window.cpp Example File

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  #include "renderarea.h"
  #include "window.h"

  #include <QtWidgets>

  #include <cmath>

  const float Pi = 3.14159f;

  Window::Window()
  {
      QPainterPath rectPath;
      rectPath.moveTo(20.0, 30.0);
      rectPath.lineTo(80.0, 30.0);
      rectPath.lineTo(80.0, 70.0);
      rectPath.lineTo(20.0, 70.0);
      rectPath.closeSubpath();

      QPainterPath roundRectPath;
      roundRectPath.moveTo(80.0, 35.0);
      roundRectPath.arcTo(70.0, 30.0, 10.0, 10.0, 0.0, 90.0);
      roundRectPath.lineTo(25.0, 30.0);
      roundRectPath.arcTo(20.0, 30.0, 10.0, 10.0, 90.0, 90.0);
      roundRectPath.lineTo(20.0, 65.0);
      roundRectPath.arcTo(20.0, 60.0, 10.0, 10.0, 180.0, 90.0);
      roundRectPath.lineTo(75.0, 70.0);
      roundRectPath.arcTo(70.0, 60.0, 10.0, 10.0, 270.0, 90.0);
      roundRectPath.closeSubpath();

      QPainterPath ellipsePath;
      ellipsePath.moveTo(80.0, 50.0);
      ellipsePath.arcTo(20.0, 30.0, 60.0, 40.0, 0.0, 360.0);

      QPainterPath piePath;
      piePath.moveTo(50.0, 50.0);
      piePath.arcTo(20.0, 30.0, 60.0, 40.0, 60.0, 240.0);
      piePath.closeSubpath();

      QPainterPath polygonPath;
      polygonPath.moveTo(10.0, 80.0);
      polygonPath.lineTo(20.0, 10.0);
      polygonPath.lineTo(80.0, 30.0);
      polygonPath.lineTo(90.0, 70.0);
      polygonPath.closeSubpath();

      QPainterPath groupPath;
      groupPath.moveTo(60.0, 40.0);
      groupPath.arcTo(20.0, 20.0, 40.0, 40.0, 0.0, 360.0);
      groupPath.moveTo(40.0, 40.0);
      groupPath.lineTo(40.0, 80.0);
      groupPath.lineTo(80.0, 80.0);
      groupPath.lineTo(80.0, 40.0);
      groupPath.closeSubpath();

      QPainterPath textPath;
      QFont timesFont("Times", 50);
      timesFont.setStyleStrategy(QFont::ForceOutline);
      textPath.addText(10, 70, timesFont, tr("Qt"));

      QPainterPath bezierPath;
      bezierPath.moveTo(20, 30);
      bezierPath.cubicTo(80, 0, 50, 50, 80, 80);

      QPainterPath starPath;
      starPath.moveTo(90, 50);
      for (int i = 1; i < 5; ++i) {
          starPath.lineTo(50 + 40 * std::cos(0.8 * i * Pi),
                          50 + 40 * std::sin(0.8 * i * Pi));
      }
      starPath.closeSubpath();

      renderAreas.push_back(new RenderArea(rectPath));
      renderAreas.push_back(new RenderArea(roundRectPath));
      renderAreas.push_back(new RenderArea(ellipsePath));
      renderAreas.push_back(new RenderArea(piePath));
      renderAreas.push_back(new RenderArea(polygonPath));
      renderAreas.push_back(new RenderArea(groupPath));
      renderAreas.push_back(new RenderArea(textPath));
      renderAreas.push_back(new RenderArea(bezierPath));
      renderAreas.push_back(new RenderArea(starPath));

      fillRuleComboBox = new QComboBox;
      fillRuleComboBox->addItem(tr("Odd Even"), Qt::OddEvenFill);
      fillRuleComboBox->addItem(tr("Winding"), Qt::WindingFill);

      fillRuleLabel = new QLabel(tr("Fill &Rule:"));
      fillRuleLabel->setBuddy(fillRuleComboBox);

      fillColor1ComboBox = new QComboBox;
      populateWithColors(fillColor1ComboBox);
      fillColor1ComboBox->setCurrentIndex(fillColor1ComboBox->findText("mediumslateblue"));

      fillColor2ComboBox = new QComboBox;
      populateWithColors(fillColor2ComboBox);
      fillColor2ComboBox->setCurrentIndex(fillColor2ComboBox->findText("cornsilk"));

      fillGradientLabel = new QLabel(tr("&Fill Gradient:"));
      fillGradientLabel->setBuddy(fillColor1ComboBox);

      fillToLabel = new QLabel(tr("to"));
      fillToLabel->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

      penWidthSpinBox = new QSpinBox;
      penWidthSpinBox->setRange(0, 20);

      penWidthLabel = new QLabel(tr("&Pen Width:"));
      penWidthLabel->setBuddy(penWidthSpinBox);

      penColorComboBox = new QComboBox;
      populateWithColors(penColorComboBox);
      penColorComboBox->setCurrentIndex(penColorComboBox->findText("darkslateblue"));

      penColorLabel = new QLabel(tr("Pen &Color:"));
      penColorLabel->setBuddy(penColorComboBox);

      rotationAngleSpinBox = new QSpinBox;
      rotationAngleSpinBox->setRange(0, 359);
      rotationAngleSpinBox->setWrapping(true);
      rotationAngleSpinBox->setSuffix(QLatin1String("\xB0"));

      rotationAngleLabel = new QLabel(tr("&Rotation Angle:"));
      rotationAngleLabel->setBuddy(rotationAngleSpinBox);

      connect(fillRuleComboBox, SIGNAL(activated(int)), this, SLOT(fillRuleChanged()));
      connect(fillColor1ComboBox, SIGNAL(activated(int)), this, SLOT(fillGradientChanged()));
      connect(fillColor2ComboBox, SIGNAL(activated(int)), this, SLOT(fillGradientChanged()));
      connect(penColorComboBox, SIGNAL(activated(int)), this, SLOT(penColorChanged()));

      for(QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); it++) {
          connect(penWidthSpinBox, SIGNAL(valueChanged(int)), *it, SLOT(setPenWidth(int)));
          connect(rotationAngleSpinBox, SIGNAL(valueChanged(int)), *it, SLOT(setRotationAngle(int)));
      }

      QGridLayout *topLayout = new QGridLayout;

      int i=0;
      for(QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); it++, i++)
          topLayout->addWidget(*it, i / 3, i % 3);

      QGridLayout *mainLayout = new QGridLayout;
      mainLayout->addLayout(topLayout, 0, 0, 1, 4);
      mainLayout->addWidget(fillRuleLabel, 1, 0);
      mainLayout->addWidget(fillRuleComboBox, 1, 1, 1, 3);
      mainLayout->addWidget(fillGradientLabel, 2, 0);
      mainLayout->addWidget(fillColor1ComboBox, 2, 1);
      mainLayout->addWidget(fillToLabel, 2, 2);
      mainLayout->addWidget(fillColor2ComboBox, 2, 3);
      mainLayout->addWidget(penWidthLabel, 3, 0);
      mainLayout->addWidget(penWidthSpinBox, 3, 1, 1, 3);
      mainLayout->addWidget(penColorLabel, 4, 0);
      mainLayout->addWidget(penColorComboBox, 4, 1, 1, 3);
      mainLayout->addWidget(rotationAngleLabel, 5, 0);
      mainLayout->addWidget(rotationAngleSpinBox, 5, 1, 1, 3);
      setLayout(mainLayout);

      fillRuleChanged();
      fillGradientChanged();
      penColorChanged();
      penWidthSpinBox->setValue(2);

      setWindowTitle(tr("Painter Paths"));
  }

  void Window::fillRuleChanged()
  {
      Qt::FillRule rule = (Qt::FillRule)currentItemData(fillRuleComboBox).toInt();

      for (QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); ++it)
          (*it)->setFillRule(rule);
  }

  void Window::fillGradientChanged()
  {
      QColor color1 = qvariant_cast<QColor>(currentItemData(fillColor1ComboBox));
      QColor color2 = qvariant_cast<QColor>(currentItemData(fillColor2ComboBox));

      for (QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); ++it)
          (*it)->setFillGradient(color1, color2);
  }

  void Window::penColorChanged()
  {
      QColor color = qvariant_cast<QColor>(currentItemData(penColorComboBox));

      for (QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); ++it)
          (*it)->setPenColor(color);
  }

  void Window::populateWithColors(QComboBox *comboBox)
  {
      QStringList colorNames = QColor::colorNames();
      foreach (QString name, colorNames)
          comboBox->addItem(name, QColor(name));
  }

  QVariant Window::currentItemData(QComboBox *comboBox)
  {
      return comboBox->itemData(comboBox->currentIndex());
  }