Qt 5.11 | Qt Widgets | Character Map Example | characterwidget.cpp Example File

Qt 5.11.3 Reference Documentation

# characterwidget.cpp Example File

widgets/charactermap/characterwidget.cpp

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      #include <QtWidgets>

      #include "characterwidget.h"

      CharacterWidget::CharacterWidget(QWidget *parent)
          : QWidget(parent), columns(16), lastKey(-1)
      {
          calculateSquareSize();
          setMouseTracking(true);
      }

      void CharacterWidget::updateFont(const QFont &font)
      {
          displayFont.setFamily(font.family());
          calculateSquareSize();
          adjustSize();
          update();
      }

      void CharacterWidget::updateSize(const QString &fontSize)
      {
          displayFont.setPointSize(fontSize.toInt());
          calculateSquareSize();
          adjustSize();
          update();
      }

      void CharacterWidget::updateStyle(const QString &fontStyle)
      {
          QFontDatabase fontDatabase;
          const QFont::StyleStrategy oldStrategy = displayFont.styleStrategy();
          displayFont = fontDatabase.font(displayFont.family(), fontStyle, displayFont.pointSize());
          displayFont.setStyleStrategy(oldStrategy);
          calculateSquareSize();
          adjustSize();
          update();
      }

      void CharacterWidget::updateFontMerging(bool enable)
      {
          if (enable)
              displayFont.setStyleStrategy(QFont::PreferDefault);
          else
              displayFont.setStyleStrategy(QFont::NoFontMerging);
          adjustSize();
          update();
      }

      void CharacterWidget::calculateSquareSize()
      {
          squareSize = qMax(16, 4 + QFontMetrics(displayFont, this).height());
      }

      QSize CharacterWidget::sizeHint() const
      {
          return QSize(columns*squareSize, (65536/columns)*squareSize);
      }

      void CharacterWidget::mouseMoveEvent(QMouseEvent *event)
      {
          QPoint widgetPosition = mapFromGlobal(event->globalPos());
          uint key = (widgetPosition.y()/squareSize)*columns + widgetPosition.x()/squareSize;

          QString text = QString::fromLatin1("<p>Character: <span style=\"font-size: 24pt; font-family: %1\">").arg(displayFont.family())
                        + QChar(key)
                        + QString::fromLatin1("</span><p>Value: 0x")
                        + QString::number(key, 16);
          QToolTip::showText(event->globalPos(), text, this);
      }

      void CharacterWidget::mousePressEvent(QMouseEvent *event)
      {
          if (event->button() == Qt::LeftButton) {
              lastKey = (event->y()/squareSize)*columns + event->x()/squareSize;
              if (QChar(lastKey).category() != QChar::Other_NotAssigned)
                  emit characterSelected(QString(QChar(lastKey)));
              update();
          }
          else
              QWidget::mousePressEvent(event);
      }

      void CharacterWidget::paintEvent(QPaintEvent *event)
      {
          QPainter painter(this);
          painter.fillRect(event->rect(), QBrush(Qt::white));
          painter.setFont(displayFont);

          QRect redrawRect = event->rect();
          int beginRow = redrawRect.top()/squareSize;
          int endRow = redrawRect.bottom()/squareSize;
          int beginColumn = redrawRect.left()/squareSize;
          int endColumn = redrawRect.right()/squareSize;

          painter.setPen(QPen(Qt::gray));
          for (int row = beginRow; row <= endRow; ++row) {
              for (int column = beginColumn; column <= endColumn; ++column) {
                  painter.drawRect(column*squareSize, row*squareSize, squareSize, squareSize);
              }
          }

          QFontMetrics fontMetrics(displayFont);
          painter.setPen(QPen(Qt::black));
          for (int row = beginRow; row <= endRow; ++row) {

              for (int column = beginColumn; column <= endColumn; ++column) {

                  int key = row*columns + column;
                  painter.setClipRect(column*squareSize, row*squareSize, squareSize, squareSize);

                  if (key == lastKey)
                      painter.fillRect(column*squareSize + 1, row*squareSize + 1, squareSize, squareSize, QBrush(Qt::red));

                  painter.drawText(column*squareSize + (squareSize / 2) - fontMetrics.horizontalAdvance(QChar(key))/2,
                                   row*squareSize + 4 + fontMetrics.ascent(),
                                   QString(QChar(key)));
              }
          }
      }