[36] | 1 | /* |
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[186] | 2 | * libcaca ASCII-Art library |
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[98] | 3 | * Copyright (c) 2002, 2003 Sam Hocevar <sam@zoy.org> |
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[36] | 4 | * All Rights Reserved |
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| 5 | * |
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[80] | 6 | * $Id: conic.c 188 2003-11-16 11:26:54Z sam $ |
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[36] | 7 | * |
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| 8 | * This program is free software; you can redistribute it and/or modify |
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| 9 | * it under the terms of the GNU General Public License as published by |
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| 10 | * the Free Software Foundation; either version 2 of the License, or |
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| 11 | * (at your option) any later version. |
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| 12 | * |
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| 13 | * This program is distributed in the hope that it will be useful, |
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| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 16 | * GNU General Public License for more details. |
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| 17 | * |
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| 18 | * You should have received a copy of the GNU General Public License |
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| 19 | * along with this program; if not, write to the Free Software |
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| 20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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| 21 | */ |
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[18] | 22 | |
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[98] | 23 | #include "config.h" |
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| 24 | |
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[156] | 25 | #ifdef HAVE_INTTYPES_H |
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| 26 | # include <inttypes.h> |
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| 27 | #else |
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| 28 | typedef unsigned char uint8_t; |
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| 29 | #endif |
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| 30 | |
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[18] | 31 | #include <stdlib.h> |
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| 32 | |
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[186] | 33 | #include "caca.h" |
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| 34 | #include "caca_internals.h" |
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[18] | 35 | |
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[136] | 36 | static void ellipsepoints(int, int, int, int, char); |
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| 37 | |
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[186] | 38 | void caca_draw_circle(int x, int y, int r, char c) |
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[18] | 39 | { |
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| 40 | int test, dx, dy; |
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| 41 | |
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| 42 | /* Optimized Bresenham. Kick ass. */ |
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[88] | 43 | for(test = 0, dx = 0, dy = r ; dx <= dy ; dx++) |
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[18] | 44 | { |
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[136] | 45 | ellipsepoints(x, y, dx, dy, c); |
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| 46 | ellipsepoints(x, y, dy, dx, c); |
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[18] | 47 | |
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| 48 | test += test > 0 ? dx - dy-- : dx; |
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| 49 | } |
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| 50 | } |
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| 51 | |
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[186] | 52 | void caca_fill_ellipse(int xo, int yo, int a, int b, char c) |
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[152] | 53 | { |
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| 54 | int d2; |
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| 55 | int x = 0; |
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| 56 | int y = b; |
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| 57 | int d1 = b*b - (a*a*b) + (a*a/4); |
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| 58 | |
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[166] | 59 | while(a*a*y - a*a/2 > b*b*(x+1)) |
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[152] | 60 | { |
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| 61 | if(d1 < 0) |
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| 62 | { |
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| 63 | d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */ |
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| 64 | } |
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| 65 | else |
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| 66 | { |
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| 67 | d1 += b*b*(2*x*1) + a*a*(-2*y+2); |
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[186] | 68 | caca_draw_line(xo - x, yo - y, xo + x, yo - y, c); |
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| 69 | caca_draw_line(xo - x, yo + y, xo + x, yo + y, c); |
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[152] | 70 | y--; |
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| 71 | } |
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| 72 | x++; |
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| 73 | } |
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| 74 | |
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[186] | 75 | caca_draw_line(xo - x, yo - y, xo + x, yo - y, c); |
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| 76 | caca_draw_line(xo - x, yo + y, xo + x, yo + y, c); |
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[152] | 77 | |
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| 78 | d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b; |
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| 79 | while(y > 0) |
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| 80 | { |
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| 81 | if(d2 < 0) |
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| 82 | { |
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| 83 | d2 += b*b*(2*x+2) + a*a*(-2*y+3); |
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| 84 | x++; |
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| 85 | } |
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| 86 | else |
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| 87 | { |
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| 88 | d2 += a*a*(-2*y+3); |
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| 89 | } |
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| 90 | |
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| 91 | y--; |
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[186] | 92 | caca_draw_line(xo - x, yo - y, xo + x, yo - y, c); |
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| 93 | caca_draw_line(xo - x, yo + y, xo + x, yo + y, c); |
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[152] | 94 | } |
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| 95 | } |
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| 96 | |
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[186] | 97 | void caca_draw_ellipse(int xo, int yo, int a, int b, char c) |
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[132] | 98 | { |
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| 99 | int d2; |
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| 100 | int x = 0; |
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| 101 | int y = b; |
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| 102 | int d1 = b*b - (a*a*b) + (a*a/4); |
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| 103 | |
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| 104 | ellipsepoints(xo, yo, x, y, c); |
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| 105 | |
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[166] | 106 | while(a*a*y - a*a/2 > b*b*(x+1)) |
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[132] | 107 | { |
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| 108 | if(d1 < 0) |
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| 109 | { |
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| 110 | d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */ |
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| 111 | } |
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| 112 | else |
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| 113 | { |
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| 114 | d1 += b*b*(2*x*1) + a*a*(-2*y+2); |
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| 115 | y--; |
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| 116 | } |
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| 117 | x++; |
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| 118 | ellipsepoints(xo, yo, x, y, c); |
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| 119 | } |
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| 120 | |
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| 121 | d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b; |
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| 122 | while(y > 0) |
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| 123 | { |
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| 124 | if(d2 < 0) |
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| 125 | { |
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| 126 | d2 += b*b*(2*x+2) + a*a*(-2*y+3); |
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| 127 | x++; |
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| 128 | } |
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| 129 | else |
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| 130 | { |
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| 131 | d2 += a*a*(-2*y+3); |
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| 132 | } |
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| 133 | |
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| 134 | y--; |
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| 135 | ellipsepoints(xo, yo, x, y, c); |
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| 136 | } |
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| 137 | } |
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| 138 | |
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[186] | 139 | void caca_draw_thin_ellipse(int xo, int yo, int a, int b) |
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[152] | 140 | { |
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| 141 | /* FIXME: this is not correct */ |
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| 142 | int d2; |
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| 143 | int x = 0; |
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| 144 | int y = b; |
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| 145 | int d1 = b*b - (a*a*b) + (a*a/4); |
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| 146 | |
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| 147 | ellipsepoints(xo, yo, x, y, '-'); |
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| 148 | |
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[166] | 149 | while(a*a*y - a*a/2 > b*b*(x+1)) |
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[152] | 150 | { |
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| 151 | if(d1 < 0) |
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| 152 | { |
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| 153 | d1 += b*b*(2*x+1); /* XXX: "Computer Graphics" has + 3 here. */ |
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| 154 | } |
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| 155 | else |
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| 156 | { |
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| 157 | d1 += b*b*(2*x*1) + a*a*(-2*y+2); |
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| 158 | y--; |
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| 159 | } |
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| 160 | x++; |
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| 161 | ellipsepoints(xo, yo, x, y, '-'); |
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| 162 | } |
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| 163 | |
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| 164 | d2 = b*b*(x+0.5)*(x+0.5) + a*a*(y-1)*(y-1) - a*a*b*b; |
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| 165 | while(y > 0) |
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| 166 | { |
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| 167 | if(d2 < 0) |
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| 168 | { |
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| 169 | d2 += b*b*(2*x+2) + a*a*(-2*y+3); |
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| 170 | x++; |
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| 171 | } |
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| 172 | else |
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| 173 | { |
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| 174 | d2 += a*a*(-2*y+3); |
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| 175 | } |
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| 176 | |
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| 177 | y--; |
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| 178 | ellipsepoints(xo, yo, x, y, '|'); |
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| 179 | } |
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| 180 | } |
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| 181 | |
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[136] | 182 | static void ellipsepoints(int xo, int yo, int x, int y, char c) |
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| 183 | { |
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[138] | 184 | uint8_t b = 0; |
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| 185 | |
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[188] | 186 | if(xo + x >= 0 && xo + x < (int)caca_get_width()) |
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[138] | 187 | b |= 0x1; |
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[188] | 188 | if(xo - x >= 0 && xo - x < (int)caca_get_width()) |
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[138] | 189 | b |= 0x2; |
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[188] | 190 | if(yo + y >= 0 && yo + y < (int)caca_get_height()) |
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[138] | 191 | b |= 0x4; |
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[188] | 192 | if(yo - y >= 0 && yo - y < (int)caca_get_height()) |
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[138] | 193 | b |= 0x8; |
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| 194 | |
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| 195 | if((b & (0x1|0x4)) == (0x1|0x4)) |
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[186] | 196 | caca_putchar(xo + x, yo + y, c); |
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[138] | 197 | |
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| 198 | if((b & (0x2|0x4)) == (0x2|0x4)) |
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[186] | 199 | caca_putchar(xo - x, yo + y, c); |
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[138] | 200 | |
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| 201 | if((b & (0x1|0x8)) == (0x1|0x8)) |
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[186] | 202 | caca_putchar(xo + x, yo - y, c); |
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[138] | 203 | |
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| 204 | if((b & (0x2|0x8)) == (0x2|0x8)) |
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[186] | 205 | caca_putchar(xo - x, yo - y, c); |
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[136] | 206 | } |
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| 207 | |
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