Qt project file


#-------------------------------------------------

#

# Project created by QtCreator 2010-08-13T11:59:16

#

#-------------------------------------------------



QT       += core gui



TARGET = CppDrawGlobe

TEMPLATE = app





SOURCES += main.cpp\

        dialog.cpp



HEADERS  += dialog.h



FORMS    += dialog.ui



RESOURCES += \

    resources.qrc

dialog.cpp


#include <iostream>

#include <boost/lexical_cast.hpp>

#include <boost/numeric/conversion/cast.hpp>



#include <QDesktopWidget>



#include "dialog.h"

#include "ui_dialog.h"



Dialog::Dialog(QWidget *parent) :

    QDialog(parent, Qt::Window),

    ui(new Ui::Dialog)

{

  ui->setupUi(this);

  QObject::connect(ui->dial_r,SIGNAL(valueChanged(int)),this,SLOT(onAnyChange()));

  QObject::connect(ui->dial_g,SIGNAL(valueChanged(int)),this,SLOT(onAnyChange()));

  QObject::connect(ui->dial_b,SIGNAL(valueChanged(int)),this,SLOT(onAnyChange()));



  //Put the dialog in the screen center

  const QRect screen = QApplication::desktop()->screenGeometry();

  this->move( screen.center() - this->rect().center() );

}



Dialog::~Dialog()

{

  delete ui;

}



void Dialog::changeEvent(QEvent *e)

{

  QDialog::changeEvent(e);

  switch (e->type()) {

  case QEvent::LanguageChange:

    ui->retranslateUi(this);

    break;

  default:

    break;

  }

}



void Dialog::onAnyChange()

{



  ui->label_r->setText("Red: "

    + QString(boost::lexical_cast<std::string>(ui->dial_r->sliderPosition()).c_str()));

  ui->label_g->setText("Green: "

    + QString(boost::lexical_cast<std::string>(ui->dial_g->sliderPosition()).c_str()));

  ui->label_b->setText("Blue: "

    + QString(boost::lexical_cast<std::string>(ui->dial_b->sliderPosition()).c_str()));



  ui->label->setPixmap(

    DrawGlobe(

      ui->label->width(),

      ui->label->height(),

      ui->dial_r->sliderPosition(),

      ui->dial_g->sliderPosition(),

      ui->dial_b->sliderPosition()));

}



void Dialog::resizeEvent(QResizeEvent*)

{

  this->onAnyChange();

}



//From http://www.richelbilderbeek.nl/CppDrawGlobe.htm

QPixmap DrawGlobe(

  const int width,

  const int height,

  const unsigned char r,

  const unsigned char g,

  const unsigned char b)

{

  QPixmap pixmap(width,height);

  QImage image = pixmap.toImage();



  assert(image.bytesPerLine() / width == 4

    && "Assume there are 4 bytes per pixel");



  const double r_max = boost::numeric_cast<double>(r);

  const double g_max = boost::numeric_cast<double>(g);

  const double b_max = boost::numeric_cast<double>(b);

  const double midX = boost::numeric_cast<double>(width ) / 2.0;

  const double midY = boost::numeric_cast<double>(height) / 2.0;

  const double max_dist = std::min(midX,midY);



  for (int y=0; y!=height; ++y)

  {



    unsigned char * const line

      = static_cast<unsigned char *>(image.scanLine(y));

    const double y_d = boost::numeric_cast<double>(y);

    for (int x=0; x!=width; ++x)

    {

      const double x_d = boost::numeric_cast<double>(x);

      const double dist

        = std::sqrt(

            ((x_d - midX) * (x_d - midX))

          + ((y_d - midY) * (y_d - midY)) );

      if (dist <= max_dist)

      {

        const double rel_dist = dist / max_dist;

        const int r_here = rel_dist * r_max;

        const int g_here = rel_dist * g_max;

        const int b_here = rel_dist * b_max;

        assert( r_here >= 0);

        assert( r_here < 256);

        assert( g_here >= 0);

        assert( g_here < 256);

        assert( b_here >= 0);

        assert( b_here < 256);

        line[x*4+3] = 255; //Alpha value

        //New color values are 1 at least

        line[x*4+2] = (r_here == 0 ? 1 : r_here); //Red

        line[x*4+1] = (g_here == 0 ? 1 : g_here); //Green

        line[x*4+0] = (b_here == 0 ? 1 : b_here); //Blue

      }

      else

      {

        line[x*4+3] = 0; //Alpha value

        line[x*4+2] = 0; //Red

        line[x*4+1] = 0; //Green

        line[x*4+0] = 0; //Blue

      }

    }

  }

  pixmap = pixmap.fromImage(image);



  //Add transparency

  const QBitmap mask = pixmap.createMaskFromColor(QColor(0,0,0,0).rgb());

  pixmap.setMask(mask);



  return pixmap;

}

dialog.h


#ifndef DIALOG_H

#define DIALOG_H



#include <boost/shared_ptr.hpp>

#include <QDialog>



namespace Ui {

  class Dialog;

}



class Dialog : public QDialog

{

  Q_OBJECT



public:

  explicit Dialog(QWidget *parent = 0);

  ~Dialog();



protected:

  void changeEvent(QEvent *e);



private:

  Ui::Dialog *ui;

  void resizeEvent(QResizeEvent*);



private slots:

  void onAnyChange();

};



#endif // DIALOG_H



//From http://www.richelbilderbeek.nl/CppDrawGlobe.htm

QPixmap DrawGlobe(

  const int width,

  const int height,

  const unsigned char r,

  const unsigned char g,

  const unsigned char b);

main.cpp


#include <QtGui/QApplication>

#include "dialog.h"



int main(int argc, char *argv[])

{

    QApplication a(argc, argv);

    Dialog w;

    w.show();



    return a.exec();

}

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(C++) DrawGlobeQt

Qt project file

dialog.cpp

dialog.h

main.cpp