hEntity GraphicsWindow::SplitEntity(hEntity he, Vector pinter) {
Entity *e = SK.GetEntity(he);
int entityType = e->type;
hEntity ret;
if(e->IsCircle()) {
ret = SplitCircle(he, pinter);
} else if(e->type == Entity::LINE_SEGMENT) {
ret = SplitLine(he, pinter);
} else if(e->type == Entity::CUBIC || e->type == Entity::CUBIC_PERIODIC) {
ret = SplitCubic(he, pinter);
} else {
Error("Couldn't split this entity; lines, circles, or cubics only.");
return Entity::NO_ENTITY;
}
// Finally, delete the request that generated the original entity.
int reqType = EntReqTable::GetRequestForEntity(entityType);
SK.request.ClearTags();
for(int i = 0; i < SK.request.n; i++) {
Request *r = &(SK.request.elem[i]);
if(r->group.v != activeGroup.v) continue;
if(r->type != reqType) continue;
// If the user wants to keep the old entities around, they can just
// mark them construction first.
if(he.v == r->h.entity(0).v && !r->construction) {
r->tag = 1;
break;
}
}
DeleteTaggedRequests();
return ret;
}
/*
*--------------------------------------------------------------------------------
* 函数名 : CreatePos
* 功能 : 计算出轨迹上所有点的集合，保存到列表中去
* 算法 : 由五角星的外部五个顶点和内部五个顶点依次连线，
* 能过 LineDDA 函数得出所有的轨迹点座标
* 前置条件 : 必须已经设定了轨迹起始点座标和终止点座标
* 后置条件 : 在 m_listTrackPoints 列表中保存所有轨迹点的座标
*--------------------------------------------------------------------------------
*/
BOOL CFiveSideTrack::CreatePos()
{
CPoint ptOutVertex[5];
// 五等分圆，得到五个顶点座标
SplitCircle(m_ptTrackStartPoint, m_ptTrackEndPoint, 5, ptOutVertex);
// 将五边形的外部五顶点依次连线用 LineDDA 得到轨迹点
LineDDA(ptOutVertex[0].x, ptOutVertex[0].y, ptOutVertex[1].x, ptOutVertex[1].y, CTrack::AddPosToList, (LPARAM) this);
LineDDA(ptOutVertex[1].x, ptOutVertex[1].y, ptOutVertex[2].x, ptOutVertex[2].y, CTrack::AddPosToList, (LPARAM) this);
LineDDA(ptOutVertex[2].x, ptOutVertex[2].y, ptOutVertex[3].x, ptOutVertex[3].y, CTrack::AddPosToList, (LPARAM) this);
LineDDA(ptOutVertex[3].x, ptOutVertex[3].y, ptOutVertex[4].x, ptOutVertex[4].y, CTrack::AddPosToList, (LPARAM) this);
LineDDA(ptOutVertex[4].x, ptOutVertex[4].y, ptOutVertex[0].x, ptOutVertex[0].y, CTrack::AddPosToList, (LPARAM) this);
return TRUE;
}
/*
*--------------------------------------------------------------------------------
* 函数名 : Draw
* 功能 : 画出椭圆轨迹
* 参数 :
* CPoint& ptStart - 椭圆外围矩形左上角座标
* CPoint& ptEnd - 椭圆外围矩形右下角座标
* 算法 : 五等分圆得到五个顶点，再由此五点的交叉连线得到五个内部顶点
*--------------------------------------------------------------------------------
*/
void CFiveSideTrack::Draw(const CPoint &ptStart, const CPoint &ptEnd) const
{
HDC hDC = m_hDC;
if (ptStart.x == ptEnd.x && ptStart.y == ptEnd.y)
{
// 起点和终点相同，就画一个点
SetPixel(hDC, ptStart.x, ptEnd.y, TRACK_PEN_COLOR);
return;
}
CPoint ptOutVertex[5];
// 五等分圆，得到五个顶点座标
SplitCircle(ptStart, ptEnd, 5, ptOutVertex);
// 画五边形
MoveToEx(hDC, ptOutVertex[0].x, ptOutVertex[0].y, NULL);
LineTo(hDC, ptOutVertex[1].x, ptOutVertex[1].y);
LineTo(hDC, ptOutVertex[2].x, ptOutVertex[2].y);
LineTo(hDC, ptOutVertex[3].x, ptOutVertex[3].y);
LineTo(hDC, ptOutVertex[4].x, ptOutVertex[4].y);
LineTo(hDC, ptOutVertex[0].x, ptOutVertex[0].y);
}
