1、直方图效果图如下
2、main.cpp代码 如下：#include <qapplication.h>#include <qmainwindow.h>#include <qtoolbar.h>#include <qtoolbutton.h>#include <qcombobox.h>#include "barchart.h"class MainWindow: public QMainWindow{public: MainWindow( QWidget * = NULL );private: BarChart *d_chart;};MainWindow::MainWindow( QWidget *parent ): QMainWindow( parent ){ d_chart = new BarChart( this ); setCentralWidget( d_chart ); QToolBar *toolBar = new QToolBar( this ); QComboBox *orientationBox = new QComboBox( toolBar ); orientationBox->addItem( "Vertical" ); orientationBox->addItem( "Horizontal" ); orientationBox->setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed ); QToolButton *btnExport = new QToolButton( toolBar ); btnExport->setText( "Export" ); btnExport->setToolButtonStyle( Qt::ToolButtonTextUnderIcon ); connect( btnExport, SIGNAL( clicked() ), d_chart, SLOT( exportChart() ) ); toolBar->addWidget( orientationBox ); toolBar->addWidget( btnExport ); addToolBar( toolBar ); d_chart->setOrientation( orientationBox->currentIndex() ); connect( orientationBox, SIGNAL( currentIndexChanged( int ) ), d_chart, SLOT( setOrientation( int ) ) );}int main( int argc, char **argv ){ QApplication a( argc, argv ); MainWindow mainWindow; mainWindow.resize( 600, 400 ); mainWindow.show(); return a.exec();}
3、barchart.h文件如下：#ifndef _BAR_CHART_H_#include <qwt_plot.h>#include <qstringlist.h>class DistroChartItem;class BarChart: public QwtPlot{ Q_OBJECTpublic: BarChart( QWidget * = NULL );public Q_SLOTS: void setOrientation( int ); void exportChart();private: void populate(); DistroChartItem *d_barChartItem;//自定义直方图类 QStringList d_distros;//改变方向重置标题用};#endif
4、barchat.cpp代码如下：#include "barchart.h"#include <qwt_plot_renderer.h>#include <qwt_plot_canvas.h>#include <qwt_plot_barchart.h>#include <qwt_column_symbol.h>#include <qwt_plot_layout.h>#include <qwt_legend.h>#include <qwt_scale_draw.h>class DistroScaleDraw: public QwtScaleDraw{public: DistroScaleDraw( Qt::Orientation orientation, const QStringList &labels ): d_labels( labels ) { setTickLength( QwtScaleDiv::MinorTick, 0 ); setTickLength( QwtScaleDiv::MediumTick, 0 ); setTickLength( QwtScaleDiv::MajorTick, 2 ); enableComponent( QwtScaleDraw::Backbone, false ); if ( orientation == Qt::Vertical ) { setLabelRotation( -60.0 ); } else { setLabelRotation( -20.0 ); } setLabelAlignment( Qt::AlignLeft | Qt::AlignVCenter ); } //刻度标签值 virtual QwtText label( double value ) const { QwtText lbl; const int index = qRound( value );//四舍五入 if ( index >= 0 && index <= d_labels.size() ) { lbl = d_labels[ index ]; } return lbl; }private: const QStringList d_labels;};//直方图//QwtPlotBarChart将一系列数据显示为barclass DistroChartItem: public QwtPlotBarChart{public: DistroChartItem(): QwtPlotBarChart( "Page Hits" ) { setLegendMode( QwtPlotBarChart::LegendBarTitles );//显示所有bar各自的标题，而QwtPlotBarChart::LegendChartTitle 显示这个表的标题 setLegendIconSize( QSize( 10, 14 ) ); } //分配颜色和标题给bar，并更新 void addDistro( const QString &distro, const QColor &color ) { d_colors += color; d_distros += distro; itemChanged();//Update the legend of the parent plot. } //自定义每个Bar virtual QwtColumnSymbol *specialSymbol( int index, const QPointF& ) const { QwtColumnSymbol *symbol = new QwtColumnSymbol( QwtColumnSymbol::Box ); symbol->setLineWidth( 1 ); symbol->setFrameStyle( QwtColumnSymbol::Plain );//Raised QColor c( Qt::white ); if ( index >= 0 && index < d_colors.size() ) c = d_colors[ index ]; symbol->setPalette( c ); return symbol; } //自定义每个bar的标题 virtual QwtText barTitle( int sampleIndex ) const { QwtText title; if ( sampleIndex >= 0 && sampleIndex < d_distros.size() ) title = d_distros[ sampleIndex ]; return title; }private: QList<QColor> d_colors; QList<QString> d_distros;};BarChart::BarChart( QWidget *parent ): QwtPlot( parent ){ const struct { const char *distro; const int hits; QColor color; } pageHits[] = { { "Arch", 1114, QColor( "DodgerBlue" ) }, { "Debian", 1373, QColor( "#d70751" ) }, { "Fedora", 1638, QColor( "SteelBlue" ) }, { "Mageia", 1395, QColor( "Indigo" ) }, { "Mint", 3874, QColor( 183, 255, 183 ) }, { "openSuSE", 1532, QColor( 115, 186, 37 ) }, { "Puppy", 1059, QColor( "LightSkyBlue" ) }, { "Ubuntu", 2391, QColor( "FireBrick" ) } }; setAutoFillBackground( true ); setPalette( QColor( "Linen" ) ); //设置画布 QwtPlotCanvas *canvas = new QwtPlotCanvas(); canvas->setLineWidth( 2 ); canvas->setFrameStyle( QFrame::Box | QFrame::Sunken ); canvas->setBorderRadius( 10 ); QPalette canvasPalette( QColor( "Plum" ) ); canvasPalette.setColor( QPalette::Foreground, QColor( "Indigo" ) ); canvas->setPalette( canvasPalette ); setCanvas( canvas ); setTitle( "DistroWatch Page Hit Ranking, April 2012" ); d_barChartItem = new DistroChartItem(); //数据源 QVector< double > samples; for ( uint i = 0; i < sizeof( pageHits ) / sizeof( pageHits[ 0 ] ); i++ ) { d_distros += pageHits[ i ].distro; //给标题赋值 samples += pageHits[ i ].hits;//给数据赋值 d_barChartItem->addDistro( pageHits[ i ].distro, pageHits[ i ].color );//更新颜色和标题 } d_barChartItem->setSamples( samples );//更新数据 d_barChartItem->attach( this ); insertLegend( new QwtLegend() ); setOrientation( 0 ); setAutoReplot( false );}void BarChart::setOrientation( int o ){ const Qt::Orientation orientation = ( o == 0 ) ? Qt::Vertical : Qt::Horizontal; int axis1 = QwtPlot::xBottom; int axis2 = QwtPlot::yLeft; if ( orientation == Qt::Horizontal ) qSwap( axis1, axis2 ); d_barChartItem->setOrientation( orientation );//直方图方向 d_barChartItem->setSpacing( 20 );//spacing 是两个样本之间的距离（两个直方图之间的距离，或者每组直方图之间的距离 d_barChartItem->setMargin( 30);// margin 最外层的直方图与画布的边框矩形之间的距离 setAxisTitle( axis1, "Distros" ); setAxisMaxMinor( axis1, 3);//设置坐标轴小刻度的最大值 setAxisMaxMajor( axis1, 10);//设置坐标轴大刻度的最大值 setAxisScaleDraw( axis1, new DistroScaleDraw( orientation, d_distros ) );//需要重新更新标题 setAxisTitle( axis2, "Hits per day ( HPD )" ); setAxisMaxMinor( axis2, 3 ); QwtScaleDraw *scaleDraw = new QwtScaleDraw(); scaleDraw->setTickLength( QwtScaleDiv::MediumTick, 4 ); setAxisScaleDraw( axis2, scaleDraw ); plotLayout()->setCanvasMargin( 0 ); replot();}void BarChart::exportChart(){ QwtPlotRenderer renderer; renderer.exportTo( this, "distrowatch.pdf" );}
