = (r*a) * 255.0;
gb = (g*a) * 255.0;
bb = (b*a) * 255.0;
if (colorType == PACKED_ABGR_PREMULTIPLIED) {
return (((PRUint8)(ab) << 24) |
((PRUint8)(bb) << 16) |
((PRUint8)(gb) << 8) |
((PRUint8)(rb) << 0));
} else if (colorType == PACKED_ARGB_PREMULTIPLIED) {
return (((PRUint8)(ab) << 24) |
((PRUint8)(rb) << 16) |
((PRUint8)(gb) << 8) |
((PRUint8)(bb) << 0));
}
return 0;
}
#ifdef MOZILLA_INTERNAL_API
/**
* Convert this color to a hex value. For example, for rgb(255,0,0),
* this will return FF0000.
*/
// XXX I'd really prefer to just have this return an nsACString
// Does this function even make sense, since we're just ignoring the alpha value?
void Hex(nsACString& result) const {
nsPrintfCString hex(8, "%02x%02x%02x", PRUint8(r*255.0), PRUint8(g*255.0), PRUint8(b*255.0));
result.Assign(hex);
}
#endif
};
#endif /* _GFX_COLOR_H */