78070d8bfb
optimized. git-svn-id: svn://svn.cc65.org/cc65/trunk@4445 b7a2c559-68d2-44c3-8de9-860c34a00d81
93 lines
3.7 KiB
C
93 lines
3.7 KiB
C
/*****************************************************************************/
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/* */
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/* tgi_ellipse.c */
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/* */
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/* Draw a full ellipse */
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/* */
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/* */
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/* */
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/* (C) 2002-2009, Ullrich von Bassewitz */
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/* Roemerstrasse 52 */
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/* D-70794 Filderstadt */
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/* EMail: uz@cc65.org */
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/* */
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/* */
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/* This software is provided 'as-is', without any expressed or implied */
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/* warranty. In no event will the authors be held liable for any damages */
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/* arising from the use of this software. */
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/* */
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/* Permission is granted to anyone to use this software for any purpose, */
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/* including commercial applications, and to alter it and redistribute it */
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/* freely, subject to the following restrictions: */
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/* */
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/* 1. The origin of this software must not be misrepresented; you must not */
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/* claim that you wrote the original software. If you use this software */
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/* in a product, an acknowledgment in the product documentation would be */
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/* appreciated but is not required. */
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/* 2. Altered source versions must be plainly marked as such, and must not */
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/* be misrepresented as being the original software. */
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/* 3. This notice may not be removed or altered from any source */
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/* distribution. */
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/* */
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/*****************************************************************************/
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#include <tgi.h>
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#include <cc65.h>
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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static int RoundMul (int rhs, int lhs)
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{
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long res = cc65_imul16x16r32 (rhs, lhs);
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if ((unsigned char)res & 0x80) {
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return (int)(res >> 8) + 1;
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} else {
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return (int)(res >> 8);
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}
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}
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void __fastcall__ tgi_ellipse (int x, int y, unsigned char rx, unsigned char ry)
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/* Draw a full ellipse with center at x/y and radii rx/ry using the current
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* drawing color.
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*/
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{
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int x1, y1, x2, y2;
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unsigned angle;
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unsigned char inc;
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unsigned size = rx + ry;
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if (size >= 128) {
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inc = 12;
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} else if (size >= 32) {
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inc = 15;
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} else if (size >= 12) {
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inc = 20;
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} else {
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inc = 45;
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}
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x1 = x + rx;
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y1 = y;
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angle = 0;
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for (angle = 0; angle <= 360; angle += inc) {
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x2 = x + RoundMul (rx, cc65_cos (angle));
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y2 = y + RoundMul (ry, cc65_sin (angle));
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tgi_line (x1, y1, x2, y2);
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x1 = x2;
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y1 = y2;
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}
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}
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