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pathdeform.cpp Example File
demos/deform/pathdeform.cpp

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 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
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 ** General Public License version 2.1 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPL included in the
 ** packaging of this file.  Please review the following information to
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 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 3.0 as published by the Free Software
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 ** packaging of this file.  Please review the following information to
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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, SLOT(emitQuitSignal()));
     connect(okButton, SIGNAL(clicked()), this, SLOT(emitOkSignal()));
     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"));
 }

 void PathDeformControls::emitQuitSignal()
 {   emit quitPressed();  }

 void PathDeformControls::emitOkSignal()
 {   emit okPressed();   }

 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)
     {
         m_controls->setStyle(style);

         QList<QWidget *> widgets = qFindChildren<QWidget *>(m_controls);
         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);
             QApplication::syncX();
         }
     }
 //     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();
         } else
 #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();
         } else
 #endif
         {
             update(circle_bounds(m_pos, m_radius, m_fontSize));
         }
     }
 }