1 /*****************************************************************************/
5 /* Draw an ellipse arc */
9 /* (C) 2002-2009, Ullrich von Bassewitz */
10 /* Roemerstrasse 52 */
11 /* D-70794 Filderstadt */
12 /* EMail: uz@cc65.org */
15 /* This software is provided 'as-is', without any expressed or implied */
16 /* warranty. In no event will the authors be held liable for any damages */
17 /* arising from the use of this software. */
19 /* Permission is granted to anyone to use this software for any purpose, */
20 /* including commercial applications, and to alter it and redistribute it */
21 /* freely, subject to the following restrictions: */
23 /* 1. The origin of this software must not be misrepresented; you must not */
24 /* claim that you wrote the original software. If you use this software */
25 /* in a product, an acknowledgment in the product documentation would be */
26 /* appreciated but is not required. */
27 /* 2. Altered source versions must be plainly marked as such, and must not */
28 /* be misrepresented as being the original software. */
29 /* 3. This notice may not be removed or altered from any source */
32 /*****************************************************************************/
37 #include <tgi/tgi-kernel.h>
42 /*****************************************************************************/
44 /*****************************************************************************/
48 void __fastcall__ tgi_arc (int x, int y, unsigned char rx, unsigned char ry,
49 unsigned sa, unsigned ea)
50 /* Draw an ellipse arc with center at x/y and radii rx/ry using the current
51 ** drawing color. The arc covers the angle between sa and ea (startangle and
52 ** endangle), which must be in the range 0..360 (otherwise the function may
53 ** bevave unextectedly).
58 unsigned char done = 0;
60 /* Bail out if there's nothing to do */
65 /* Determine the number of segments to use. This may be refined ... */
72 /* Calculate the start coords */
73 x1 = x + tgi_imulround (rx, _cos (sa));
74 y1 = y - tgi_imulround (ry, _sin (sa));
81 x2 = x + tgi_imulround (rx, _cos (sa));
82 y2 = y - tgi_imulround (ry, _sin (sa));
83 tgi_line (x1, y1, x2, y2);