基于MFC的多边形裁剪算法的实现

2024-06-29 23:45| 来源: 网络整理| 查看: 265

基于 M F C MFC MFC的多边形裁剪算法的实现一、新建 M F C MFC MFC项目

此处就不再赘述，没有 M F C MFC MFC基础的可以先看第一个 M F C MFC MFC程序。设置项目名为 P o l y g o n C l i p p i n g PolygonClipping PolygonClipping。【注】：以下没有特殊说明的，均在 P o l y g o n C l i p p i n g V i e w . c p p PolygonClippingView.cpp PolygonClippingView.cpp文件下编程。

二、宏定义设置

在适当位置设置宏。

#define LEFT 1 #define RIGHT 2 #define BOTTOM 4 #define TOP 8 #define XL 100 #define XR 300 #define YT 150 #define YB 300 三、全局变量初始化

在适当位置设置全局变量。

const UINT N = 8; CPoint pt[N], pts[N], ptse[N], p[N], ptset1[N]; int flag=0; 三、窗口初始化 void CPolygonClippingView::OnDraw(CDC* pDC) { CPolygonClippingDoc* pDoc = GetDocument(); ASSERT_VALID(pDoc); if (!pDoc) return; // TODO: 在此处为本机数据添加绘制代码 CPen newpen(PS_SOLID, 1, RGB(255, 0, 0)); CPen *old = pDC->SelectObject(&newpen); pDC->Rectangle(CRect(XL, YT, XR, YB)); ptset1[0] = CPoint(20, 150); ptset1[1] = CPoint(120, 110); ptset1[2] = CPoint(250, 150); ptset1[3] = CPoint(200, 230); ptset1[4] = CPoint(20, 150); pDC->TextOutW(0, 50, L"双击鼠标左键 , 出现要剪切的多边形 "); pDC->SelectObject(old); } 四、多边形初始化

类向导添加消息中的 W M _ L B U T T O N D B L C L K WM\_LBUTTONDBLCLK WM_LBUTTONDBLCLK处理函数。

void CPolygonClippingView::OnLButtonDblClk(UINT nFlags, CPoint point) { // TODO: 在此添加消息处理程序代码和/或调用默认值 CDC* pDC = GetDC(); CPen newpen(PS_SOLID, 1, RGB(0, 0, 0)); CPen *old = pDC->SelectObject(&newpen); flag = 1; pDC->MoveTo(ptset1[0]); for (int i = 1; i LineTo(ptset1[i]); CView::OnLButtonDblClk(nFlags, point); } 五、多边形裁剪算法实现

设置 I D ID ID为 I D _ C l i p p o l y g o n ID\_Clippolygon ID_Clippolygon，添加事件处理程序。

void CPolygonClippingView::OnClippolygon() { // TODO: 在此添加命令处理程序代码 CDC* pDC = GetDC(); CPen newpen(PS_SOLID, 1, RGB(0, 0, 0)); CPen *old = pDC->SelectObject(&newpen); if (flag != 1) { MessageBox(L"请先双击鼠标左键", L"警告！"); } else { int i, k; int code1, code2; int M = 5; RedrawWindow(); k = 0; for (i = 0; i pt[k].x = XL; pt[k].y = ptset1[i].y + (ptset1[i + 1].y - ptset1[i].y)*(XL - ptset1[i].x) / (ptset1[i + 1].x - ptset1[i].x); pt[k + 1].x = ptset1[i + 1].x; pt[k + 1].y = ptset1[i + 1].y; k = k + 2; } if (code1 == 0 && code2 == 0) { if (k == 0) { pt[k].x = ptset1[i].x; pt[k].y = ptset1[i].y; pt[k + 1].x = ptset1[i + 1].x; pt[k + 1].y = ptset1[i + 1].y; k = k + 2; } else { pt[k].x = ptset1[i + 1].x; pt[k].y = ptset1[i + 1].y; k = k + 1; } } if (code1 == 0 && code2 != 0) { pt[k].x = XL; pt[k].y = ptset1[i].y + (ptset1[i + 1].y - ptset1[i].y)*(XL - ptset1[i].x) / (ptset1[i + 1].x - ptset1[i].x); k++; } } pt[k].x = pt[0].x; pt[k].y = pt[0].y; M = k + 1; k = 0; for (i = 0; i if (k == 0) { pts[k].x = pt[i].x; pts[k].y = pt[i].y; pts[k + 1].x = pt[i + 1].x; pts[k + 1].y = pt[i + 1].y; k = k + 2; } else { pts[k].x = pt[i + 1].x; pts[k].y = pt[i + 1].y; k++; } } if (code1 != 0 && code2 == 0) { pts[k].x = XR; pts[k].y = pt[i].y + (pt[i + 1].y - pt[i].y)*(XR - pt[i].x) / (pt[i + 1].x - pt[i].x); pts[k + 1].x = pt[i + 1].x; pts[k + 1].y = pt[i + 1].y; k = k + 2; } } if (code1 == 0 && code2 != 0) { pts[k].x = XR; pts[k].y = pt[i].y + (pt[i + 1].y - pt[i].y)*(XR - pt[i].x) / (pt[i + 1].x - pt[i].x); k = k + 1; } pts[k] = pts[0]; M = k + 1; k = 0; for (i = 0; i if (k == 0) { ptse[k].x = pts[i].x; ptse[k].y = pts[i].y; ptse[k + 1].x = pts[i + 1].x; ptse[k + 1].y = pts[i + 1].y; k = k + 2; } else { ptse[k].x = pts[i + 1].x; ptse[k].y = pts[i + 1].y; k = k + 1; } } if (code1 != 0 && code2 == 0) { ptse[k].y = YB; ptse[k].x = pts[i].x + (pts[i + 1].x - pts[i].x)*(YB - pts[i].y) / (pts[i + 1].y - pts[i + 1].y); ptse[k + 1].x = pts[i + 1].x; ptse[k + 1].y = pts[i + 1].y; k = k + 2; } } if (code1 == 0 && code2 != 0) { ptse[k].y = YB; ptse[k].x = pts[i].x + (pts[i + 1].x - pts[i].x)*(YB - pts[i].y) / (pts[i + 1].y - pts[i + 1].y); k = k + 1; } ptse[k] = ptse[0]; M = k + 1; k = 0; for (i = 0; i p[k].y = YT; p[k].x = ptse[i].x + (ptse[i + 1].x - ptse[i].x)*(YT - ptse[i].y) / (ptse[i + 1].y - ptse[i].y); p[k + 1].x = ptse[i + 1].x; p[k + 1].y = ptse[i + 1].y; k = k + 2; } if (code1 == 0 && code2 == 0) { if (k == 0) { p[k].x = ptse[i].x; p[k].y = ptse[i].y; p[k + 1].x = ptse[i + 1].x; p[k + 1].y = ptse[i + 1].y; k = k + 2; } else { p[k].x = ptse[i + 1].x; p[k].y = ptse[i + 1].y; k = k + 1; } } if (code1 == 0 && code2 != 0) { p[k].y = YT; p[k].x = ptse[i].x + (ptse[i + 1].x - ptse[i].x)*(YT - ptse[i].y) / (ptse[i + 1].y - ptse[i].y); k++; } } p[k] = p[0]; M = k + 1; pDC->MoveTo(p[0]); for (int j = 1; j

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