关于继承自CView和CDrawPlaneView（CXXXXXView）类的继承

最新推荐文章于 2022-04-23 14:19:09 发布

原创最新推荐文章于 2022-04-23 14:19:09 发布 · 414 阅读

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本文介绍了一个简单的绘图应用程序实现，重点在于使用不同方法绘制点。文章详细解释了如何通过多种方式实现绘图功能，包括直接在视图类中实现、创建独立的绘图类、以及让绘图类继承自视图类等。

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非常简单的应用场景 DrawPlaneView为绘图类MCF
调用Ondraw（）函数画几个点

enum Option
{   DRAW = 0,
    ERASER,
    PICK,
    DELETEELE,
    BREAK};
struct _currentSettings 
{   Option  currentOption;
    CPoint  mPoint;
    COLORREF RGB;
    int scale; }currentSettings;
// CDrawPlaneView 消息处理程序
void CDrawPlaneView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: 在此添加消息处理程序代码和/或调用默认值
    currentSettings.RGB = RGB(255,0,0);
    currentSettings.mPoint = point;
    currentSettings.currentOption = Option::DRAW;
    currentSettings.scale = 9;

    /*MessageBox(NULL, L"Hello, Windows!", MB_OK);*/
    Invalidate();
    CView::OnLButtonUp(nFlags, point);

}
//方法2
DrawElement temp;
void CDrawPlaneView::OnDraw(CDC* pDC)
{
    CDrawPlaneDoc* pDoc = GetDocument();
    ASSERT_VALID(pDoc);
    if (!pDoc)
        return;
    //方法1
    /*DrawPoint(pDC, currentSettings.mPoint, currentSettings.scale, currentSettings.RGB);*/

    //方法2  3
    temp.DrawPoint(pDC, currentSettings.mPoint, currentSettings.scale, currentSettings.RGB)
};

方法1
直接在DrawPlaneView.cpp 中实现DrawPoint并在头文件上添加定义

void CDrawPlaneView::DrawPoint(CDC *pDc, CPoint point, int scale, COLORREF color)
{
    switch (scale)
    {
    case 1:pDc->SetPixel(point, color); break;
    case 2:pDc->SetPixel(point, color); pDc->SetPixel(point.x + 1, point.y, color); break;
    case 4:pDc->SetPixel(point, color); pDc->SetPixel(point.x + 1, point.y, color);
        pDc->SetPixel(point.x, point.y + 1, color); pDc->SetPixel(point.x + 1, point.y + 1, color); break;
    case 9:

        pDc->SetPixel(point.x - 1, point.y - 1, color);
        pDc->SetPixel(point.x, point.y - 1, color);
        pDc->SetPixel(point.x + 1, point.y - 1, color);

        pDc->SetPixel(point.x - 1, point.y, color);
        pDc->SetPixel(point, color);
        pDc->SetPixel(point.x + 1, point.y, color);

        pDc->SetPixel(point.x - 1, point.y + 1, color);
        pDc->SetPixel(point.x, point.y + 1, color);
        pDc->SetPixel(point.x + 1, point.y + 1, color); break;
    default:
        break;
    }
}

方法2：
新建类

#pragma once
#include "DrawPlaneDoc.h"//这个是必要的，如果没有会报错
//参见[*GetDocument() const编译时错误：缺少“;”(在“*”的前面)](http://blog.youkuaiyun.com/hanjieson/article/details/8194337)#include "DrawPlaneView.h"
class DrawElement :CDrawPlaneView
{
public:
    void DrawPoint(CDC *pDc,CPoint point,int scale, COLORREF color);
    void DrawLine(CDC *pDc, CPoint startpoint, CPoint endpoint,int scale, COLORREF color);
//public:
//  DrawElement();
//  virtual ~DrawElement();
};
然后再实现DrawPoint

第三种方法
不继承任何类

#pragma once
class DrawElement
{
public:
    void DrawPoint(CDC *pDc,CPoint point,int scale, COLORREF color);
    void DrawLine(CDC *pDc, CPoint startpoint, CPoint endpoint,int scale, COLORREF color);
//public:
    DrawElement();
//  virtual ~DrawElement();
};

第四种方法
使DrawElement继承自CView
那么要重写CView的虚函数

class DrawElement :CView
{
public:
    DrawElement();
    virtual ~DrawElement();
    // 重写
public:
    virtual void OnDraw(CDC* pDC);  // 重写以绘制该视图
    virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
protected:
    virtual BOOL OnPreparePrinting(CPrintInfo* pInfo);
    virtual void OnBeginPrinting(CDC* pDC, CPrintInfo* pInfo);
    virtual void OnEndPrinting(CDC* pDC, CPrintInfo* pInfo);

    // 实现
public:
    void DrawPoint(CDC *pDc,CPoint point,int scale, COLORREF color);
    void DrawLine(CDC *pDc, CPoint startpoint, CPoint endpoint,int scale, COLORREF color);

};