这个demo使用的是新版本的函数，不过目前还没写入文档，当然也可以使用原来的函数替代
#include <graphics.h>
#include <math.h>
void draw_arrow(float sx, float sy,
float ex, float ey,
float r, float len) {
float c = cos(r), s = sin(r);
float dx = sx - ex, dy = sy - ey;
ege_line(sx, sy, ex, ey);
ege_point points[3] = {
ex, ey,
len * ( dx * c + dy * s) + ex,
len * (-dx * s + dy * c) + ey,
len * ( dx * c - dy * s) + ex,
len * ( dx * s + dy * c) + ey
};
ege_fillpoly(3, points);
}
int main( void ) {
initgraph(640, 480);
ege_enable_aa(true);
setcolor(EGEARGB(0xff, 0xff, 0xff, 0xff));
setfillcolor(EGEARGB(0xff, 0xff, 0x0, 0xff));
setlinewidth(2.0f);
draw_arrow(100.0f, 100.0f, 300.0f, 150.0f,
(float)(PI/8), 0.2f);
getch();
return 0;
}