1 #define UNICODE
2 #include <windows.h>
3 #include <math.h>
4
5 /*
6 * Rotatable Ellipse hack
7 *
8 * Win95 (Win32?) doesn't support rotating ellipses - so we
9 * implement them with polygons.
10 *
11 * We use a fixed number of edges rather than varying the number
12 * according to the radius of the ellipse.
13 * If anyone feels like improving the code (to vary the number),
14 * they should place a fixed upper bound on the number of edges
15 * since it takes a relatively long time to draw 1000 edges.
16 */
17
transformedEllipse(HDC hdc,LONG x0,LONG y0,LONG x1,LONG y1,LONG x2,LONG y2)18 int transformedEllipse(
19 HDC hdc, LONG x0, LONG y0, LONG x1, LONG y1, LONG x2, LONG y2) {
20 static BOOL firstTime = 1;
21 static double sins[20];
22 static double coss[20];
23
24 int i;
25 POINT pts[20];
26
27 double x = (x1 + x2) / 2; /* centre of parallelogram */
28 double y = (y1 + y2) / 2;
29
30 double dx1 = (x1 - x0) / 2; /* distance to corners from centre */
31 double dy1 = (y1 - y0) / 2;
32 double dx2 = (x2 - x0) / 2;
33 double dy2 = (y2 - y0) / 2;
34
35 if (firstTime) {
36 double a = 0.0;
37 double da = 2.0*3.14159 / 20;
38 for (i=0; i < 20; ++i, a+=da) {
39 sins[i] = sin(a);
40 coss[i] = cos(a);
41 }
42 firstTime = 0;
43 }
44 for(i=0; i < 20; ++i) {
45 double c = coss[i];
46 double s = sins[i];
47 pts[i].x = x + c*dx1 + s*dx2;
48 pts[i].y = y + c*dy1 + s*dy2;
49 }
50 return Polygon(hdc,pts,20);
51 }
52