+
+void VFrame::draw_oval(int x1, int y1, int x2, int y2)
+{
+ int w = x2 - x1;
+ int h = y2 - y1;
+ int center_x = (x2 + x1) / 2;
+ int center_y = (y2 + y1) / 2;
+ int x_table[h / 2];
+
+//printf("VFrame::draw_oval %d %d %d %d %d\n", __LINE__, x1, y1, x2, y2);
+
+ for(int i = 0; i < h / 2; i++) {
+// A^2 = -(B^2) + C^2
+ x_table[i] = (int)(sqrt(-SQR(h / 2 - i) + SQR(h / 2)) * w / h);
+//printf("VFrame::draw_oval %d i=%d x=%d\n", __LINE__, i, x_table[i]);
+ }
+
+ for(int i = 0; i < h / 2 - 1; i++) {
+ int x3 = x_table[i];
+ int x4 = x_table[i + 1];
+
+ if(x4 > x3 + 1) {
+ for(int j = x3; j < x4; j++) {
+ draw_pixel(center_x + j, y1 + i);
+ draw_pixel(center_x - j, y1 + i);
+ draw_pixel(center_x + j, y2 - i - 1);
+ draw_pixel(center_x - j, y2 - i - 1);
+ }
+ }
+ else {
+ draw_pixel(center_x + x3, y1 + i);
+ draw_pixel(center_x - x3, y1 + i);
+ draw_pixel(center_x + x3, y2 - i - 1);
+ draw_pixel(center_x - x3, y2 - i - 1);
+ }
+ }
+
+ draw_pixel(center_x, y1);
+ draw_pixel(center_x, y2 - 1);
+ draw_pixel(x1, center_y);
+ draw_pixel(x2 - 1, center_y);
+ draw_pixel(x1, center_y - 1);
+ draw_pixel(x2 - 1, center_y - 1);
+}
+
+