iconpreviewarea.cpp Example File

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  #include <QtWidgets>

  #include "iconpreviewarea.h"

  IconPreviewArea::IconPreviewArea(QWidget *parent)
      : QWidget(parent)
  {
      QGridLayout *mainLayout = new QGridLayout(this);

      for (int row = 0; row < NumStates; ++row) {
          stateLabels[row] = createHeaderLabel(IconPreviewArea::iconStateNames().at(row));
          mainLayout->addWidget(stateLabels[row], row + 1, 0);
      }
      Q_ASSERT(NumStates == 2);

      for (int column = 0; column < NumModes; ++column) {
          modeLabels[column] = createHeaderLabel(IconPreviewArea::iconModeNames().at(column));
          mainLayout->addWidget(modeLabels[column], 0, column + 1);
      }
      Q_ASSERT(NumModes == 4);

      for (int column = 0; column < NumModes; ++column) {
          for (int row = 0; row < NumStates; ++row) {
              pixmapLabels[column][row] = createPixmapLabel();
              mainLayout->addWidget(pixmapLabels[column][row], row + 1, column + 1);
          }
      }
  }

  #ifdef Q_COMPILER_INITIALIZER_LISTS

  QVector<QIcon::Mode> IconPreviewArea::iconModes()
  {
      static const QVector<QIcon::Mode> result = {QIcon::Normal, QIcon::Active, QIcon::Disabled, QIcon::Selected};
      return result;
  }

  QVector<QIcon::State> IconPreviewArea::iconStates()
  {
      static const QVector<QIcon::State> result = {QIcon::Off, QIcon::On};
      return result;
  }

  QStringList IconPreviewArea::iconModeNames()
  {
      static const QStringList result = {tr("Normal"), tr("Active"), tr("Disabled"), tr("Selected")};
      return result;
  }

  QStringList IconPreviewArea::iconStateNames()
  {
      static const QStringList result = {tr("Off"), tr("On")};
      return result;
  }

  #else // Q_COMPILER_INITIALIZER_LISTS

  QVector<QIcon::Mode> IconPreviewArea::iconModes()
  {
      static QVector<QIcon::Mode> result;
      if (result.isEmpty())
          result << QIcon::Normal << QIcon::Active << QIcon::Disabled << QIcon::Selected;
      return result;
  }

  QVector<QIcon::State> IconPreviewArea::iconStates()
  {
      static QVector<QIcon::State> result;
      if (result.isEmpty())
          result << QIcon::Off << QIcon::On;
      return result;
  }

  QStringList IconPreviewArea::iconModeNames()
  {
      static QStringList result;
      if (result.isEmpty())
          result << tr("Normal") << tr("Active") << tr("Disabled") << tr("Selected");
      return result;
  }

  QStringList IconPreviewArea::iconStateNames()
  {
      static QStringList result;
      if (result.isEmpty())
          result << tr("Off") << tr("On");
      return result;
  }

  #endif // !Q_COMPILER_INITIALIZER_LISTS

  void IconPreviewArea::setIcon(const QIcon &icon)
  {
      this->icon = icon;
      updatePixmapLabels();
  }

  void IconPreviewArea::setSize(const QSize &size)
  {
      if (size != this->size) {
          this->size = size;
          updatePixmapLabels();
      }
  }

  QLabel *IconPreviewArea::createHeaderLabel(const QString &text)
  {
      QLabel *label = new QLabel(tr("<b>%1</b>").arg(text));
      label->setAlignment(Qt::AlignCenter);
      return label;
  }

  QLabel *IconPreviewArea::createPixmapLabel()
  {
      QLabel *label = new QLabel;
      label->setEnabled(false);
      label->setAlignment(Qt::AlignCenter);
      label->setFrameShape(QFrame::Box);
      label->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
      label->setBackgroundRole(QPalette::Base);
      label->setAutoFillBackground(true);
      label->setMinimumSize(132, 132);
      return label;
  }

  void IconPreviewArea::updatePixmapLabels()
  {
      QWindow *window = Q_NULLPTR;
      if (const QWidget *nativeParent = nativeParentWidget())
          window = nativeParent->windowHandle();
      for (int column = 0; column < NumModes; ++column) {
          for (int row = 0; row < NumStates; ++row) {
              const QPixmap pixmap =
                  icon.pixmap(window, size, IconPreviewArea::iconModes().at(column),
                              IconPreviewArea::iconStates().at(row));
              QLabel *pixmapLabel = pixmapLabels[column][row];
              pixmapLabel->setPixmap(pixmap);
              pixmapLabel->setEnabled(!pixmap.isNull());
              QString toolTip;
              if (!pixmap.isNull()) {
                  const QSize actualSize = icon.actualSize(size);
                  toolTip =
                      tr("Size: %1x%2\nActual size: %3x%4\nDevice pixel ratio: %5")
                          .arg(size.width()).arg(size.height())
                          .arg(actualSize.width()).arg(actualSize.height())
                          .arg(pixmap.devicePixelRatioF());
              }
              pixmapLabel->setToolTip(toolTip);
          }
      }
  }