Chapter 8: Preparing for Battle

目次

1. ソースコード
2. 解説
3. コンパイル・動作確認
4. いじくりまわす
5. 付録：lcdrange.h
6. 付録：lcdrange.cpp
7. 付録：cannon.h
8. 付録：cannon.cpp
9. 付録：main.cpp

ソースコード

解説

        void setRange( int minVal, int maxVal );

    void LCDRange::setRange( int minVal, int maxVal )
    {
        if ( minVal < 0 || maxVal > 99 || minVal > maxVal ) {
          qWarning( "LCDRange::setRange(%d,%d)\n"
                   "\tRange must be 0..99\n"
                   "\tand minVal must not be greater than maxVal",
                   minVal, maxVal );
          return;
        }
        slider->setRange( minVal, maxVal );
    }

    class CannonField : public QWidget
    {
        Q_OBJECT
    public:
        CannonField( QWidget *parent=0, const char *name=0 );

        int angle() const { return ang; }
        QSizePolicy sizePolicy() const;

    public slots:
        void setAngle( int degrees );

    signals:
        void angleChanged( int );

    protected:
        void paintEvent( QPaintEvent * );

    CannonField::CannonField( QWidget *parent, const char *name )
            : QWidget( parent, name )
    {

        ang = 45;
        setPalette( QPalette( QColor( 250, 250, 200) ) );
    }

    void CannonField::setAngle( int degrees )
    {
        if ( degrees < 5 )
            degrees = 5;
        if ( degrees > 70 )
            degrees = 70;
        if ( ang == degrees )
            return;
        ang = degrees;
        repaint();
        emit angleChanged( ang );
    }

    void CannonField::paintEvent( QPaintEvent * )
    {
        QString s = "Angle = " + QString::number( ang );
        QPainter p( this );
        p.drawText( 200, 200, s );
    }

    #include "cannon.h"

    class MyWidget: public QWidget
    {
    public:
        MyWidget( QWidget *parent=0, const char *name=0 );
    };

        LCDRange *angle = new LCDRange( this, "angle" );

        angle->setRange( 5, 70 );

        CannonField *cannonField
            = new CannonField( this, "cannonField" );

        connect( angle, SIGNAL(valueChanged(int)),
                 cannonField, SLOT(setAngle(int)) );
        connect( cannonField, SIGNAL(angleChanged(int)),
                 angle, SLOT(setValue(int)) );

        QGridLayout *grid = new QGridLayout( this, 2, 2, 10 );
        //2x2, 10 pixel border

        grid->addWidget( quit, 0, 0 );

        grid->addWidget( angle, 1, 0, Qt::AlignTop );

        grid->addWidget( cannonField, 1, 1 );

        grid->setColStretch( 1, 10 );

        angle->setValue( 60 );

        angle->setFocus();

        setFocusProxy( slider );

コンパイル・動作確認

[fenjin@murasame t08]$ ls
cannon.cpp  cannon.h  lcdrange.cpp  lcdrange.h  main.cpp
[fenjin@murasame t08]$ progen -n t08 -o t08.pro
[fenjin@murasame t08]$ tmake -o Makefile t08.pro
[fenjin@murasame t08]$ make
g++ -c -pipe -Wall -W -O2 -DNO_DEBUG -I/usr/lib/qt/include -o cannon.o cannon.cpp
g++ -c -pipe -Wall -W -O2 -DNO_DEBUG -I/usr/lib/qt/include -o lcdrange.o lcdrange.cpp
g++ -c -pipe -Wall -W -O2 -DNO_DEBUG -I/usr/lib/qt/include -o main.o main.cpp
/usr/lib/qt/bin/moc cannon.h -o moc_cannon.cpp
g++ -c -pipe -Wall -W -O2 -DNO_DEBUG -I/usr/lib/qt/include -o moc_cannon.o moc_cannon.cpp
/usr/lib/qt/bin/moc lcdrange.h -o moc_lcdrange.cpp
g++ -c -pipe -Wall -W -O2 -DNO_DEBUG -I/usr/lib/qt/include -o moc_lcdrange.o moc_lcdrange.cpp
g++  -o t08 cannon.o lcdrange.o main.o moc_cannon.o moc_lcdrange.o  -L/usr/lib/qt/lib -L/usr/X11R6/lib -lqt -lXext -lX11 -lm
[fenjin@murasame t08]$ ls
Makefile    cannon.o      lcdrange.o  moc_cannon.cpp    moc_lcdrange.o
cannon.cpp  lcdrange.cpp  main.cpp    moc_cannon.o      t08*
cannon.h    lcdrange.h    main.o      moc_lcdrange.cpp  t08.pro

いじくりまわす

void QWidget::update () [slot]

 Updates the widget unless updates are disabled or the widget is hidden.

 Updating the widget will erase the widget contents and generate an appropriate paint event
for the invalidated region. The paint event is processed after the program has returned to
the main event loop. Calling update() many times in a row will generate a single paint event.

If the widgets sets the WRepaintNoErase flag, update() will not erase its contents.

void QWidget::repaint ( int x, int y, int w, int h, bool erase=TRUE ) [slot]

 Repaints the widget directly by calling paintEvent() directly, unless updates
are disabled or the widgetis hidden.
 Erases the widget area (x,y,w,h) if erase is TRUE.

 If w is negative, it is replaced with width() - x. If h is negative, it is replaced
width height() - y.

 Use repaint if your widget needs to be repainted immediately, for example when
doing some animation. In all other cases, update() is to be preferred. Calling
update() many times in a row will generate a single paint event.

 Warning: If you call repaint() in a function which may itself be called from
paintEvent(), you may see infinite recursion. The update() function never generates recursion.

QGridLayout ( QWidget * parent, int nRows = 1, int nCols = 1, int border=0, int space = -1, const char * name=0 )
QGridLayout ( int nRows = 1, int nCols = 1, int space = -1, const char * name=0 )
QGridLayout ( QLayout * parentLayout, int nRows = 1, int nCols = 1, int space = -1, const char * name=0 )

QGridLayout *grid = new QGridLayout(this, 2, 2, 10);

void QGridLayout::addWidget ( QWidget * w, int row, int col, int alignment = 0 )

cannon.cpp, CannonField::paintEvent()の・・・
修正前：
    QPainter p( this );
    p.drawText( 200, 200, s );

修正後：
    p.save();
    p.rotate(ang);
    p.drawText(100,0,s);
    p.restore();

付録：lcdrange.h

#ifndef LCDRANGE_H
#define LCDRANGE_H

#include <qvbox.h>

class QSlider;

class LCDRange : public QVBox
{
        Q_OBJECT
public:
        LCDRange(QWidget *parent=0, const char *name=0);

        int value() const;

public slots:
        void setValue(int);
        void setRange(int minVal, int maxVal);

signals:
        void valueChanged(int);

private:
        QSlider *slider;
};

#endif //LCDRANGE_H

付録：lcdrange.cpp

#include <qslider.h>
#include <qlcdnumber.h>

#include "lcdrange.h"

LCDRange::LCDRange(QWidget *parent, const char *name)
        : QVBox(parent, name)
{
        QLCDNumber *lcd = new QLCDNumber(2, this, "lcd");
        slider = new QSlider(Horizontal, this, "slider");
        slider->setRange(0,99);
        slider->setValue(0);
        connect(slider, SIGNAL(valueChanged(int)), lcd, SLOT(display(int)));
        connect(slider, SIGNAL(valueChanged(int)), SIGNAL(valueChanged(int)));

        setFocusProxy(slider);
}

int LCDRange::value() const
{
        return slider->value();
}

void LCDRange::setValue(int value)
{
        slider->setValue(value);
}

void LCDRange::setRange(int minVal, int maxVal)
{
        if(minVal < 0 || maxVal > 99 || minVal > maxVal) {
                qWarning("LCDRange::setRange(%d, %d)\n /
                        \t Range must be 0...99.\n /
                        \t and minVal must not greater than maxVal",
                        minVal, maxVal);
                return;
        }
        slider->setRange(minVal, maxVal);
}

付録：cannon.h

#ifndef CANNON_H
#define CANNON_H

#include <qwidget.h>

class CannonField : public QWidget
{
        Q_OBJECT
public:
        CannonField(QWidget *parent=0, const char *name=0);

        int angle() const { return ang; }
        QSizePolicy sizePolicy() const;

public slots:
        void setAngle(int degrees);

signals:
        void angleChanged(int);

protected:
        void paintEvent(QPaintEvent *);

private:
        int ang;
};

#endif //CANNON_H

付録：cannon.cpp

#include "cannon.h"
#include <qpainter.h>

CannonField::CannonField(QWidget *parent,const char *name)
        : QWidget(parent, name)
{
        ang = 45;
        setPalette(QPalette(QColor(250,250,200)));
}

void CannonField::setAngle(int degrees)
{
        if(degrees < 5)
                degrees = 5;
        if(degrees > 70)
                degrees = 70;
        if(ang == degrees)
                return;
        ang = degrees;
        repaint();
        emit angleChanged(ang);
}

void CannonField::paintEvent(QPaintEvent *)
{
        QString s = "Angle = " + QString::number(ang);
        QPainter p(this);
        p.drawText(200,200,s);
}

QSizePolicy CannonField::sizePolicy() const
{
        return QSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
}

付録：main.cpp

#include <qapplication.h>
#include <qpushbutton.h>
#include <qlcdnumber.h>
#include <qfont.h>
#include <qlayout.h>

#include "lcdrange.h"
#include "cannon.h"

class MyWidget : public QVBox
{
public:
        MyWidget(QWidget *parent=0, const char *name=0);
};

MyWidget::MyWidget(QWidget *parent, const char *name)
        : QVBox(parent, name)
{
        QPushButton *quit = new QPushButton("&Quit", this, "quit");
        quit->setFont(QFont("Times", 18, QFont::Bold));

        connect(quit, SIGNAL(clicked()), qApp, SLOT(quit()));

        LCDRange *angle = new LCDRange(this, "angle");
        angle->setRange(5,70);

        CannonField *cannonField = new CannonField(this, "cannonField");

        connect(angle, SIGNAL(valueChanged(int)), cannonField, SLOT(setAngle(int)));
        connect(cannonField, SIGNAL(angleChanged(int)), angle, SLOT(setValue(int)));

        QGridLayout *grid = new QGridLayout(this, 2, 2, 10);
        //2x2, 10 pixel border

        grid->addWidget(quit,0,0);
        grid->addWidget(angle, 1, 0, Qt::AlignTop);
        grid->addWidget(cannonField, 1, 1);
        grid->setColStretch(1,10);

        angle->setValue(60);
        angle->setFocus();
}

int main(int argc, char **argv)
{
        QApplication a(argc, argv);

        MyWidget w;
        w.setGeometry(100,100,500,355);
        a.setMainWidget(&w);
        w.show();
        return a.exec();
}