VC++开发GIS系统（226）复制区之类的设计及实现

本文介绍GIS系统中复制一个区要素所对应类的设计及实现。首先通过下面的动态图展示复制区的过程。

其实思想和前文《VC++开发GIS系统（225）移动区之菜单响应》类似，只是在鼠标左键松开的时候，调用的添加一个区的函数。

复制区类的定义

在_malaPolygon.h中定义复制区的类，代码如下：

/*
* 复制区
*/
class malapolygondll  CmalaPolysCopy :public CmalaMouseAction
{
public:
  CmalaPolysCopy(CView* mView, malaScreen *pScreen, CString &fileFullPath);
  ~CmalaPolysCopy();
  void LButtonDown(UINT nFlags, malaPoint point);
  void LButtonUp(UINT nFlags, malaPoint point);
  void MouseMove(UINT nFlags, malaPoint point);
private:
  bool mSelected;
  vector<malaPoint> mSPoly;//选择的区
  malaPolyPro mSPolyPro;//选择的区的属性
  CmalaPolysSelect mSelectPoly;

  CString mPath;//文件路径

  bool mIsDraw;
  malaPoint mPointOri;//起点
  vector<malaPoint> mPerPoly;//临时的区
  malaScreen *mScreen;
};

• @ mSelected 是否有区被选中
• @ mSPoly 选中的区的点序列
• @ mSPolyPro 选中区属性
• @ mSelectPoly 选中的区
• @ mPath 区文件路径
• @ mIsDraw 记录是否按下鼠标左键（用于橡皮筋绘图）
• @ mPointOri 移动的起点
• @ mPerPoly 临时区的点序列
• @ mScreen 屏幕坐标

复制区类实现

在_malaPolygon.cpp中实现上述类的定义

/*
* 复制区实现
*/
CmalaPolysCopy::CmalaPolysCopy(CView* mView, malaScreen *pScreen, CString &fileFullPath)
{
  mBaseView = mView;
  mPath = fileFullPath;
  mScreen = pScreen;
  CmalaPolysSelect obj(mView, pScreen, fileFullPath);
  mSelectPoly = obj;
  mSelected = FALSE;
  mIsDraw = FALSE;
}

CmalaPolysCopy::~CmalaPolysCopy()
{
  if (mSPoly.size())
    mSPoly.clear();
}

void CmalaPolysCopy::LButtonDown(UINT nFlags, malaPoint point)
{
  if (!mSelected)
    mSelectPoly.LButtonDown(nFlags, point);
  else
  {
    mIsDraw = TRUE;
    mPointOri = point;
  }
}

void CmalaPolysCopy::LButtonUp(UINT nFlags, malaPoint point)
{
  if (!mSelected)
    mSelectPoly.LButtonUp(nFlags, point);
  else
  {
    CPolyIO lio;
    lio.polyAdd(mPerPoly, mSPolyPro, mPath);
    mBaseView->Invalidate(TRUE);
    mIsDraw = FALSE;
    mSelected = FALSE;
    mSelectPoly.m_Selected = FALSE;
    mSPoly.clear();
  }

  mSelected = mSelectPoly.m_Selected;
  if (mSelected)
  {
    this->mSPoly = mSelectPoly.mSPoly;
    this->mSPolyPro = mSelectPoly.mSPolyPro;
    mPerPoly = mSPoly;
  }

}

void CmalaPolysCopy::MouseMove(UINT nFlags, malaPoint point)
{
  if (!mSelected)
    mSelectPoly.MouseMove(nFlags, point);
  else if (mIsDraw)
  {
    malaCDC dc(mBaseView, *mScreen);
    dc.polyDrawAutoX(mPerPoly, mSPolyPro);
    for (size_t i = 0; i < mPerPoly.size(); i++)
    {
      mPerPoly[i].x = mSPoly[i].x + point.x - mPointOri.x;
      mPerPoly[i].y = mSPoly[i].y + point.y - mPointOri.y;
    }
    dc.polyDrawAutoX(mPerPoly, mSPolyPro);
    dc.polyDrawAuto(mSPoly, mSPolyPro);
  }
}

其中 polyAdd 函数参考《VC++开发GIS系统（213）输入区之保存区函数》，polyDrawAutoX 函数参考《VC++开发GIS系统（208）输入区之绘制区的函数(多边形与椭圆)》

详细代码可以参考：GitHub