1 | /* This file is part of the KDE project |
2 | * Copyright (C) 2007 Matthew Woehlke <mw_triad@users.sourceforge.net> |
3 | * Copyright (C) 2007 Thomas Zander <zander@kde.org> |
4 | * Copyright (C) 2007 Zack Rusin <zack@kde.org> |
5 | * |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Library General Public |
8 | * License as published by the Free Software Foundation; either |
9 | * version 2 of the License, or (at your option) any later version. |
10 | * |
11 | * This library is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | * Library General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU Library General Public License |
17 | * along with this library; see the file COPYING.LIB. If not, write to |
18 | * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
19 | * Boston, MA 02110-1301, USA. |
20 | */ |
21 | |
22 | #ifndef KCOLORUTILS_H |
23 | #define KCOLORUTILS_H |
24 | |
25 | #include <kdeui_export.h> |
26 | #include <QtGui/QPainter> |
27 | |
28 | class QColor; |
29 | |
30 | /** |
31 | * A set of methods used to work with colors. |
32 | */ |
33 | namespace KColorUtils { |
34 | /** |
35 | * Calculate the luma of a color. Luma is weighted sum of gamma-adjusted |
36 | * R'G'B' components of a color. The result is similar to qGray. The range |
37 | * is from 0.0 (black) to 1.0 (white). |
38 | * |
39 | * KColorUtils::darken(), KColorUtils::lighten() and KColorUtils::shade() |
40 | * operate on the luma of a color. |
41 | * |
42 | * @see http://en.wikipedia.org/wiki/Luma_(video) |
43 | */ |
44 | KDEUI_EXPORT qreal luma(const QColor&); |
45 | |
46 | /** |
47 | * Calculate the contrast ratio between two colors, according to the |
48 | * W3C/WCAG2.0 algorithm, (Lmax + 0.05)/(Lmin + 0.05), where Lmax and Lmin |
49 | * are the luma values of the lighter color and the darker color, |
50 | * respectively. |
51 | * |
52 | * A contrast ration of 5:1 (result == 5.0) is the minimum for "normal" |
53 | * text to be considered readable (large text can go as low as 3:1). The |
54 | * ratio ranges from 1:1 (result == 1.0) to 21:1 (result == 21.0). |
55 | * |
56 | * @see KColorUtils::luma |
57 | */ |
58 | KDEUI_EXPORT qreal contrastRatio(const QColor&, const QColor&); |
59 | |
60 | /** |
61 | * Adjust the luma of a color by changing its distance from white. |
62 | * |
63 | * @li amount == 1.0 gives white |
64 | * @li amount == 0.5 results in a color whose luma is halfway between 1.0 |
65 | * and that of the original color |
66 | * @li amount == 0.0 gives the original color |
67 | * @li amount == -1.0 gives a color that is 'twice as far from white' as |
68 | * the original color, that is luma(result) == 1.0 - 2*(1.0 - luma(color)) |
69 | * |
70 | * @param amount factor by which to adjust the luma component of the color |
71 | * @param chromaInverseGain (optional) factor by which to adjust the chroma |
72 | * component of the color; 1.0 means no change, 0.0 maximizes chroma |
73 | * @see KColorUtils::shade |
74 | */ |
75 | KDEUI_EXPORT QColor lighten(const QColor&, qreal amount = 0.5, qreal chromaInverseGain = 1.0); |
76 | |
77 | /** |
78 | * Adjust the luma of a color by changing its distance from black. |
79 | * |
80 | * @li amount == 1.0 gives black |
81 | * @li amount == 0.5 results in a color whose luma is halfway between 0.0 |
82 | * and that of the original color |
83 | * @li amount == 0.0 gives the original color |
84 | * @li amount == -1.0 gives a color that is 'twice as far from black' as |
85 | * the original color, that is luma(result) == 2*luma(color) |
86 | * |
87 | * @param amount factor by which to adjust the luma component of the color |
88 | * @param chromaGain (optional) factor by which to adjust the chroma |
89 | * component of the color; 1.0 means no change, 0.0 minimizes chroma |
90 | * @see KColorUtils::shade |
91 | */ |
92 | KDEUI_EXPORT QColor darken(const QColor&, qreal amount = 0.5, qreal chromaGain = 1.0); |
93 | |
94 | /** |
95 | * Adjust the luma and chroma components of a color. The amount is added |
96 | * to the corresponding component. |
97 | * |
98 | * @param lumaAmount amount by which to adjust the luma component of the |
99 | * color; 0.0 results in no change, -1.0 turns anything black, 1.0 turns |
100 | * anything white |
101 | * @param chromaAmount (optional) amount by which to adjust the chroma |
102 | * component of the color; 0.0 results in no change, -1.0 minimizes chroma, |
103 | * 1.0 maximizes chroma |
104 | * @see KColorUtils::luma |
105 | */ |
106 | KDEUI_EXPORT QColor shade(const QColor&, qreal lumaAmount, qreal chromaAmount = 0.0); |
107 | |
108 | /** |
109 | * Create a new color by tinting one color with another. This function is |
110 | * meant for creating additional colors withing the same class (background, |
111 | * foreground) from colors in a different class. Therefore when @p amount |
112 | * is low, the luma of @p base is mostly preserved, while the hue and |
113 | * chroma of @p color is mostly inherited. |
114 | * |
115 | * @param base color to be tinted |
116 | * @param color color with which to tint |
117 | * @param amount how strongly to tint the base; 0.0 gives @p base, |
118 | * 1.0 gives @p color |
119 | */ |
120 | KDEUI_EXPORT QColor tint(const QColor &base, const QColor &color, qreal amount = 0.3); |
121 | |
122 | /** |
123 | * Blend two colors into a new color by linear combination. |
124 | * @code |
125 | QColor lighter = KColorUtils::mix(myColor, Qt::white) |
126 | * @endcode |
127 | * @param c1 first color. |
128 | * @param c2 second color. |
129 | * @param bias weight to be used for the mix. @p bias <= 0 gives @p c1, |
130 | * @p bias >= 1 gives @p c2. @p bias == 0.5 gives a 50% blend of @p c1 |
131 | * and @p c2. |
132 | */ |
133 | KDEUI_EXPORT QColor mix(const QColor &c1, const QColor &c2, |
134 | qreal bias = 0.5); |
135 | |
136 | /** |
137 | * Blend two colors into a new color by painting the second color over the |
138 | * first using the specified composition mode. |
139 | * @code |
140 | QColor white(Qt::white); |
141 | white.setAlphaF(0.5); |
142 | QColor lighter = KColorUtils::overlayColors(myColor, white); |
143 | @endcode |
144 | * @param base the base color (alpha channel is ignored). |
145 | * @param paint the color to be overlayed onto the base color. |
146 | * @param comp the CompositionMode used to do the blending. |
147 | */ |
148 | KDEUI_EXPORT QColor overlayColors(const QColor &base, const QColor &paint, |
149 | QPainter::CompositionMode comp = QPainter::CompositionMode_SourceOver); |
150 | |
151 | } |
152 | |
153 | #endif // KCOLORUTILS_H |
154 | // kate: space-indent on; indent-width 4; replace-tabs on; auto-insert-doxygen on; |
155 | |