How I could Tell Qpainter where is his Area of Painting...

[j0rt4g4]

I made a GUI with designer.
I got a QWidget object called "areadibujo" that has and predetermined area.
Now the problem is that I dont know how to tell "QPainter" that his Space is That one.

Which is the way to tell it that?

Could be QPainterPath? how i could implemented ? I got days within this.
Am I doing something wrong? any ideas?

No one?

[j0rt4g4]

Is my question wrong formulated ? :S

[high_flyer]

What it is you want to do?
ANY widget that you can see is painted by QPainter.
If you want to change the way a particular widget is being drawn, you should overload the paintEvent() of that widget.

[j0rt4g4]

I got a image like this:

In the Center of this image there's a widget called "areadibujo",
I want to paint ON this area, but I dont know how to do it.

I want to create a code that read a file data
(%f %f ) insert it on a array
a[i] b[i]

And use the array to do some math, and get the points on areadibujo but I guess I'm confused with parents.

Well here's my code:
main.cpp:

#include <QApplication>
#include "fractal.h"
#include "renderarea.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    fractal *dialog = new fractal;
   //renderarea *dialog= new renderarea;
 
    dialog->show();
    return app.exec();
}

#include <QApplication>
#include "fractal.h"
#include "renderarea.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    fractal *dialog = new fractal;
   //renderarea *dialog= new renderarea;
 
    dialog->show();
    return app.exec();
}

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fractal.h

#ifndef __FRACTAL_H__
#define __FRACTAL_H__
#include "ui_fractals.h"
 
 
class fractal : public QWidget, private Ui::Fractals
{
	Q_OBJECT
 
public:
	fractal(QWidget *parent = 0);
	void updateBrush();
 
public slots:
	void setOpenFileName();
	void QPaintEvent(QPainter *event);
};
 
 
#endif // __FRACTAL_H__

#ifndef __FRACTAL_H__
#define __FRACTAL_H__
#include "ui_fractals.h"


class fractal : public QWidget, private Ui::Fractals
{
	Q_OBJECT

public:
	fractal(QWidget *parent = 0);
	void updateBrush();
	
public slots:
	void setOpenFileName();
	void QPaintEvent(QPainter *event);
};

	
#endif // __FRACTAL_H__

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fractal.cpp

#include <QtGui>
#include <QFile>
#include <QGLWidget>
#include <QtOpenGL>
#include "fractal.h"
 
void tidyFile(QIODevice *inDevice, QIODevice *outDevice)
{
    QTextStream in(inDevice);
    QTextStream out(outDevice);
 
    int endlCount = 0;
    QChar ch;
 
    while (!in.atEnd()) {
        in >> ch;
 
        if (ch == '\n') {
            ++endlCount;
        }
    }
  //  out << endl;
}
 
 
fractal::fractal(QWidget *parent){
	setupUi(this);
	connect( toolButton, SIGNAL( clicked() ), this, SLOT( setOpenFileName() ) );
	connect( boton_aceptar, SIGNAL( clicked() ), this, SLOT( QPaintEvent(QPainter *event) ) );
}
 
 
void fractal::setOpenFileName()
{
	 QFileDialog::Options options;
     options |=QFileDialog::ShowDirsOnly;
 
 
     QString selectedFilter;
     QString fileName = QFileDialog::getOpenFileName(this,
                                 tr("QFileDialog::getOpenFileName()"),
                                 lineEdit->text(),
                                 tr("Todos (*);;Data (*.txt)"),
                                 &selectedFilter,
                                 options);
     if (!fileName.isEmpty())
         lineEdit->setText(fileName);
 
     QFile infile;
     QFile outfile;
     infile.open(stdin, QFile::ReadOnly);
     outfile.open(stdout, QFile::WriteOnly);
     tidyFile(&infile,&outfile);
     QTextStream in(&infile);
     QTextStream out(&outfile);
     int endlCount = 0;
     QChar ch;
     while (!in.atEnd()) {
        in >> ch;
        if (ch == '\n') {
            ++endlCount;
        }
       }
}
 
void fractal::QPaintEvent(QPainter *event){
	QPainter painter(this);
	painter.setRenderHint(QPainter::Antialiasing, true);
	painter.setPen(QPen(Qt::black, 15, Qt::SolidLine, Qt::RoundCap,
                    Qt::MiterJoin));
	painter.setBrush(QBrush(Qt::blue, Qt::DiagCrossPattern));
	painter.drawPie(80, 80, 400, 240, 60 * 16, 270 * 16);
}

#include <QtGui>
#include <QFile>
#include <QGLWidget>
#include <QtOpenGL>
#include "fractal.h"

void tidyFile(QIODevice *inDevice, QIODevice *outDevice)
{
    QTextStream in(inDevice);
    QTextStream out(outDevice);

    int endlCount = 0;
    QChar ch;

    while (!in.atEnd()) {
        in >> ch;

        if (ch == '\n') {
            ++endlCount;
        }
    }
  //  out << endl;
}


fractal::fractal(QWidget *parent){
	setupUi(this);
	connect( toolButton, SIGNAL( clicked() ), this, SLOT( setOpenFileName() ) );
	connect( boton_aceptar, SIGNAL( clicked() ), this, SLOT( QPaintEvent(QPainter *event) ) );
}


void fractal::setOpenFileName()
{
	 QFileDialog::Options options;
     options |=QFileDialog::ShowDirsOnly;
     
        
     QString selectedFilter;
     QString fileName = QFileDialog::getOpenFileName(this,
                                 tr("QFileDialog::getOpenFileName()"),
                                 lineEdit->text(),
                                 tr("Todos (*);;Data (*.txt)"),
                                 &selectedFilter,
                                 options);
     if (!fileName.isEmpty())
         lineEdit->setText(fileName);
     
     QFile infile;
     QFile outfile;
     infile.open(stdin, QFile::ReadOnly);
     outfile.open(stdout, QFile::WriteOnly);
     tidyFile(&infile,&outfile);
     QTextStream in(&infile);
     QTextStream out(&outfile);
     int endlCount = 0;
     QChar ch;
     while (!in.atEnd()) {
        in >> ch;
        if (ch == '\n') {
            ++endlCount;
        }
       }
}

void fractal::QPaintEvent(QPainter *event){
	QPainter painter(this);
	painter.setRenderHint(QPainter::Antialiasing, true);
	painter.setPen(QPen(Qt::black, 15, Qt::SolidLine, Qt::RoundCap,
                    Qt::MiterJoin));
	painter.setBrush(QBrush(Qt::blue, Qt::DiagCrossPattern));
	painter.drawPie(80, 80, 400, 240, 60 * 16, 270 * 16);
}

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I hope I wasn't wasting my time as I hope...

[spirit]

it is wrong

void fractal::QPaintEvent(QPainter *event)

void fractal::QPaintEvent(QPainter *event)

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must be

void fractal::paintEvent(QPaintEvent *event) {
   //draw something
}

void fractal::paintEvent(QPaintEvent *event) {
   //draw something
}

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and then you must draw what you want

[j0rt4g4]

Ok I made Corrections and IT DRAWS (thank you very much)... But It is painting on the BIG Widget (mainwindow) and It is not ON the widget called (areadibujo).

If you want to change the way a particular widget is being drawn, you should overload the paintEvent() of that widget

Could you tell me how I do that in here ?
Thank you very much

[spirit]

is this "areadibujo" independent? if yes then you have to override paintEvent of this widget.

[j0rt4g4]

mmm I guess it is a son of "Fractals"

Isnt it easier make it independient?, T.T because I dont know how to do it independient eighter... (:S what a noobie guy).... I'm trying .

[spirit]

yep. so you can do next: install event filter for this widget and handle paint event and draw what you need, e.g.

Test::Test(QWidget *parent)
	: QMainWindow(parent)
{
	QVBoxLayout *vbl = new QVBoxLayout();
	QWidget *w = new QWidget;
	m_drawer = new QWidget();
	m_drawer->installEventFilter(this);//set event filter
 
	vbl->addWidget(m_drawer);
	vbl->addWidget(new QWidget);
	w->setLayout(vbl);
 
	setCentralWidget(w);
}
 
bool Test::eventFilter(QObject *o, QEvent *e)
{
	if (o == m_drawer && e->type() == QEvent::Paint) {//process paint event of needed widget
		QPainter painter(m_drawer);
		painter.setPen(Qt::blue);
		painter.setFont(QFont("Arial", 30));
		painter.drawText(m_drawer->rect(), Qt::AlignCenter, "Qt");
		return true;
	}
	return QMainWindow::eventFilter(o, e);
}

Test::Test(QWidget *parent)
	: QMainWindow(parent)
{
	QVBoxLayout *vbl = new QVBoxLayout();
	QWidget *w = new QWidget;
	m_drawer = new QWidget();
	m_drawer->installEventFilter(this);//set event filter

	vbl->addWidget(m_drawer);
	vbl->addWidget(new QWidget);
	w->setLayout(vbl);

	setCentralWidget(w);
}

bool Test::eventFilter(QObject *o, QEvent *e)
{
	if (o == m_drawer && e->type() == QEvent::Paint) {//process paint event of needed widget
		QPainter painter(m_drawer);
		painter.setPen(Qt::blue);
		painter.setFont(QFont("Arial", 30));
		painter.drawText(m_drawer->rect(), Qt::AlignCenter, "Qt");
		return true;
	}
	return QMainWindow::eventFilter(o, e);
}

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[j0rt4g4]

Like this?

ui_Fractals.h:

QT_BEGIN_NAMESPACE
 
class Ui_Fractals
{
public:
    QWidget *layoutWidget;
    QHBoxLayout *horizontalLayout_4;
    QVBoxLayout *verticalLayout_2;
    QHBoxLayout *horizontalLayout_3;
    QLabel *label_Archivo;
    QLineEdit *lineEdit;
    QToolButton *toolButton;
    QWidget *areadibujo;
    QVBoxLayout *verticalLayout;
    QHBoxLayout *horizontalLayout;
    QLabel *Iterations;
    QSpinBox *spinbox_ite;
    QSlider *iterator_hslider;
    QSpacerItem *verticalSpacer;
    QHBoxLayout *horizontalLayout_2;
    QPushButton *boton_aceptar;
    QPushButton *boton_salir;
 
    void setupUi(QWidget *Fractals)
    {
    if (Fractals->objectName().isEmpty())
        Fractals->setObjectName(QString::fromUtf8("Fractals"));
    Fractals->resize(605, 408);
    layoutWidget = new QWidget(Fractals);
    layoutWidget->setObjectName(QString::fromUtf8("layoutWidget"));
    layoutWidget->setGeometry(QRect(10, 10, 579, 382));
    horizontalLayout_4 = new QHBoxLayout(layoutWidget);
    horizontalLayout_4->setObjectName(QString::fromUtf8("horizontalLayout_4"));
    horizontalLayout_4->setContentsMargins(0, 0, 0, 0);
    verticalLayout_2 = new QVBoxLayout();
    verticalLayout_2->setObjectName(QString::fromUtf8("verticalLayout_2"));
    horizontalLayout_3 = new QHBoxLayout();
    horizontalLayout_3->setObjectName(QString::fromUtf8("horizontalLayout_3"));
    label_Archivo = new QLabel(layoutWidget);
    label_Archivo->setObjectName(QString::fromUtf8("label_Archivo"));
 
    horizontalLayout_3->addWidget(label_Archivo);
 
    lineEdit = new QLineEdit(layoutWidget);
    lineEdit->setObjectName(QString::fromUtf8("lineEdit"));
    lineEdit->setEnabled(false);
    lineEdit->setMinimumSize(QSize(280, 0));
    lineEdit->setDragEnabled(false);
 
    horizontalLayout_3->addWidget(lineEdit);
 
    toolButton = new QToolButton(layoutWidget);
    toolButton->setObjectName(QString::fromUtf8("toolButton"));
    toolButton->setMinimumSize(QSize(25, 20));
    toolButton->setCheckable(false);
    toolButton->setPopupMode(QToolButton::DelayedPopup);
    toolButton->setArrowType(Qt::NoArrow);
 
    horizontalLayout_3->addWidget(toolButton);
 
 
    verticalLayout_2->addLayout(horizontalLayout_3);
 
    areadibujo = new QWidget(layoutWidget);
    areadibujo->setObjectName(QString::fromUtf8("areadibujo"));
    areadibujo->setMinimumSize(QSize(350, 350));
    areadibujo->setMaximumSize(QSize(500, 500));
    areadibujo->setAutoFillBackground(false);
    areadibujo->installEventFilter(this); ////////////////////////////here!:confused::confused:
 
 
    verticalLayout_2->addWidget(areadibujo);
 
 
    horizontalLayout_4->addLayout(verticalLayout_2);
 
    verticalLayout = new QVBoxLayout();
    verticalLayout->setObjectName(QString::fromUtf8("verticalLayout"));
    horizontalLayout = new QHBoxLayout();
    horizontalLayout->setObjectName(QString::fromUtf8("horizontalLayout"));
    Iterations = new QLabel(layoutWidget);
    Iterations->setObjectName(QString::fromUtf8("Iterations"));
 
    horizontalLayout->addWidget(Iterations);
 
    spinbox_ite = new QSpinBox(layoutWidget);
    spinbox_ite->setObjectName(QString::fromUtf8("spinbox_ite"));
    spinbox_ite->setEnabled(true);
    spinbox_ite->setMinimumSize(QSize(30, 0));
    spinbox_ite->setMinimum(100000);
    spinbox_ite->setMaximum(1000000);
    spinbox_ite->setSingleStep(1000);
    spinbox_ite->setValue(100000);
 
    horizontalLayout->addWidget(spinbox_ite);
 
    iterator_hslider = new QSlider(layoutWidget);
    iterator_hslider->setObjectName(QString::fromUtf8("iterator_hslider"));
    iterator_hslider->setEnabled(true);
    iterator_hslider->setMouseTracking(true);
    iterator_hslider->setMinimum(100000);
    iterator_hslider->setMaximum(1000000);
    iterator_hslider->setSingleStep(1000);
    iterator_hslider->setPageStep(100000);
    iterator_hslider->setValue(100000);
    iterator_hslider->setTracking(true);
    iterator_hslider->setOrientation(Qt::Horizontal);
 
    horizontalLayout->addWidget(iterator_hslider);
 
 
    verticalLayout->addLayout(horizontalLayout);
 
    verticalSpacer = new QSpacerItem(20, 40, QSizePolicy::Minimum, QSizePolicy::Expanding);
 
    verticalLayout->addItem(verticalSpacer);
 
    horizontalLayout_2 = new QHBoxLayout();
    horizontalLayout_2->setObjectName(QString::fromUtf8("horizontalLayout_2"));
    boton_aceptar = new QPushButton(layoutWidget);
    boton_aceptar->setObjectName(QString::fromUtf8("boton_aceptar"));
 
    horizontalLayout_2->addWidget(boton_aceptar);
 
    boton_salir = new QPushButton(layoutWidget);
    boton_salir->setObjectName(QString::fromUtf8("boton_salir"));
 
    horizontalLayout_2->addWidget(boton_salir);
 
 
    verticalLayout->addLayout(horizontalLayout_2);
 
 
    horizontalLayout_4->addLayout(verticalLayout);
 
 
    retranslateUi(Fractals);
    QObject::connect(boton_salir, SIGNAL(clicked()), Fractals, SLOT(close()));
    QObject::connect(spinbox_ite, SIGNAL(valueChanged(int)), iterator_hslider, SLOT(setValue(int)));
    QObject::connect(iterator_hslider, SIGNAL(valueChanged(int)), spinbox_ite, SLOT(setValue(int)));
 
    QMetaObject::connectSlotsByName(Fractals);
    } // setupUi
 
    void retranslateUi(QWidget *Fractals)
    {
    Fractals->setWindowTitle(QApplication::translate("Fractals", "Fractals", 0, QApplication::UnicodeUTF8));
    label_Archivo->setText(QApplication::translate("Fractals", "Archivo:", 0, QApplication::UnicodeUTF8));
    toolButton->setText(QApplication::translate("Fractals", "...", 0, QApplication::UnicodeUTF8));
    Iterations->setText(QApplication::translate("Fractals", "Iterations", 0, QApplication::UnicodeUTF8));
    boton_aceptar->setText(QApplication::translate("Fractals", "&Aceptar", 0, QApplication::UnicodeUTF8));
    boton_salir->setText(QApplication::translate("Fractals", "&Salir", 0, QApplication::UnicodeUTF8));
    Q_UNUSED(Fractals);
    } // retranslateUi
 
};
 
namespace Ui {
    class Fractals: public Ui_Fractals {};
} // namespace Ui
 
QT_END_NAMESPACE
 
 
bool areadibujo::eventFilter(QObject *o, QEvent *e) //////////and here:confused::confused:
{
	if(o == areadibujo && e->type() == QEvent::Paint){
		QPainter painter(areadibujo);
		painter.setPen(Qt::blue);
		painter.setFont(QFont("Arial",30));
		painter.drawText(areadibujo->rect(), Qt::AlignCenter,"Probando");
		return true;
	}
	return Ui_Fractals::eventFilter(o,e);
}
 
#endif // UI_FRACTALS_H

QT_BEGIN_NAMESPACE

class Ui_Fractals
{
public:
    QWidget *layoutWidget;
    QHBoxLayout *horizontalLayout_4;
    QVBoxLayout *verticalLayout_2;
    QHBoxLayout *horizontalLayout_3;
    QLabel *label_Archivo;
    QLineEdit *lineEdit;
    QToolButton *toolButton;
    QWidget *areadibujo;
    QVBoxLayout *verticalLayout;
    QHBoxLayout *horizontalLayout;
    QLabel *Iterations;
    QSpinBox *spinbox_ite;
    QSlider *iterator_hslider;
    QSpacerItem *verticalSpacer;
    QHBoxLayout *horizontalLayout_2;
    QPushButton *boton_aceptar;
    QPushButton *boton_salir;

    void setupUi(QWidget *Fractals)
    {
    if (Fractals->objectName().isEmpty())
        Fractals->setObjectName(QString::fromUtf8("Fractals"));
    Fractals->resize(605, 408);
    layoutWidget = new QWidget(Fractals);
    layoutWidget->setObjectName(QString::fromUtf8("layoutWidget"));
    layoutWidget->setGeometry(QRect(10, 10, 579, 382));
    horizontalLayout_4 = new QHBoxLayout(layoutWidget);
    horizontalLayout_4->setObjectName(QString::fromUtf8("horizontalLayout_4"));
    horizontalLayout_4->setContentsMargins(0, 0, 0, 0);
    verticalLayout_2 = new QVBoxLayout();
    verticalLayout_2->setObjectName(QString::fromUtf8("verticalLayout_2"));
    horizontalLayout_3 = new QHBoxLayout();
    horizontalLayout_3->setObjectName(QString::fromUtf8("horizontalLayout_3"));
    label_Archivo = new QLabel(layoutWidget);
    label_Archivo->setObjectName(QString::fromUtf8("label_Archivo"));

    horizontalLayout_3->addWidget(label_Archivo);

    lineEdit = new QLineEdit(layoutWidget);
    lineEdit->setObjectName(QString::fromUtf8("lineEdit"));
    lineEdit->setEnabled(false);
    lineEdit->setMinimumSize(QSize(280, 0));
    lineEdit->setDragEnabled(false);

    horizontalLayout_3->addWidget(lineEdit);

    toolButton = new QToolButton(layoutWidget);
    toolButton->setObjectName(QString::fromUtf8("toolButton"));
    toolButton->setMinimumSize(QSize(25, 20));
    toolButton->setCheckable(false);
    toolButton->setPopupMode(QToolButton::DelayedPopup);
    toolButton->setArrowType(Qt::NoArrow);

    horizontalLayout_3->addWidget(toolButton);


    verticalLayout_2->addLayout(horizontalLayout_3);

    areadibujo = new QWidget(layoutWidget);
    areadibujo->setObjectName(QString::fromUtf8("areadibujo"));
    areadibujo->setMinimumSize(QSize(350, 350));
    areadibujo->setMaximumSize(QSize(500, 500));
    areadibujo->setAutoFillBackground(false);
    areadibujo->installEventFilter(this); ////////////////////////////here!:confused::confused:


    verticalLayout_2->addWidget(areadibujo);


    horizontalLayout_4->addLayout(verticalLayout_2);

    verticalLayout = new QVBoxLayout();
    verticalLayout->setObjectName(QString::fromUtf8("verticalLayout"));
    horizontalLayout = new QHBoxLayout();
    horizontalLayout->setObjectName(QString::fromUtf8("horizontalLayout"));
    Iterations = new QLabel(layoutWidget);
    Iterations->setObjectName(QString::fromUtf8("Iterations"));

    horizontalLayout->addWidget(Iterations);

    spinbox_ite = new QSpinBox(layoutWidget);
    spinbox_ite->setObjectName(QString::fromUtf8("spinbox_ite"));
    spinbox_ite->setEnabled(true);
    spinbox_ite->setMinimumSize(QSize(30, 0));
    spinbox_ite->setMinimum(100000);
    spinbox_ite->setMaximum(1000000);
    spinbox_ite->setSingleStep(1000);
    spinbox_ite->setValue(100000);

    horizontalLayout->addWidget(spinbox_ite);

    iterator_hslider = new QSlider(layoutWidget);
    iterator_hslider->setObjectName(QString::fromUtf8("iterator_hslider"));
    iterator_hslider->setEnabled(true);
    iterator_hslider->setMouseTracking(true);
    iterator_hslider->setMinimum(100000);
    iterator_hslider->setMaximum(1000000);
    iterator_hslider->setSingleStep(1000);
    iterator_hslider->setPageStep(100000);
    iterator_hslider->setValue(100000);
    iterator_hslider->setTracking(true);
    iterator_hslider->setOrientation(Qt::Horizontal);

    horizontalLayout->addWidget(iterator_hslider);


    verticalLayout->addLayout(horizontalLayout);

    verticalSpacer = new QSpacerItem(20, 40, QSizePolicy::Minimum, QSizePolicy::Expanding);

    verticalLayout->addItem(verticalSpacer);

    horizontalLayout_2 = new QHBoxLayout();
    horizontalLayout_2->setObjectName(QString::fromUtf8("horizontalLayout_2"));
    boton_aceptar = new QPushButton(layoutWidget);
    boton_aceptar->setObjectName(QString::fromUtf8("boton_aceptar"));

    horizontalLayout_2->addWidget(boton_aceptar);

    boton_salir = new QPushButton(layoutWidget);
    boton_salir->setObjectName(QString::fromUtf8("boton_salir"));

    horizontalLayout_2->addWidget(boton_salir);


    verticalLayout->addLayout(horizontalLayout_2);


    horizontalLayout_4->addLayout(verticalLayout);


    retranslateUi(Fractals);
    QObject::connect(boton_salir, SIGNAL(clicked()), Fractals, SLOT(close()));
    QObject::connect(spinbox_ite, SIGNAL(valueChanged(int)), iterator_hslider, SLOT(setValue(int)));
    QObject::connect(iterator_hslider, SIGNAL(valueChanged(int)), spinbox_ite, SLOT(setValue(int)));

    QMetaObject::connectSlotsByName(Fractals);
    } // setupUi

    void retranslateUi(QWidget *Fractals)
    {
    Fractals->setWindowTitle(QApplication::translate("Fractals", "Fractals", 0, QApplication::UnicodeUTF8));
    label_Archivo->setText(QApplication::translate("Fractals", "Archivo:", 0, QApplication::UnicodeUTF8));
    toolButton->setText(QApplication::translate("Fractals", "...", 0, QApplication::UnicodeUTF8));
    Iterations->setText(QApplication::translate("Fractals", "Iterations", 0, QApplication::UnicodeUTF8));
    boton_aceptar->setText(QApplication::translate("Fractals", "&Aceptar", 0, QApplication::UnicodeUTF8));
    boton_salir->setText(QApplication::translate("Fractals", "&Salir", 0, QApplication::UnicodeUTF8));
    Q_UNUSED(Fractals);
    } // retranslateUi

};

namespace Ui {
    class Fractals: public Ui_Fractals {};
} // namespace Ui

QT_END_NAMESPACE


bool areadibujo::eventFilter(QObject *o, QEvent *e) //////////and here:confused::confused:
{
	if(o == areadibujo && e->type() == QEvent::Paint){
		QPainter painter(areadibujo);
		painter.setPen(Qt::blue);
		painter.setFont(QFont("Arial",30));
		painter.drawText(areadibujo->rect(), Qt::AlignCenter,"Probando");
		return true;
	}
	return Ui_Fractals::eventFilter(o,e);
}

#endif // UI_FRACTALS_H

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[spirit]

no, not in generated h-file. you should install filter in that widget for which you set up ui, i.e.

fractal::fractal(QWidget *parent)
: QWidget(parent)
{
    setupUi(this);
    areadibujo->installEventFilter(this);
    connect( toolButton, SIGNAL( clicked() ), this, SLOT( setOpenFileName() ) );
}

fractal::fractal(QWidget *parent)
: QWidget(parent)
{
    setupUi(this);
    areadibujo->installEventFilter(this);
    connect( toolButton, SIGNAL( clicked() ), this, SLOT( setOpenFileName() ) );
}

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[j0rt4g4]

Welll...... It runs but doesn't show anything...
I did it like this :

main.cpp

#include <QApplication>
#include "fractal.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    fractal *dialog = new fractal;
   //renderarea *dialog= new renderarea;
 
    dialog->show();
    return app.exec();
}

#include <QApplication>
#include "fractal.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    fractal *dialog = new fractal;
   //renderarea *dialog= new renderarea;
 
    dialog->show();
    return app.exec();
}

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fractal.h:

#ifndef __FRACTAL_H__
#define __FRACTAL_H__
#include "ui_fractals.h"
 
 
class fractal : public QWidget, private Ui::Fractals
{
	Q_OBJECT
 
public:
	fractal(QWidget *parent = 0);
	void updateBrush();
//	bool eventFilter(QObject *o, QEvent *e);
public slots:
	void setOpenFileName();
	void paintEvent(QPaintEvent *event);
	bool eventFilter(QObject *o, QEvent *e);
};
 
 
#endif // __FRACTAL_H__

#ifndef __FRACTAL_H__
#define __FRACTAL_H__
#include "ui_fractals.h"


class fractal : public QWidget, private Ui::Fractals
{
	Q_OBJECT

public:
	fractal(QWidget *parent = 0);
	void updateBrush();
//	bool eventFilter(QObject *o, QEvent *e);
public slots:
	void setOpenFileName();
	void paintEvent(QPaintEvent *event);
	bool eventFilter(QObject *o, QEvent *e);
};

	
#endif // __FRACTAL_H__

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fractal.cpp:

#include <QFile>
#include <QGLWidget>
#include <QtOpenGL>
#include "fractal.h"
 
void tidyFile(QIODevice *inDevice, QIODevice *outDevice)
{
    QTextStream in(inDevice);
    QTextStream out(outDevice);
 
    int endlCount = 0;
    QChar ch;
 
    while (!in.atEnd()) {
        in >> ch;
 
        if (ch == '\n') {
            ++endlCount;
        }
    }
  //  out << endl;
}
 
 
fractal::fractal(QWidget *parent){
	setupUi(this);
	areadibujo->installEventFilter(this);
	connect( toolButton, SIGNAL( clicked() ), this, SLOT( setOpenFileName() ) );
	connect( boton_aceptar, SIGNAL( clicked() ), this, SLOT( QPaintEvent(QPainter *event) ) );
}
 
 
void fractal::setOpenFileName()
{
	 QFileDialog::Options options;
     options |=QFileDialog::ShowDirsOnly;
 
 
     QString selectedFilter;
     QString fileName = QFileDialog::getOpenFileName(this,
                                 tr("QFileDialog::getOpenFileName()"),
                                 lineEdit->text(),
                                 tr("Todos (*);;Data (*.txt)"),
                                 &selectedFilter,
                                 options);
     if (!fileName.isEmpty())
         lineEdit->setText(fileName);
 
     QFile infile;
     QFile outfile;
     infile.open(stdin, QFile::ReadOnly);
     outfile.open(stdout, QFile::WriteOnly);
     tidyFile(&infile,&outfile);
     QTextStream in(&infile);
     QTextStream out(&outfile);
     int endlCount = 0;
     QChar ch;
     while (!in.atEnd()) {
        in >> ch;
        if (ch == '\n') {
            ++endlCount;
        }
       }
}
 
void fractal::paintEvent(QPaintEvent *event){
	QPainter painter(this);
	painter.setRenderHint(QPainter::Antialiasing, true);
	painter.setPen(QPen(Qt::black, 15, Qt::SolidLine, Qt::RoundCap,
                   Qt::MiterJoin));
	painter.setBrush(QBrush(Qt::blue, Qt::DiagCrossPattern));
	painter.setPen(QPen(Qt::red, 5, Qt::SolidLine, Qt::RoundCap,Qt::MiterJoin));
 
	painter.translate(100.0,100.0);
	painter.drawPie(0, 0, 300, 300, 60 * 16, 270 * 16);
	painter.drawEllipse(30,30,60,60);
 
}
 
bool fractal::eventFilter(QObject *o, QEvent *e)
{
 if (o == areadibujo && e->type() == QEvent::Paint) {//process paint event of needed widget
      QPainter painter(areadibujo);
      painter.setPen(Qt::blue);
      painter.setFont(QFont("Arial", 30));
      painter.drawText(areadibujo->rect(), Qt::AlignCenter, "Qt");
      return true;
  }
    return fractal::eventFilter(o, e);
}

#include <QFile>
#include <QGLWidget>
#include <QtOpenGL>
#include "fractal.h"

void tidyFile(QIODevice *inDevice, QIODevice *outDevice)
{
    QTextStream in(inDevice);
    QTextStream out(outDevice);

    int endlCount = 0;
    QChar ch;

    while (!in.atEnd()) {
        in >> ch;

        if (ch == '\n') {
            ++endlCount;
        }
    }
  //  out << endl;
}


fractal::fractal(QWidget *parent){
	setupUi(this);
	areadibujo->installEventFilter(this);
	connect( toolButton, SIGNAL( clicked() ), this, SLOT( setOpenFileName() ) );
	connect( boton_aceptar, SIGNAL( clicked() ), this, SLOT( QPaintEvent(QPainter *event) ) );
}


void fractal::setOpenFileName()
{
	 QFileDialog::Options options;
     options |=QFileDialog::ShowDirsOnly;
     
        
     QString selectedFilter;
     QString fileName = QFileDialog::getOpenFileName(this,
                                 tr("QFileDialog::getOpenFileName()"),
                                 lineEdit->text(),
                                 tr("Todos (*);;Data (*.txt)"),
                                 &selectedFilter,
                                 options);
     if (!fileName.isEmpty())
         lineEdit->setText(fileName);
     
     QFile infile;
     QFile outfile;
     infile.open(stdin, QFile::ReadOnly);
     outfile.open(stdout, QFile::WriteOnly);
     tidyFile(&infile,&outfile);
     QTextStream in(&infile);
     QTextStream out(&outfile);
     int endlCount = 0;
     QChar ch;
     while (!in.atEnd()) {
        in >> ch;
        if (ch == '\n') {
            ++endlCount;
        }
       }
}

void fractal::paintEvent(QPaintEvent *event){
	QPainter painter(this);
	painter.setRenderHint(QPainter::Antialiasing, true);
	painter.setPen(QPen(Qt::black, 15, Qt::SolidLine, Qt::RoundCap,
                   Qt::MiterJoin));
	painter.setBrush(QBrush(Qt::blue, Qt::DiagCrossPattern));
	painter.setPen(QPen(Qt::red, 5, Qt::SolidLine, Qt::RoundCap,Qt::MiterJoin));
	
	painter.translate(100.0,100.0);
	painter.drawPie(0, 0, 300, 300, 60 * 16, 270 * 16);
	painter.drawEllipse(30,30,60,60);
	
}

bool fractal::eventFilter(QObject *o, QEvent *e)
{
 if (o == areadibujo && e->type() == QEvent::Paint) {//process paint event of needed widget
      QPainter painter(areadibujo);
      painter.setPen(Qt::blue);
      painter.setFont(QFont("Arial", 30));
      painter.drawText(areadibujo->rect(), Qt::AlignCenter, "Qt");
      return true;
  }
    return fractal::eventFilter(o, e);
}

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[spirit]

comment fractal:aintEvent and replace this snippet return fractal::eventFilter(o, e); with QWidget::eventFilter(o ,e);

[wysota]

Maybe it would be advised to at least take a brief look at the documentation of methods you are using?

[spirit]

look at this example in the attach, it should help you.

[j0rt4g4]

Ok I did that:
return fractal::eventFilter(o, e); with return QWidget::eventFilter(o ,e);

Finally solved.
Now how I can print what a QTextStream is reading in stdout?
(in the console)
Because I'm not sure that is opening and reading the file the way must be.
There are the first 2 implementation on the fractal.cpp.
Im trying to read a text file, with this format in C#
"0.065\t0.555\t0.5\n"

I tried counting lines first to know the number of items in array (I know this is not necessary in Qt because I should have used "array.append()" ) and make the QString a Qdouble making a "cast"...

I have been a week trying to do this for myself, and I got lot's and lot's of doubts.... I apologyze for asking that much... But If I knew I wouldn't ask...

[j0rt4g4]

Maybe it would be advised to at least take a brief look at the documentation of methods you are using?

I did that and I got all classes of QT what I'm ussing printed. But I was trying to go out of all my doubts YELLING FOR HELP...
I have many of examples printed but I dont want to bother but I want to learn... So I ask.
I'm sorry...

[wysota]

So don't print ALL, read the ones you need. If you have too much reference, you'll get lost in it. Focus on one task at a time.

[j0rt4g4]

look at this example in the attach, it should help you.

I look this example ... The event was a protected type of fractal ...
Thanks you very much for helping me.

I had that doubt for long time ago. But I'm sure it must be a easier way to do the things, but I'm doing the best of I can with my knowledge. I don't wanna be this noob anymore :P

So don't print ALL, read the ones you need. If you have too much reference, you'll get lost in it. Focus on one task at a time.

I printed the ones I think I would use for this. And I read them too. But the way is mading by walking through it . Finally, I want to thank you for your advise I would keep it in mind.

Sometimes reference is old (Qt3) and must be "correctly traslade" for working on Qt4, I have like 1 moths reading about this (Qt4.4.1 & Qt4.4.3, and I'm moving from C# languague to C++, I will learn, but be pacient), sometimes I got confused but testing is the way to get out of doubts.

[wysota]

All reference you may need is in your Qt Assistant. Just launch the application and enjoy. No need to browse any Qt3 docs.