bool MgLine::_hitTestBox(const Box2d& rect) const
{
if (!__super::_hitTestBox(rect))
return false;
Point2d pts[2] = { _points[0], _points[1] };
return mgClipLine(pts[0], pts[1], rect);
}
bool GiGraphics::drawLine(const GiContext* ctx,
const Point2d& startPt, const Point2d& endPt,
bool modelUnit)
{
if (m_impl->drawRefcnt == 0)
return false;
GiLock lock (&m_impl->drawRefcnt);
if (!DRAW_RECT(m_impl, modelUnit).isIntersect(Box2d(startPt, endPt)))
return false;
Point2d pts[2] = { startPt * S2D(xf(), modelUnit), endPt * S2D(xf(), modelUnit) };
if (!mgClipLine(pts[0], pts[1], m_impl->rectDraw))
return false;
return rawLine(ctx, pts[0].x, pts[0].y, pts[1].x, pts[1].y);
}
static bool DrawEdge(int count, int &i, Point2d* pts, Point2d &ptLast,
const PolylineAux& aux, const Box2d& rectDraw)
{
int n, si, ei;
Point2d pt1, pt2;
pt1 = ptLast;
ptLast = pts[i+1];
pt2 = ptLast;
if (!mgClipLine(pt1, pt2, rectDraw)) // 该边不可见
return false;
si = i; // 收集第一条可见边
ei = i+1;
pts[i] = pt1; // 收集起点
if (pt2 != ptLast) // 如果该边终点不可见
{
pts[i+1] = pt2; // 收集交点
}
else // 否则继续收集后续点
{
i++; // 下一边的起点可见，跳过
for (; i < count - 1; i++) // 依次处理后续可见边
{
pt1 = ptLast;
ptLast = pts[i+1];
pt2 = ptLast;
if (!mgClipLine(pt1, pt2, rectDraw)) // 该边不可见
break;
ei++;
if (pt2 != ptLast) // 该边起点可见，终点不可见
{
pts[i+1] = pt2; // 收集交点
break;
}
}
}
// 显示找到的多条线段
n = ei - si + 1;
if (n > 1)
{
vector<Point2d> pxpoints;
pxpoints.resize(n);
Point2d* pxs = &pxpoints.front();
n = 0;
for (int j = si; j <= ei; j++)
{
// 记下第一个点，其他点如果和上一点不重合则记下，否则跳过
if (j == si || fabs(pt1.x - pts[j].x) > 2
|| fabs(pt1.y - pts[j].y) > 2)
{
pt1 = pts[j];
pxs[n++] = pt1;
}
}
return aux.draw(pxs, n);
}
return false;
}