Qt 5.6 | Qt Widgets | Vector Deformation | pathdeform.cpp Example File

Qt 5.6.2 Reference Documentation

# pathdeform.cpp Example File

painting/deform/pathdeform.cpp

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      **
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      ** Contact: http://www.qt.io/licensing/
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      ** This file is part of the demonstration applications of the Qt Toolkit.
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      #include "pathdeform.h"

      #include <QApplication>
      #include <QtDebug>
      #include <QMouseEvent>
      #include <QTimerEvent>
      #include <QLayout>
      #include <QLineEdit>
      #include <QPainter>
      #include <QSlider>
      #include <QLabel>
      #include <QDesktopWidget>
      #include <qmath.h>

      PathDeformControls::PathDeformControls(QWidget *parent,
                                             PathDeformRenderer* renderer, bool smallScreen)
            : QWidget(parent)
      {
          m_renderer = renderer;

          if (smallScreen)
              layoutForSmallScreen();
          else
              layoutForDesktop();
      }

      void PathDeformControls::layoutForDesktop()
      {
          QGroupBox* mainGroup = new QGroupBox(this);
          mainGroup->setTitle(tr("Controls"));

          QGroupBox *radiusGroup = new QGroupBox(mainGroup);
          radiusGroup->setTitle(tr("Lens Radius"));
          QSlider *radiusSlider = new QSlider(Qt::Horizontal, radiusGroup);
          radiusSlider->setRange(15, 150);
          radiusSlider->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);

          QGroupBox *deformGroup = new QGroupBox(mainGroup);
          deformGroup->setTitle(tr("Deformation"));
          QSlider *deformSlider = new QSlider(Qt::Horizontal, deformGroup);
          deformSlider->setRange(-100, 100);
          deformSlider->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);

          QGroupBox *fontSizeGroup = new QGroupBox(mainGroup);
          fontSizeGroup->setTitle(tr("Font Size"));
          QSlider *fontSizeSlider = new QSlider(Qt::Horizontal, fontSizeGroup);
          fontSizeSlider->setRange(16, 200);
          fontSizeSlider->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);

          QGroupBox *textGroup = new QGroupBox(mainGroup);
          textGroup->setTitle(tr("Text"));
          QLineEdit *textInput = new QLineEdit(textGroup);

          QPushButton *animateButton = new QPushButton(mainGroup);
          animateButton->setText(tr("Animated"));
          animateButton->setCheckable(true);

          QPushButton *showSourceButton = new QPushButton(mainGroup);
          showSourceButton->setText(tr("Show Source"));

      #ifdef QT_OPENGL_SUPPORT
          QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
          enableOpenGLButton->setText(tr("Use OpenGL"));
          enableOpenGLButton->setCheckable(true);
          enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
          if (!QGLFormat::hasOpenGL())
              enableOpenGLButton->hide();
      #endif

          QPushButton *whatsThisButton = new QPushButton(mainGroup);
          whatsThisButton->setText(tr("What's This?"));
          whatsThisButton->setCheckable(true);

          mainGroup->setFixedWidth(180);

          QVBoxLayout *mainGroupLayout = new QVBoxLayout(mainGroup);
          mainGroupLayout->addWidget(radiusGroup);
          mainGroupLayout->addWidget(deformGroup);
          mainGroupLayout->addWidget(fontSizeGroup);
          mainGroupLayout->addWidget(textGroup);
          mainGroupLayout->addWidget(animateButton);
          mainGroupLayout->addStretch(1);
      #ifdef QT_OPENGL_SUPPORT
          mainGroupLayout->addWidget(enableOpenGLButton);
      #endif
          mainGroupLayout->addWidget(showSourceButton);
          mainGroupLayout->addWidget(whatsThisButton);

          QVBoxLayout *radiusGroupLayout = new QVBoxLayout(radiusGroup);
          radiusGroupLayout->addWidget(radiusSlider);

          QVBoxLayout *deformGroupLayout = new QVBoxLayout(deformGroup);
          deformGroupLayout->addWidget(deformSlider);

          QVBoxLayout *fontSizeGroupLayout = new QVBoxLayout(fontSizeGroup);
          fontSizeGroupLayout->addWidget(fontSizeSlider);

          QVBoxLayout *textGroupLayout = new QVBoxLayout(textGroup);
          textGroupLayout->addWidget(textInput);

          QVBoxLayout * mainLayout = new QVBoxLayout(this);
          mainLayout->addWidget(mainGroup);
          mainLayout->setMargin(0);

          connect(radiusSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setRadius(int)));
          connect(deformSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setIntensity(int)));
          connect(fontSizeSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setFontSize(int)));
          connect(animateButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setAnimated(bool)));
      #ifdef QT_OPENGL_SUPPORT
          connect(enableOpenGLButton, SIGNAL(clicked(bool)), m_renderer, SLOT(enableOpenGL(bool)));
      #endif

          connect(textInput, SIGNAL(textChanged(QString)), m_renderer, SLOT(setText(QString)));
          connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
                  whatsThisButton, SLOT(setChecked(bool)));
          connect(whatsThisButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setDescriptionEnabled(bool)));
          connect(showSourceButton, SIGNAL(clicked()), m_renderer, SLOT(showSource()));

          animateButton->animateClick();
          deformSlider->setValue(80);
          fontSizeSlider->setValue(120);
          radiusSlider->setValue(100);
          textInput->setText(tr("Qt"));
      }

      void PathDeformControls::layoutForSmallScreen()
      {
          QGroupBox* mainGroup = new QGroupBox(this);
          mainGroup->setTitle(tr("Controls"));

          QLabel *radiusLabel = new QLabel(mainGroup);
          radiusLabel->setText(tr("Lens Radius:"));
          QSlider *radiusSlider = new QSlider(Qt::Horizontal, mainGroup);
          radiusSlider->setRange(15, 150);
          radiusSlider->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

          QLabel *deformLabel = new QLabel(mainGroup);
          deformLabel->setText(tr("Deformation:"));
          QSlider *deformSlider = new QSlider(Qt::Horizontal, mainGroup);
          deformSlider->setRange(-100, 100);
          deformSlider->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

          QLabel *fontSizeLabel = new QLabel(mainGroup);
          fontSizeLabel->setText(tr("Font Size:"));
          QSlider *fontSizeSlider = new QSlider(Qt::Horizontal, mainGroup);
          fontSizeSlider->setRange(16, 200);
          fontSizeSlider->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

          QPushButton *animateButton = new QPushButton(tr("Animated"), mainGroup);
          animateButton->setCheckable(true);

      #ifdef QT_OPENGL_SUPPORT
          QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
          enableOpenGLButton->setText(tr("Use OpenGL"));
          enableOpenGLButton->setCheckable(mainGroup);
          enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
          if (!QGLFormat::hasOpenGL())
              enableOpenGLButton->hide();
      #endif

          QPushButton *quitButton = new QPushButton(tr("Quit"), mainGroup);
          QPushButton *okButton = new QPushButton(tr("OK"), mainGroup);

          QGridLayout *mainGroupLayout = new QGridLayout(mainGroup);
          mainGroupLayout->setMargin(0);
          mainGroupLayout->addWidget(radiusLabel, 0, 0, Qt::AlignRight);
          mainGroupLayout->addWidget(radiusSlider, 0, 1);
          mainGroupLayout->addWidget(deformLabel, 1, 0, Qt::AlignRight);
          mainGroupLayout->addWidget(deformSlider, 1, 1);
          mainGroupLayout->addWidget(fontSizeLabel, 2, 0, Qt::AlignRight);
          mainGroupLayout->addWidget(fontSizeSlider, 2, 1);
          mainGroupLayout->addWidget(animateButton, 3,0, 1,2);
      #ifdef QT_OPENGL_SUPPORT
          mainGroupLayout->addWidget(enableOpenGLButton, 4,0, 1,2);
      #endif

          QVBoxLayout *mainLayout = new QVBoxLayout(this);
          mainLayout->addWidget(mainGroup);
          mainLayout->addStretch(1);
          mainLayout->addWidget(okButton);
          mainLayout->addWidget(quitButton);

          connect(quitButton, SIGNAL(clicked()), this, SIGNAL(quitPressed()));
          connect(okButton, SIGNAL(clicked()), this, SIGNAL(okPressed()));
          connect(radiusSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setRadius(int)));
          connect(deformSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setIntensity(int)));
          connect(fontSizeSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setFontSize(int)));
          connect(animateButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setAnimated(bool)));
      #ifdef QT_OPENGL_SUPPORT
          connect(enableOpenGLButton, SIGNAL(clicked(bool)), m_renderer, SLOT(enableOpenGL(bool)));
      #endif

          animateButton->animateClick();
          deformSlider->setValue(80);
          fontSizeSlider->setValue(120);

          QRect screen_size = QApplication::desktop()->screenGeometry();
          radiusSlider->setValue(qMin(screen_size.width(), screen_size.height())/5);

          m_renderer->setText(tr("Qt"));
      }

      PathDeformWidget::PathDeformWidget(QWidget *parent, bool smallScreen)
          : QWidget(parent)
      {
          setWindowTitle(tr("Vector Deformation"));

          m_renderer = new PathDeformRenderer(this, smallScreen);
          m_renderer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

          // Layouts
          QHBoxLayout *mainLayout = new QHBoxLayout(this);
          mainLayout->addWidget(m_renderer);

          m_controls = new PathDeformControls(0, m_renderer, smallScreen);
          m_controls->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Minimum);

          if (!smallScreen)
              mainLayout->addWidget(m_controls);

          m_renderer->loadSourceFile(":res/deform/pathdeform.cpp");
          m_renderer->loadDescription(":res/deform/pathdeform.html");
          m_renderer->setDescriptionEnabled(false);

          connect(m_renderer, SIGNAL(clicked()), this, SLOT(showControls()));
          connect(m_controls, SIGNAL(okPressed()), this, SLOT(hideControls()));
          connect(m_controls, SIGNAL(quitPressed()), QApplication::instance(), SLOT(quit()));
      }

      void PathDeformWidget::showControls()
      {
          m_controls->showFullScreen();
      }

      void PathDeformWidget::hideControls()
      {
          m_controls->hide();
      }

      void PathDeformWidget::setStyle( QStyle * style )
      {
          QWidget::setStyle(style);
          if (m_controls == 0)
              return;

          m_controls->setStyle(style);

          QList<QWidget *> widgets = m_controls->findChildren<QWidget *>();
          foreach (QWidget *w, widgets)
              w->setStyle(style);
      }

      static inline QRect circle_bounds(const QPointF &center, qreal radius, qreal compensation)
      {
          return QRect(qRound(center.x() - radius - compensation),
                       qRound(center.y() - radius - compensation),
                       qRound((radius + compensation) * 2),
                       qRound((radius + compensation) * 2));

      }

      const int LENS_EXTENT = 10;

      PathDeformRenderer::PathDeformRenderer(QWidget *widget, bool smallScreen)
          : ArthurFrame(widget)
      {
          m_radius = 100;
          m_pos = QPointF(m_radius, m_radius);
          m_direction = QPointF(1, 1);
          m_fontSize = 24;
          m_animated = true;
          m_repaintTimer.start(25, this);
          m_repaintTracker.start();
          m_intensity = 100;
          m_smallScreen = smallScreen;

      //     m_fpsTimer.start(1000, this);
      //     m_fpsCounter = 0;

          generateLensPixmap();
      }

      void PathDeformRenderer::setText(const QString &text)
      {
          m_text = text;

          QFont f("times new roman,utopia");
          f.setStyleStrategy(QFont::ForceOutline);
          f.setPointSize(m_fontSize);
          f.setStyleHint(QFont::Times);

          QFontMetrics fm(f);

          m_paths.clear();
          m_pathBounds = QRect();

          QPointF advance(0, 0);

          bool do_quick = true;
          for (int i=0; i<text.size(); ++i) {
              if (text.at(i).unicode() >= 0x4ff && text.at(i).unicode() <= 0x1e00) {
                  do_quick = false;
                  break;
              }
          }

          if (do_quick) {
              for (int i=0; i<text.size(); ++i) {
                  QPainterPath path;
                  path.addText(advance, f, text.mid(i, 1));
                  m_pathBounds |= path.boundingRect();
                  m_paths << path;
                  advance += QPointF(fm.width(text.mid(i, 1)), 0);
              }
          } else {
              QPainterPath path;
              path.addText(advance, f, text);
              m_pathBounds |= path.boundingRect();
              m_paths << path;
          }

          for (int i=0; i<m_paths.size(); ++i)
              m_paths[i] = m_paths[i] * QMatrix(1, 0, 0, 1, -m_pathBounds.x(), -m_pathBounds.y());

          update();
      }

      void PathDeformRenderer::generateLensPixmap()
      {
          qreal rad = m_radius + LENS_EXTENT;

          QRect bounds = circle_bounds(QPointF(), rad, 0);

          QPainter painter;

          if (preferImage()) {
              m_lens_image = QImage(bounds.size(), QImage::Format_ARGB32_Premultiplied);
              m_lens_image.fill(0);
              painter.begin(&m_lens_image);
          } else {
              m_lens_pixmap = QPixmap(bounds.size());
              m_lens_pixmap.fill(Qt::transparent);
              painter.begin(&m_lens_pixmap);
          }

          QRadialGradient gr(rad, rad, rad, 3 * rad / 5, 3 * rad / 5);
          gr.setColorAt(0.0, QColor(255, 255, 255, 191));
          gr.setColorAt(0.2, QColor(255, 255, 127, 191));
          gr.setColorAt(0.9, QColor(150, 150, 200, 63));
          gr.setColorAt(0.95, QColor(0, 0, 0, 127));
          gr.setColorAt(1, QColor(0, 0, 0, 0));
          painter.setRenderHint(QPainter::Antialiasing);
          painter.setBrush(gr);
          painter.setPen(Qt::NoPen);
          painter.drawEllipse(0, 0, bounds.width(), bounds.height());
      }

      void PathDeformRenderer::setAnimated(bool animated)
      {
          m_animated = animated;

          if (m_animated) {
      //         m_fpsTimer.start(1000, this);
      //         m_fpsCounter = 0;
              m_repaintTimer.start(25, this);
              m_repaintTracker.start();
          } else {
      //         m_fpsTimer.stop();
              m_repaintTimer.stop();
          }
      }

      void PathDeformRenderer::timerEvent(QTimerEvent *e)
      {

          if (e->timerId() == m_repaintTimer.timerId()) {

              if (QLineF(QPointF(0,0), m_direction).length() > 1)
                  m_direction *= 0.995;
              qreal time = m_repaintTracker.restart();

              QRect rectBefore = circle_bounds(m_pos, m_radius, m_fontSize);

              qreal dx = m_direction.x();
              qreal dy = m_direction.y();
              if (time > 0) {
                  dx = dx * time * .1;
                  dy = dy * time * .1;
              }

              m_pos += QPointF(dx, dy);

              if (m_pos.x() - m_radius < 0) {
                  m_direction.setX(-m_direction.x());
                  m_pos.setX(m_radius);
              } else if (m_pos.x() + m_radius > width()) {
                  m_direction.setX(-m_direction.x());
                  m_pos.setX(width() - m_radius);
              }

              if (m_pos.y() - m_radius < 0) {
                  m_direction.setY(-m_direction.y());
                  m_pos.setY(m_radius);
              } else if (m_pos.y() + m_radius > height()) {
                  m_direction.setY(-m_direction.y());
                  m_pos.setY(height() - m_radius);
              }

      #ifdef QT_OPENGL_SUPPORT
              if (usesOpenGL()) {
                  update();
              } else
      #endif
              {
                  QRect rectAfter = circle_bounds(m_pos, m_radius, m_fontSize);
                  update(rectAfter | rectBefore);
              }
          }
      //     else if (e->timerId() == m_fpsTimer.timerId()) {
      //         printf("fps: %d\n", m_fpsCounter);
      //         emit frameRate(m_fpsCounter);
      //         m_fpsCounter = 0;

      //     }
      }

      void PathDeformRenderer::mousePressEvent(QMouseEvent *e)
      {
          setDescriptionEnabled(false);

          m_repaintTimer.stop();
          m_offset = QPointF();
          if (QLineF(m_pos, e->pos()).length() <= m_radius)
              m_offset = m_pos - e->pos();

          m_mousePress = e->pos();

          // If we're not running in small screen mode, always assume we're dragging
          m_mouseDrag = !m_smallScreen;

          mouseMoveEvent(e);
      }

      void PathDeformRenderer::mouseReleaseEvent(QMouseEvent *e)
      {
          if (e->buttons() == Qt::NoButton && m_animated) {
              m_repaintTimer.start(10, this);
              m_repaintTracker.start();
          }

          if (!m_mouseDrag && m_smallScreen)
              emit clicked();
      }

      void PathDeformRenderer::mouseMoveEvent(QMouseEvent *e)
      {
          if (!m_mouseDrag && (QLineF(m_mousePress, e->pos()).length() > 25.0) )
              m_mouseDrag = true;

          if (m_mouseDrag) {
              QRect rectBefore = circle_bounds(m_pos, m_radius, m_fontSize);
              if (e->type() == QEvent::MouseMove) {
                  QLineF line(m_pos, e->pos() + m_offset);
                  line.setLength(line.length() * .1);
                  QPointF dir(line.dx(), line.dy());
                  m_direction = (m_direction + dir) / 2;
              }
              m_pos = e->pos() + m_offset;
      #ifdef QT_OPENGL_SUPPORT
              if (usesOpenGL()) {
                  update();
              } else
      #endif
              {
                  QRect rectAfter = circle_bounds(m_pos, m_radius, m_fontSize);
                  update(rectBefore | rectAfter);
              }
          }
      }

      QPainterPath PathDeformRenderer::lensDeform(const QPainterPath &source, const QPointF &offset)
      {
          QPainterPath path;
          path.addPath(source);

          qreal flip = m_intensity / qreal(100);

          for (int i=0; i<path.elementCount(); ++i) {
              const QPainterPath::Element &e = path.elementAt(i);

              qreal x = e.x + offset.x();
              qreal y = e.y + offset.y();

              qreal dx = x - m_pos.x();
              qreal dy = y - m_pos.y();
              qreal len = m_radius - qSqrt(dx * dx + dy * dy);

              if (len > 0) {
                  path.setElementPositionAt(i,
                                            x + flip * dx * len / m_radius,
                                            y + flip * dy * len / m_radius);
              } else {
                  path.setElementPositionAt(i, x, y);
              }

          }

          return path;
      }

      void PathDeformRenderer::paint(QPainter *painter)
      {
          int pad_x = 5;
          int pad_y = 5;

          int skip_x = qRound(m_pathBounds.width() + pad_x + m_fontSize/2);
          int skip_y = qRound(m_pathBounds.height() + pad_y);

          painter->setPen(Qt::NoPen);
          painter->setBrush(Qt::black);

          QRectF clip(painter->clipPath().boundingRect());

          int overlap = pad_x / 2;

          for (int start_y=0; start_y < height(); start_y += skip_y) {

              if (start_y > clip.bottom())
                  break;

              int start_x = -overlap;
              for (; start_x < width(); start_x += skip_x) {

                  if (start_y + skip_y >= clip.top() &&
                      start_x + skip_x >= clip.left() &&
                      start_x <= clip.right()) {
                      for (int i=0; i<m_paths.size(); ++i) {
                          QPainterPath path = lensDeform(m_paths[i], QPointF(start_x, start_y));
                          painter->drawPath(path);
                      }
                  }
              }
              overlap = skip_x - (start_x - width());

          }

          if (preferImage()) {
              painter->drawImage(m_pos - QPointF(m_radius + LENS_EXTENT, m_radius + LENS_EXTENT),
                                 m_lens_image);
          } else {
              painter->drawPixmap(m_pos - QPointF(m_radius + LENS_EXTENT, m_radius + LENS_EXTENT),
                                  m_lens_pixmap);
          }
      }

      void PathDeformRenderer::setRadius(int radius)
      {
          qreal max = qMax(m_radius, (qreal)radius);
          m_radius = radius;
          generateLensPixmap();
          if (!m_animated || m_radius < max) {
      #ifdef QT_OPENGL_SUPPORT
              if (usesOpenGL()){
                  update();
                  return;
              }
      #endif
              update(circle_bounds(m_pos, max, m_fontSize));
          }
      }

      void PathDeformRenderer::setIntensity(int intensity)
      {
          m_intensity = intensity;
          if (!m_animated) {
      #ifdef QT_OPENGL_SUPPORT
              if (usesOpenGL()) {
                  update();
                  return;
              }
      #endif
              update(circle_bounds(m_pos, m_radius, m_fontSize));
          }
      }