目盛の調整 :Qwt

標準の場合

	#include "mainwindow.h"
	#include "ui_mainwindow.h"
	#include <qwt_plot_curve.h>
	#include <qwt_plot_grid.h>
	#include <qwt_legend.h>
	MainWindow::MainWindow(QWidget *parent) :
	QwtPlot(parent)
	{
	setTitle( "Sin Curve" );//グラフのタイトル
	//グラフの線
	QwtPlotCurve *curve = new QwtPlotCurve();
	curve->attach(this);
	//setAxisScale( QwtPlot::xBottom, 0, 360 );//X軸　目盛
	// グリッドの設定
	QwtPlotGrid *grid = new QwtPlotGrid();
	//grid->enableXMin(true);//中間縦線の表示
	grid->attach( this );
	setAxisScale(2,0,360,20);//X軸,始点,終点,ステップ
	const int kArraySize = 37;
	double plotX[kArraySize] = {}; // x
	double plotY[kArraySize] = {}; // y
	int i= 0;
	for(int k = 0; k <= 360; k+=10 ){
	double x = k;
	double y = sin(k*M_PI/180);
	qDebug() << i << "::" << k << "::" << x <<"::"<<y;
	plotX[i] = x;
	plotY[i] = y;
	++i;
	}
	curve->setSamples(plotX, plotY, kArraySize);
	resize( 600, 400 );
	}
	MainWindow::~MainWindow()
	{
	delete ui;
	}

view raw mainwindow.cpp hosted with ❤ by GitHub

---

QwtScaleDiv を使って目盛を調整

majorTicks,mediumTicks,minorTicks の設定

	#include "mainwindow.h"
	#include "ui_mainwindow.h"
	#include <qwt_plot_curve.h>
	#include <qwt_plot_grid.h>
	MainWindow::MainWindow(QWidget *parent) :
	QwtPlot(parent)
	{
	setTitle( "Sin Curve" );//グラフのタイトル
	//グラフの線
	QwtPlotCurve *curve = new QwtPlotCurve();
	curve->attach(this);
	// グリッドの設定
	QwtPlotGrid *grid = new QwtPlotGrid();
	//grid->enableXMin(true);//中間縦線の表示
	grid->attach( this );
	QList<double> majorTicks;
	majorTicks << 0 << 90 << 180 << 270 << 360;
	QList<double> mediumTicks;
	mediumTicks << 30 << 60 << 120 << 150 << 210 << 240 << 300 << 330;
	QList<double> minorTicks;
	minorTicks << 10 << 20 << 40 << 50 << 70 << 80
	<< 100 << 110 << 130 << 140 << 160 << 170 << 190
	<< 200 << 220 << 230 << 250 << 260 << 280 << 290
	<< 310 << 320 << 340 << 350;
	QwtScaleDiv div( 0, 360 );
	div.setTicks(QwtScaleDiv::MajorTick, majorTicks);
	div.setTicks(QwtScaleDiv::MediumTick, mediumTicks);
	div.setTicks(QwtScaleDiv::MinorTick, minorTicks);
	setAxisScaleDiv(QwtPlot::xBottom, div);
	const int kArraySize = 37;
	double plotX[kArraySize] = {}; // x
	double plotY[kArraySize] = {}; // y
	int i= 0;
	for(int k = 0; k <= 360; k+=10 ){
	double x = k;
	double y = sin(k*M_PI/180);
	qDebug() << i << "::" << k << "::" << x <<"::"<<y;
	plotX[i] = x;
	plotY[i] = y;
	++i;
	}
	curve->setSamples(plotX, plotY, kArraySize);
	resize( 600, 400 );
	}
	MainWindow::~MainWindow()
	{
	delete ui;
	}

view raw mainwindow2.cpp hosted with ❤ by GitHub

---

QwtScaleDraw を使って目盛を調整
目盛の文字の色を変更

	#ifndef MYQWTSCALEDRAW_H
	#define MYQWTSCALEDRAW_H
	#include <qwt_scale_draw.h>
	#include <QColor>
	class MyQwtScaleDraw : public QwtScaleDraw
	{
	public:
	MyQwtScaleDraw();
	virtual QwtText label( double value ) const
	{
	qDebug() << value ;
	QwtText scaleLabel = QwtText (QString::number (value));
	scaleLabel.setColor(QColor( "blue" ));
	return scaleLabel;
	}
	private:
	};
	#endif // MYQWTSCALEDRAW_H

view raw myqwtscaledraw.h hosted with ❤ by GitHub

QwtScaleDraw　を継承したクラスを作成して呼び出す。
setAxisScaleDraw( QwtPlot::xBottom, new MyQwtScaleDraw() );

---

MediumTick の表示

	#ifndef MYQWTSCALEDRAW_H
	#define MYQWTSCALEDRAW_H
	#include <qwt_scale_draw.h>
	class MyQwtScaleDraw : public QwtScaleDraw
	{
	public:
	MyQwtScaleDraw();
	void draw(QPainter *painter, const QPalette& palette) const
	{
	QwtScaleDraw::draw(painter, palette);
	if ( hasComponent(QwtAbstractScaleDraw::Labels) )
	{
	//MediumTick の表示
	const QList<double> &mediumTicks = scaleDiv().ticks(QwtScaleDiv::MediumTick);
	for (int i = 0; i < (int)mediumTicks.count(); i++)
	{
	const double v = mediumTicks[i];
	//qDebug() << v;
	if ( scaleDiv().contains(v) )
	drawLabel(painter, mediumTicks[i]);
	}
	}
	}
	};
	#endif // MYQWTSCALEDRAW_H

view raw myqwtscaledraw2.h hosted with ❤ by GitHub

---

目盛りの非表示
plot->enableAxis(QwtPlot::xBottom, false);

目盛りの最大値の取得

plot->setAutoReplot(true);

plot->axisScaleDiv(QwtPlot::xBottom).upperBound();

plot->axisScaleDiv(QwtPlot::xBottom).interval().maxValue();