pathdeform.cpp Example File

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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));
      }
  }