用GDI+旋转多边形来绘制一个时钟摸拟小程序

TCHAR m_dayStr[4];　　　　// 日期

    TCHAR m_weekStr[4];　　// 星期

    Gdiplus::Font*m_pFont;　　// 字体

    Gdiplus::StringFormat m_strFormat;　　// 格式化字符串

    Gdiplus::Pen*m_pPen;　　　　　　// 画笔

    Gdiplus::SolidBrush*m_pBrush;　　// 画刷

    Gdiplus::RectF m_dayRect;　　　　　　// 日期矩形

    Gdiplus::RectF m_weekRect;　　　　　　// 星期矩形

    Gdiplus::PointF m_orgPointF;//圆点坐标
    float m_rColok;    //圆半径

Gdiplus::PointF hourPts[4];　　//时针多边形数组
Gdiplus::PointF mimPts[4];　　　　//分针多边形数组
Gdiplus::PointF scrPts[2];　　　　//秒针数组

//获得系统时间
SYSTEMTIME sysTime;

GetLocalTime(&sysTime);//格式化日期和星期字符串
_stprintf_s(m_dayStr,TEXT("%02d"),sysTime.wDay);



TCHAR weekStrs[7][4]={L"日",L"一",L"二",L"三",L"四",L"五",L"六"};

_stprintf_s(m_weekStr,TEXT("%s"),weekStrs[sysTime.wDayOfWeek]);//启动时间计时器
SetTimer(m_hWnd,11,1000,NULL);

float cx=LOWORD(lParam);float cy=HIWORD(lParam);//计算圆点
    m_orgPointF.X=cx/2;

    m_orgPointF.Y=cy/2;//计算半径
    m_rColok=min(cx,cy)/2;

    m_rColok-=10;float r=m_rColok;//秒针数组赋值
    scrPts[0].X=0;

    scrPts[0].Y=-r*9/10;

    scrPts[1].X=0;

    scrPts[1].Y=r*2/10;//分针多边形坐标数组
    mimPts[0].X=(float)(-r*0.7 / 10);

    mimPts[0].Y=0;

    mimPts[1].X=0;

    mimPts[1].Y=-r * 8/ 10;

    mimPts[2].X=(float)(r*0.7 / 10);

    mimPts[2].Y=0;

    mimPts[3].X=0;

    mimPts[3].Y=r * 2/ 10;//时针多边形数组
    hourPts[0].X=-r / 10;

    hourPts[0].Y=0;

    hourPts[1].X=0;

    hourPts[1].Y=-r * 6/ 10;

    hourPts[2].X=r / 10;

    hourPts[2].Y=0;

    hourPts[3].X=0;

    hourPts[3].Y=r * 2/ 10;//日期矩形
    m_dayRect.X=r-16;

    m_dayRect.Y=-10;

    m_dayRect.Width=20;

    m_dayRect.Height=20;//日期矩形
    m_weekRect.X=r-36;

    m_weekRect.Y=-10;

    m_weekRect.Width=20;

    m_weekRect.Height=20;    

// 旋转多边形,并绘制
// (绘制对象,多边形顶点坐标数组,顶点个数,旋转角度)
void RotatePolygon(Gdiplus::Graphics* graphics, Gdiplus::PointF* points, int numPoints, floatangle) {//创建旋转矩阵
Gdiplus::Matrix matrix;

    matrix.Rotate(angle);//旋转多边形的每个点
    Gdiplus::PointF* rotatedPoints = newGdiplus::PointF[numPoints];for (int i = 0; i < numPoints; i++) {

        Gdiplus::PointF point=points[i];

        matrix.TransformPoints(&point, 1);

        rotatedPoints[i]=point;

    }



    Gdiplus::Pen pen(Color(255,0,0,0),(numPoints==2) ? 2.0f:1.0f);//绘制旋转后的多边形
    graphics->DrawPolygon(&pen, rotatedPoints, numPoints);
　　
　　
　　// 用线性渐变画刷填充多边形

    graphics->FillPolygon(&Gdiplus::LinearGradientBrush(rotatedPoints[0],rotatedPoints[2],

        Color(255,0,0,255),Color(255,255,255,0)),rotatedPoints,numPoints);delete[] rotatedPoints;

}

voidMyMainWnd::OnPaint(){



    PAINTSTRUCT ps;

    HDC hdc=BeginPaint(m_hWnd,&ps);//创建内存dc,创建内存位图,并将内存位图选入内存dc中
    HDC hmdc=CreateCompatibleDC(hdc);;

    HBITMAP hBitmap=CreateCompatibleBitmap(hdc,ps.rcPaint.right,ps.rcPaint.bottom);

    HGDIOBJ hOldMap=SelectObject(hmdc,hBitmap);//创建在内存dc中绘图对象
Gdiplus::Graphics g(hmdc);

    g.SetSmoothingMode(SmoothingModeAntiAlias);//设置抗锯齿模式//用指定颜色填充整个内存位图
    m_pBrush->SetColor(Color(255,128,128,129));

    g.FillRectangle(m_pBrush,0,0,ps.rcPaint.right,ps.rcPaint.bottom);//设置新的坐标系原点为表盘中心点
Gdiplus::Matrix transform;

    transform.Translate(m_orgPointF.X, m_orgPointF.Y);

    g.SetTransform(&transform);floatxBegin,yBegin;float rClock=m_rColok; //圆的半径//用指定颜色的画刷,绘制表盘上的刻度
    m_pBrush->SetColor(Color(255,217,222,18));for(int i=0;i<60;i++)

    {

        xBegin= (float)( rClock * sin(2 * PI*i / 60));

        yBegin= (float)(rClock * cos(2 * PI*i / 60));if (i % 5)

        {//填充小圆点表示小刻度
            g.FillEllipse(m_pBrush,xBegin-2,yBegin-2,4.0f,4.0f);

        }else{//填充大圆点表示大刻度
            g.FillEllipse(m_pBrush,xBegin-4,yBegin-4,8.0f,8.0f);

        }

    }//获取系统时间
SYSTEMTIME x;

    GetLocalTime(&x);//绘制显示日期和星期的矩形区域
    m_pPen->SetColor(Color::Black);

    m_pBrush->SetColor(Color::YellowGreen);

    g.DrawRectangle(m_pPen,m_dayRect);

    g.DrawRectangle(m_pPen,m_weekRect);

    g.FillRectangle(m_pBrush,m_dayRect);

    g.FillRectangle(m_pBrush,m_weekRect);//绘制日期和星期的字符串文本
    m_pBrush->SetColor(Color::Black);

    g.DrawString(m_dayStr,-1,m_pFont,m_dayRect,&m_strFormat,m_pBrush);

    g.DrawString(m_weekStr,-1,m_pFont,PointF(m_weekRect.X+1,m_weekRect.Y+4),m_pBrush);//绘制时针
    float tem=(float)((float)x.wMinute/60);float fHour=x.wHour+tem;float sita=float(fHour*30);

    RotatePolygon(&g,hourPts,4,(float)sita); //计算时针旋转角度并绘制//绘制分针
    sita=float(x.wMinute*6);

    RotatePolygon(&g,mimPts,4,(float)sita);//绘制秒针
    sita = float(x.wSecond*6);

    RotatePolygon(&g,scrPts,2,sita);//绘制圆心
    m_pBrush->SetColor(Color(255,0,0,255));

    g.FillEllipse(m_pBrush,-6,-6,12,12);//将内存dc中绘制的图片复制到当前dc中
    BitBlt(hdc,0,0,(int)ps.rcPaint.right,(int)ps.rcPaint.bottom,hmdc,0,0,SRCCOPY);//释放内存位图,内存dc
SelectObject(hmdc,hOldMap);

    DeleteObject(hBitmap);

    DeleteObject(hmdc);



    EndPaint(m_hWnd,&ps);

}