Plug & Paint Example | Qt Widgets 5.13.0

Qt 5.13 | Qt Widgets | Plug & Paint Example

Qt 5.13.0 Reference Documentation

# Plug & Paint Example

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      #include "interfaces.h"
      #include "plugindialog.h"

      #include <QDir>
      #include <QGridLayout>
      #include <QHeaderView>
      #include <QLabel>
      #include <QPluginLoader>
      #include <QPushButton>
      #include <QStringList>
      #include <QTreeWidget>
      #include <QTreeWidgetItem>

      PluginDialog::PluginDialog(const QString &path, const QStringList &fileNames,
                                 QWidget *parent) :
          QDialog(parent),
          label(new QLabel),
          treeWidget(new QTreeWidget),
          okButton(new QPushButton(tr("OK")))
      {
          treeWidget->setAlternatingRowColors(false);
          treeWidget->setSelectionMode(QAbstractItemView::NoSelection);
          treeWidget->setColumnCount(1);
          treeWidget->header()->hide();

          okButton->setDefault(true);

          connect(okButton, &QAbstractButton::clicked, this, &QWidget::close);

          QGridLayout *mainLayout = new QGridLayout;
          mainLayout->setColumnStretch(0, 1);
          mainLayout->setColumnStretch(2, 1);
          mainLayout->addWidget(label, 0, 0, 1, 3);
          mainLayout->addWidget(treeWidget, 1, 0, 1, 3);
          mainLayout->addWidget(okButton, 2, 1);
          setLayout(mainLayout);

          interfaceIcon.addPixmap(style()->standardPixmap(QStyle::SP_DirOpenIcon),
                                  QIcon::Normal, QIcon::On);
          interfaceIcon.addPixmap(style()->standardPixmap(QStyle::SP_DirClosedIcon),
                                  QIcon::Normal, QIcon::Off);
          featureIcon.addPixmap(style()->standardPixmap(QStyle::SP_FileIcon));

          setWindowTitle(tr("Plugin Information"));
          findPlugins(path, fileNames);
      }

      void PluginDialog::findPlugins(const QString &path,
                                     const QStringList &fileNames)
      {
          label->setText(tr("Plug & Paint found the following plugins\n"
                            "(looked in %1):")
                         .arg(QDir::toNativeSeparators(path)));

          const QDir dir(path);

          const auto staticInstances = QPluginLoader::staticInstances();
          for (QObject *plugin : staticInstances)
              populateTreeWidget(plugin, tr("%1 (Static Plugin)")
                                         .arg(plugin->metaObject()->className()));

          for (const QString &fileName : fileNames) {
              QPluginLoader loader(dir.absoluteFilePath(fileName));
              QObject *plugin = loader.instance();
              if (plugin)
                  populateTreeWidget(plugin, fileName);
          }
      }

      void PluginDialog::populateTreeWidget(QObject *plugin, const QString &text)
      {
          auto pluginItem = new QTreeWidgetItem(treeWidget);
          pluginItem->setText(0, text);
          pluginItem->setExpanded(true);

          QFont boldFont = pluginItem->font(0);
          boldFont.setBold(true);
          pluginItem->setFont(0, boldFont);

          if (plugin) {
              auto iBrush = qobject_cast<BrushInterface *>(plugin);
              if (iBrush)
                  addItems(pluginItem, "BrushInterface", iBrush->brushes());

              auto iShape = qobject_cast<ShapeInterface *>(plugin);
              if (iShape)
                  addItems(pluginItem, "ShapeInterface", iShape->shapes());

              auto iFilter = qobject_cast<FilterInterface *>(plugin);
              if (iFilter)
                  addItems(pluginItem, "FilterInterface", iFilter->filters());
          }
      }

      void PluginDialog::addItems(QTreeWidgetItem *pluginItem,
                                  const char *interfaceName,
                                  const QStringList &features)
      {
          auto interfaceItem = new QTreeWidgetItem(pluginItem);
          interfaceItem->setText(0, interfaceName);
          interfaceItem->setIcon(0, interfaceIcon);

          for (QString feature : features) {
              if (feature.endsWith("..."))
                  feature.chop(3);
              auto featureItem = new QTreeWidgetItem(interfaceItem);
              featureItem->setText(0, feature);
              featureItem->setIcon(0, featureIcon);
          }
      }