1 /*
2 * Copyright 2001-2006, Haiku.
3 * Distributed under the terms of the MIT License.
4 *
5 * Authors:
6 * DarkWyrm <bpmagic@columbus.rr.com>
7 * Stefano Ceccherini (burton666@libero.it)
8 */
9
10 //! Methods to initialize and get the system color_map.
11
12
13 #include <GraphicsDefs.h>
14 #include <InterfaceDefs.h>
15
16 #include <Palette.h>
17
18 // TODO: BWindowScreen has a method to set the palette.
19 // maybe we should have a lock to protect this variable.
20 static color_map sColorMap;
21
22
23 // color_distance
24 /*! \brief Returns the "distance" between two RGB colors.
25
26 This functions defines an metric on the RGB color space. The distance
27 between two colors is 0, if and only if the colors are equal.
28
29 \param red1 Red component of the first color.
30 \param green1 Green component of the first color.
31 \param blue1 Blue component of the first color.
32 \param red2 Red component of the second color.
33 \param green2 Green component of the second color.
34 \param blue2 Blue component of the second color.
35 \return The distance between the given colors.
36 */
37 static inline uint32
color_distance(uint8 red1,uint8 green1,uint8 blue1,uint8 red2,uint8 green2,uint8 blue2)38 color_distance(uint8 red1, uint8 green1, uint8 blue1,
39 uint8 red2, uint8 green2, uint8 blue2)
40 {
41 int rd = (int)red1 - (int)red2;
42 int gd = (int)green1 - (int)green2;
43 int bd = (int)blue1 - (int)blue2;
44
45 // distance according to psycho-visual tests
46 // algorithm taken from here:
47 // http://www.stud.uni-hannover.de/~michaelt/juggle/Algorithms.pdf
48 int rmean = ((int)red1 + (int)red2) / 2;
49 return (((512 + rmean) * rd * rd) >> 8)
50 + 4 * gd * gd
51 + (((767 - rmean) * bd * bd) >> 8);
52 }
53
54
55 static inline uint8
FindClosestColor(const rgb_color & color,const rgb_color * palette)56 FindClosestColor(const rgb_color &color, const rgb_color *palette)
57 {
58 uint8 closestIndex = 0;
59 unsigned closestDistance = UINT_MAX;
60 for (int32 i = 0; i < 256; i++) {
61 const rgb_color &c = palette[i];
62 unsigned distance = color_distance(color.red, color.green, color.blue,
63 c.red, c.green, c.blue);
64 if (distance < closestDistance) {
65 closestIndex = (uint8)i;
66 closestDistance = distance;
67 }
68 }
69 return closestIndex;
70 }
71
72
73 static inline rgb_color
InvertColor(const rgb_color & color)74 InvertColor(const rgb_color &color)
75 {
76 // For some reason, Inverting (255, 255, 255) on beos
77 // results in the same color.
78 if (color.red == 255 && color.green == 255
79 && color.blue == 255)
80 return color;
81
82 rgb_color inverted;
83 inverted.red = 255 - color.red;
84 inverted.green = 255 - color.green;
85 inverted.blue = 255 - color.blue;
86 inverted.alpha = 255;
87
88 return inverted;
89 }
90
91
92 static void
FillColorMap(const rgb_color * palette,color_map * map)93 FillColorMap(const rgb_color *palette, color_map *map)
94 {
95 memcpy(map->color_list, palette, sizeof(map->color_list));
96
97 // init index map
98 for (int32 color = 0; color < 32768; color++) {
99 // get components
100 rgb_color rgbColor;
101 rgbColor.red = (color & 0x7c00) >> 7;
102 rgbColor.green = (color & 0x3e0) >> 2;
103 rgbColor.blue = (color & 0x1f) << 3;
104
105 map->index_map[color] = FindClosestColor(rgbColor, palette);
106 }
107
108 // init inversion map
109 for (int32 index = 0; index < 256; index++) {
110 rgb_color inverted = InvertColor(map->color_list[index]);
111 map->inversion_map[index] = FindClosestColor(inverted, palette);
112 }
113 }
114
115
116 const color_map *
system_colors()117 system_colors()
118 {
119 static bool sInitialized = false;
120 if (!sInitialized) {
121 FillColorMap(kSystemPalette, &sColorMap);
122 sInitialized = true;
123 }
124
125 return &sColorMap;
126 }
127