使用GDI+画仪表表盘

Gdiplus::Bitmap * CSlaveView::GetPumpImage( float fMin,float fMax,float fValue,CString strUnit ) 
{ 
    const float PI=3.141592653; 
    if(fMin>fValue) 
    { 
        fMin=fValue; 
    } 
    if(fValue>fMax) 
    { 
        fMax=fValue; 
    } 
    int nWidth,nHeight; 
    nWidth=nHeight=200; 
    Gdiplus::Rect rect(0,0,nWidth,nHeight); 
    int nTable=5;       //  大格 
    int nScale=5;       //  每小段里面的小格 
    //  每段颜色 
    Gdiplus::Color TableColor[]= 
    { 
        Gdiplus::Color::Green, 
        Gdiplus::Color::Blue, 
        Gdiplus::Color::Cyan, 
        Gdiplus::Color::Yellow, 
        Gdiplus::Color::Red 
    }; 
    //  张开的弧度 
    float fRadian=60; 
    //  同心圆半径 
    int nRadius[]= 
    { 
        200, 
        160, 
        90 
    }; 
    //  圆心 
    Gdiplus::Point ptCenter(nWidth/2,nHeight+20); 
    //  刻度线长度 
    int nLongScal=15; 
    int nShortScal=10; 
    //  背景色 
    Gdiplus::Color bkColor=Gdiplus::Color::SkyBlue; 
    //  刻度字体,大小,颜色 
    Gdiplus::Color ScaleColor=Gdiplus::Color::Blue; 
    Gdiplus::REAL   ScaleSize=10; 
    CString ScaleFont=_T("Times New Roman"); 
 
    Gdiplus::Bitmap *pImage=new Gdiplus::Bitmap(nWidth,nHeight); 
    Graphics *pGraph=Graphics::FromImage(pImage); 
    Gdiplus::StringFormat format; 
    //  消除锯齿 
    format.SetAlignment( StringAlignmentCenter); 
    format.SetLineAlignment(StringAlignmentCenter); 
    pGraph->SetTextRenderingHint(TextRenderingHintAntiAlias); 
    pGraph->Clear(Gdiplus::Color::Transparent); 
    Gdiplus::Color LineColor=Gdiplus::Color::Chocolate; 
    Gdiplus::Pen LinePen(LineColor,1); 
    //  画三段弧 
    rect=Gdiplus::Rect(ptCenter.X-nRadius[0],ptCenter.Y-nRadius[0],2*nRadius[0],2*nRadius[0]); 
    pGraph->DrawArc(&LinePen,rect,180+(90-fRadian/2),fRadian); 
    rect=Gdiplus::Rect(ptCenter.X-nRadius[1],ptCenter.Y-nRadius[1],2*nRadius[1],2*nRadius[1]); 
    pGraph->DrawArc(&LinePen,rect,180+(90-fRadian/2),fRadian); 
    rect=Gdiplus::Rect(ptCenter.X-nRadius[2],ptCenter.Y-nRadius[2],2*nRadius[2],2*nRadius[2]); 
    pGraph->DrawArc(&LinePen,rect,180+(90-fRadian/2),fRadian); 
     
    //  标刻度 
     
    //  分段 
    for(int i=0;i<=nTable*nScale;i++) 
    { 
        Gdiplus::Point p1,p0; 
        double f0=((180-fRadian)/2+fRadian/(nTable*nScale)*i)/180*PI; 
        p1.X=ptCenter.X+nRadius[1]*cos(f0); 
        p1.Y=ptCenter.Y-nRadius[1]*sin(f0); 
        if(i%nTable==0) 
        { 
 
            { 
                p0.X=ptCenter.X+(nRadius[1]+nLongScal)*cos(f0); 
                p0.Y=ptCenter.Y-(nRadius[1]+nLongScal)*sin(f0); 
 
                CString str; 
                str.Format(_T("%.0f"),fMax-(fMax-fMin)/(nTable*nScale)*i); 
                //  获取文本所占的大小 www..2cto.com  
                CSize size=CGraphCurveView::GetOutPutTextSize(pGraph,str,ScaleFont,ScaleSize); 
                Gdiplus::RectF textrc; 
                textrc.X=p0.X-size.cx/2; 
                textrc.Y=p0.Y-size.cy; 
                textrc.Width=size.cx; 
                textrc.Height=size.cy; 
                pGraph->DrawString( 
                    str, 
                    -1, 
                    &Gdiplus::Font(ScaleFont,ScaleSize), 
                    textrc, 
                    &format, 
                    &Gdiplus::SolidBrush(ScaleColor) 
                    ); 
                Gdiplus::Point p2,p3; 
                int nGap=5; 
                p3.X=ptCenter.X+(nRadius[0]+0)*cos(f0); 
                p3.Y=ptCenter.Y-(nRadius[0]+0)*sin(f0); 
                p2.X=ptCenter.X+(nRadius[0]-nGap)*cos(f0); 
                p2.Y=ptCenter.Y-(nRadius[0]-nGap)*sin(f0); 
                pGraph->DrawLine(&LinePen,p2,p3); 
            } 
             
        } 
        else 
        { 
            p0.X=ptCenter.X+(nRadius[1]+nShortScal)*cos(f0); 
            p0.Y=ptCenter.Y-(nRadius[1]+nShortScal)*sin(f0); 
        } 
 
        pGraph->DrawLine(&LinePen,p0,p1); 
    } 
 
    CString strDataFont=_T("Times New Roman"); 
    int DataSize=15; 
    Gdiplus::Color DataColor=Gdiplus::Color::Red; 
 
    //  单位 
    Gdiplus::RectF UnitRc; 
    CSize size=CGraphCurveView::GetOutPutTextSize(pGraph,strUnit,strDataFont,DataSize); 
    UnitRc.X=ptCenter.X-size.cx/2; 
    UnitRc.Y=ptCenter.Y-(nRadius[0]-nRadius[1]+nRadius[2]+size.cy/2); 
    UnitRc.Width=size.cx; 
    UnitRc.Height=size.cy; 
    pGraph->DrawString( 
        strUnit, 
        -1, 
        &Gdiplus::Font(strDataFont,DataSize), 
        UnitRc, 
        &format, 
        &Gdiplus::SolidBrush(DataColor) 
        ); 
 
    //  数据 
    CString strData; 
    strData.Format(_T("%.0f"),fValue); 
    size=CGraphCurveView::GetOutPutTextSize(pGraph,strData,strDataFont,DataSize); 
    Gdiplus::RectF DataRc; 
    DataRc.X=ptCenter.X-size.cx/2; 
    DataRc.Y=ptCenter.Y-(nRadius[2]-nLongScal); 
    DataRc.Width=size.cx; 
    DataRc.Height=size.cy; 
    pGraph->DrawString( 
        strData, 
        -1, 
        &Gdiplus::Font(strDataFont,DataSize), 
        DataRc, 
        &format, 
        &Gdiplus::SolidBrush(DataColor) 
        ); 
 
    //  画指针 
    Gdiplus::Pen PointPen(Gdiplus::Color::Green,2); 
    Gdiplus::Point p0,p1; 
    double f0=((180-fRadian)/2+fRadian/(fMax-fMin)*(-fValue+fMax))/180*PI; 
    p0.X=ptCenter.X+(nRadius[2]*cos(f0)); 
    p0.Y=ptCenter.Y-(nRadius[2]*sin(f0)); 
    p1.X=ptCenter.X+((nRadius[1]+nShortScal/2)*cos(f0)); 
    p1.Y=ptCenter.Y-((nRadius[1]+nShortScal/2)*sin(f0)); 
    pGraph->DrawLine(&PointPen,p0,p1); 
 
    delete pGraph; 
    return pImage; 
} 
效果:







作者  rattlerattle