qt.gui.rgb source code

1 /****************************************************************************
2 **
3 ** DQt - D bindings for the Qt Toolkit
4 **
5 ** GNU Lesser General Public License Usage
6 ** This file may be used under the terms of the GNU Lesser
7 ** General Public License version 3 as published by the Free Software
8 ** Foundation and appearing in the file LICENSE.LGPL3 included in the
9 ** packaging of this file. Please review the following information to
10 ** ensure the GNU Lesser General Public License version 3 requirements
11 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
12 **
13 ****************************************************************************/
14 module qt.gui.rgb;
15 extern(C++):
16 
17 import qt.config;
18 import qt.helpers;
19 
20 alias QRgb = uint;                        // RGB triplet
21 
22 // non-namespaced Qt global variable
23 /+ Q_DECL_UNUSED +/ __gshared const(QRgb)  RGB_MASK    = 0x00ffffff;     // masks RGB values
24 
25 pragma(inline, true) int qRed(QRgb rgb)                // get red part of RGB
26 { return ((rgb >> 16) & 0xff); }
27 
28 pragma(inline, true) int qGreen(QRgb rgb)                // get green part of RGB
29 { return ((rgb >> 8) & 0xff); }
30 
31 pragma(inline, true) int qBlue(QRgb rgb)                // get blue part of RGB
32 { return (rgb & 0xff); }
33 
34 pragma(inline, true) int qAlpha(QRgb rgb)                // get alpha part of RGBA
35 { return rgb >> 24; }
36 
37 pragma(inline, true) QRgb qRgb(int r, int g, int b)// set RGB value
38 { return (0xffu << 24) | ((r & 0xffu) << 16) | ((g & 0xffu) << 8) | (b & 0xffu); }
39 
40 pragma(inline, true) QRgb qRgba(int r, int g, int b, int a)// set RGBA value
41 { return ((a & 0xffu) << 24) | ((r & 0xffu) << 16) | ((g & 0xffu) << 8) | (b & 0xffu); }
42 
43 pragma(inline, true) int qGray(int r, int g, int b)// convert R,G,B to gray 0..255
44 { return (r*11+g*16+b*5)/32; }
45 
46 pragma(inline, true) int qGray(QRgb rgb)                // convert RGB to gray 0..255
47 { return qGray(qRed(rgb), qGreen(rgb), qBlue(rgb)); }
48 
49 pragma(inline, true) bool qIsGray(QRgb rgb)
50 { return qRed(rgb) == qGreen(rgb) && qRed(rgb) == qBlue(rgb); }
51 
52 pragma(inline, true) QRgb qPremultiply(QRgb x)
53 {
54     const(uint) a = qAlpha(x);
55     uint t = (x & 0xff00ff) * a;
56     t = (t + ((t >> 8) & 0xff00ff) + 0x800080) >> 8;
57     t &= 0xff00ff;
58 
59     x = ((x >> 8) & 0xff) * a;
60     x = (x + ((x >> 8) & 0xff) + 0x80);
61     x &= 0xff00;
62     return x | t | (a << 24);
63 }
64 
65 mixin(mangleWindows("?qt_inv_premul_factor@@3QBIB", q{
66 /+ Q_GUI_EXPORT +/ extern export __gshared const(uint)[0] qt_inv_premul_factor;
67     }));
68 
69 pragma(inline, true) QRgb qUnpremultiply(QRgb p)
70 {
71     const(uint) alpha = qAlpha(p);
72     // Alpha 255 and 0 are the two most common values, which makes them beneficial to short-cut.
73     if (alpha == 255)
74         return p;
75     if (alpha == 0)
76         return 0;
77     // (p*(0x00ff00ff/alpha)) >> 16 == (p*255)/alpha for all p and alpha <= 256.
78     const(uint) invAlpha = qt_inv_premul_factor. ptr[alpha];
79     // We add 0x8000 to get even rounding. The rounding also ensures that qPremultiply(qUnpremultiply(p)) == p for all p.
80     return qRgba((qRed(p)*invAlpha + 0x8000)>>16, (qGreen(p)*invAlpha + 0x8000)>>16, (qBlue(p)*invAlpha + 0x8000)>>16, alpha);
81 }
82