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Diffstat (limited to 'uisimulator/alpha.c')
-rw-r--r-- | uisimulator/alpha.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/uisimulator/alpha.c b/uisimulator/alpha.c new file mode 100644 index 0000000000..22504fcd93 --- /dev/null +++ b/uisimulator/alpha.c | |||
@@ -0,0 +1,215 @@ | |||
1 | /* xscreensaver, Copyright (c) 1992, 1995, 1996, 1997 | ||
2 | * Jamie Zawinski <jwz@jwz.org> | ||
3 | * | ||
4 | * Permission to use, copy, modify, distribute, and sell this software and its | ||
5 | * documentation for any purpose is hereby granted without fee, provided that | ||
6 | * the above copyright notice appear in all copies and that both that | ||
7 | * copyright notice and this permission notice appear in supporting | ||
8 | * documentation. No representations are made about the suitability of this | ||
9 | * software for any purpose. It is provided "as is" without express or | ||
10 | * implied warranty. | ||
11 | */ | ||
12 | |||
13 | /* Beauty is only skin deep, unless you've got an alpha channel. */ | ||
14 | |||
15 | |||
16 | #include "utils.h" | ||
17 | #include "alpha.h" | ||
18 | #include "visual.h" | ||
19 | #include "hsv.h" | ||
20 | #include "yarandom.h" | ||
21 | #include "resources.h" | ||
22 | |||
23 | #include <X11/Xutil.h> | ||
24 | |||
25 | #ifndef countof | ||
26 | # define countof(x) (sizeof(*(x))/sizeof((x))) | ||
27 | #endif | ||
28 | |||
29 | |||
30 | /* I don't believe this fucking language doesn't have builtin exponentiation. | ||
31 | I further can't believe that the fucking ^ character means fucking XOR!! */ | ||
32 | static int | ||
33 | i_exp (int i, int j) | ||
34 | { | ||
35 | int k = 1; | ||
36 | while (j--) k *= i; | ||
37 | return k; | ||
38 | } | ||
39 | |||
40 | |||
41 | static void | ||
42 | merge_colors (int argc, XColor **argv, XColor *into_color, int mask, | ||
43 | Bool additive_p) | ||
44 | { | ||
45 | int j; | ||
46 | *into_color = *argv [0]; | ||
47 | into_color->pixel |= mask; | ||
48 | |||
49 | for (j = 1; j < argc; j++) | ||
50 | { | ||
51 | # define SHORT_INC(x,y) (x = ((((x)+(y)) > 0xFFFF) ? 0xFFFF : ((x)+(y)))) | ||
52 | # define SHORT_DEC(x,y) (x = ((((x)-(y)) < 0) ? 0 : ((x)-(y)))) | ||
53 | if (additive_p) | ||
54 | { | ||
55 | SHORT_INC (into_color->red, argv[j]->red); | ||
56 | SHORT_INC (into_color->green, argv[j]->green); | ||
57 | SHORT_INC (into_color->blue, argv[j]->blue); | ||
58 | } | ||
59 | else | ||
60 | { | ||
61 | SHORT_DEC (into_color->red, argv[j]->red); | ||
62 | SHORT_DEC (into_color->green, argv[j]->green); | ||
63 | SHORT_DEC (into_color->blue, argv[j]->blue); | ||
64 | } | ||
65 | # undef SHORT_INC | ||
66 | # undef SHORT_DEC | ||
67 | } | ||
68 | } | ||
69 | |||
70 | static void | ||
71 | permute_colors (XColor *pcolors, XColor *colors, | ||
72 | int count, | ||
73 | unsigned long *plane_masks, | ||
74 | Bool additive_p) | ||
75 | { | ||
76 | int out = 0; | ||
77 | int max = i_exp (2, count); | ||
78 | if (count > 31) abort (); | ||
79 | for (out = 1; out < max; out++) | ||
80 | { | ||
81 | XColor *argv [32]; | ||
82 | int this_mask = 0; | ||
83 | int argc = 0; | ||
84 | int bit; | ||
85 | for (bit = 0; bit < 32; bit++) | ||
86 | if (out & (1<<bit)) | ||
87 | { | ||
88 | argv [argc++] = &pcolors [bit]; | ||
89 | this_mask |= plane_masks [bit]; | ||
90 | } | ||
91 | merge_colors (argc, argv, &colors [out-1], this_mask, additive_p); | ||
92 | } | ||
93 | } | ||
94 | |||
95 | |||
96 | static int | ||
97 | allocate_color_planes (Display *dpy, Colormap cmap, | ||
98 | int nplanes, unsigned long *plane_masks, | ||
99 | unsigned long *base_pixel_ret) | ||
100 | { | ||
101 | while (nplanes > 1 && | ||
102 | !XAllocColorCells (dpy, cmap, False, plane_masks, nplanes, | ||
103 | base_pixel_ret, 1)) | ||
104 | nplanes--; | ||
105 | |||
106 | return nplanes; | ||
107 | } | ||
108 | |||
109 | |||
110 | static void | ||
111 | initialize_transparency_colormap (Display *dpy, Colormap cmap, | ||
112 | int nplanes, | ||
113 | unsigned long base_pixel, | ||
114 | unsigned long *plane_masks, | ||
115 | XColor *colors, | ||
116 | Bool additive_p) | ||
117 | { | ||
118 | int i; | ||
119 | int total_colors = i_exp (2, nplanes); | ||
120 | XColor *all_colors = (XColor *) calloc (total_colors, sizeof (XColor)); | ||
121 | |||
122 | for (i = 0; i < nplanes; i++) | ||
123 | colors[i].pixel = base_pixel | plane_masks [i]; | ||
124 | permute_colors (colors, all_colors, nplanes, plane_masks, additive_p); | ||
125 | |||
126 | /* clone the default background of the window into our "base" pixel */ | ||
127 | all_colors [total_colors - 1].pixel = | ||
128 | get_pixel_resource ("background", "Background", dpy, cmap); | ||
129 | XQueryColor (dpy, cmap, &all_colors [total_colors - 1]); | ||
130 | all_colors [total_colors - 1].pixel = base_pixel; | ||
131 | |||
132 | for (i = 0; i < total_colors; i++) | ||
133 | all_colors[i].flags = DoRed|DoGreen|DoBlue; | ||
134 | XStoreColors (dpy, cmap, all_colors, total_colors); | ||
135 | XFree ((XPointer) all_colors); | ||
136 | } | ||
137 | |||
138 | |||
139 | Bool | ||
140 | allocate_alpha_colors (Screen *screen, Visual *visual, Colormap cmap, | ||
141 | int *nplanesP, Bool additive_p, | ||
142 | unsigned long **plane_masks, | ||
143 | unsigned long *base_pixelP) | ||
144 | { | ||
145 | Display *dpy = DisplayOfScreen (screen); | ||
146 | XColor *colors; | ||
147 | int nplanes = *nplanesP; | ||
148 | int i; | ||
149 | |||
150 | if (!has_writable_cells (screen, visual)) | ||
151 | cmap = 0; | ||
152 | |||
153 | if (!cmap) /* A TrueColor visual, or similar. */ | ||
154 | { | ||
155 | int depth = visual_depth (screen, visual); | ||
156 | unsigned long masks; | ||
157 | XVisualInfo vi_in, *vi_out; | ||
158 | |||
159 | /* Find out which bits the R, G, and B components actually occupy | ||
160 | on this visual. */ | ||
161 | vi_in.screen = screen_number (screen); | ||
162 | vi_in.visualid = XVisualIDFromVisual (visual); | ||
163 | vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask, | ||
164 | &vi_in, &i); | ||
165 | if (! vi_out) abort (); | ||
166 | masks = vi_out[0].red_mask | vi_out[0].green_mask | vi_out[0].blue_mask; | ||
167 | XFree ((char *) vi_out); | ||
168 | |||
169 | if (nplanes > depth) | ||
170 | nplanes = depth; | ||
171 | *nplanesP = nplanes; | ||
172 | *base_pixelP = 0; | ||
173 | *plane_masks = (unsigned long *) calloc(sizeof(unsigned long), nplanes); | ||
174 | |||
175 | /* Pick the planar values randomly, but constrain them to fall within | ||
176 | the bit positions of the R, G, and B fields. */ | ||
177 | for (i = 0; i < nplanes; i++) | ||
178 | (*plane_masks)[i] = random() & masks; | ||
179 | |||
180 | } | ||
181 | else /* A PseudoColor visual, or similar. */ | ||
182 | { | ||
183 | if (nplanes > 31) nplanes = 31; | ||
184 | *plane_masks = (unsigned long *) malloc(sizeof(unsigned long) * nplanes); | ||
185 | |||
186 | nplanes = allocate_color_planes (dpy, cmap, nplanes, *plane_masks, | ||
187 | base_pixelP); | ||
188 | *nplanesP = nplanes; | ||
189 | |||
190 | if (nplanes <= 1) | ||
191 | { | ||
192 | free(*plane_masks); | ||
193 | *plane_masks = 0; | ||
194 | return False; | ||
195 | } | ||
196 | |||
197 | colors = (XColor *) calloc (nplanes, sizeof (XColor)); | ||
198 | for (i = 0; i < nplanes; i++) | ||
199 | { | ||
200 | /* pick the base colors. If we are in subtractive mode, pick higher | ||
201 | intensities. */ | ||
202 | hsv_to_rgb (random () % 360, | ||
203 | frand (1.0), | ||
204 | frand (0.5) + (additive_p ? 0.2 : 0.5), | ||
205 | &colors[i].red, | ||
206 | &colors[i].green, | ||
207 | &colors[i].blue); | ||
208 | } | ||
209 | initialize_transparency_colormap (dpy, cmap, nplanes, | ||
210 | *base_pixelP, *plane_masks, colors, | ||
211 | additive_p); | ||
212 | XFree ((XPointer) colors); | ||
213 | } | ||
214 | return True; | ||
215 | } | ||