Просмотр исходного текста страницы C++/Qt/QTabletEvent

==Tablet widget==


   
<source lang="cpp">  
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#ifndef TABLETCANVAS_H
#define TABLETCANVAS_H
#include <QWidget>
#include <QImage>
#include <QPoint>
#include <QTabletEvent>
#include <QColor>
#include <QBrush>
#include <QPen>
#include <QPoint>
QT_BEGIN_NAMESPACE
class QPaintEvent;
class QString;
QT_END_NAMESPACE

class TabletCanvas : public QWidget
{
    Q_OBJECT
public:
    enum AlphaChannelType { AlphaPressure, AlphaTilt, NoAlpha };
    enum ColorSaturationType { SaturationVTilt, SaturationHTilt,
                               SaturationPressure, NoSaturation };
    enum LineWidthType { LineWidthPressure, LineWidthTilt, NoLineWidth };
    TabletCanvas();
    bool saveImage(const QString &file);
    bool loadImage(const QString &file);
    void setAlphaChannelType(AlphaChannelType type)
        { alphaChannelType = type; }
    void setColorSaturationType(ColorSaturationType type)
        { colorSaturationType = type; }
    void setLineWidthType(LineWidthType type)
        { lineWidthType = type; }
    void setColor(const QColor &color)
        { myColor = color; }
    QColor color() const
        { return myColor; }
    void setTabletDevice(QTabletEvent::TabletDevice device)
        { myTabletDevice = device; }
    int maximum(int a, int b)
        { return a > b ? a : b; }
protected:
    void tabletEvent(QTabletEvent *event);
    void paintEvent(QPaintEvent *event);
    void resizeEvent(QResizeEvent *event);
private:
    void initImage();
    void paintImage(QPainter &painter, QTabletEvent *event);
    Qt::BrushStyle brushPattern(qreal value);
    void updateBrush(QTabletEvent *event);
    AlphaChannelType alphaChannelType;
    ColorSaturationType colorSaturationType;
    LineWidthType lineWidthType;
    QTabletEvent::PointerType pointerType;
    QTabletEvent::TabletDevice myTabletDevice;
    QColor myColor;
    QImage image;
    QBrush myBrush;
    QPen myPen;
    bool deviceDown;
    QPoint polyLine[3];
};

#endif



#include <QtGui>
#include <math.h>
#include "tabletcanvas.h"

TabletCanvas::TabletCanvas()
{
    resize(500, 500);
    myBrush = QBrush();
    myPen = QPen();
    initImage();
    setAutoFillBackground(true);
    deviceDown = false;
    myColor = Qt::red;
    myTabletDevice = QTabletEvent::Stylus;
    alphaChannelType = NoAlpha;
    colorSaturationType = NoSaturation;
    lineWidthType = LineWidthPressure;
}
void TabletCanvas::initImage()
{
    QImage newImage = QImage(width(), height(), QImage::Format_ARGB32);
    QPainter painter(&newImage);
    painter.fillRect(0, 0, newImage.width(), newImage.height(), Qt::white);
    if (!image.isNull())
        painter.drawImage(0, 0, image);
    painter.end();
    image = newImage;
}

bool TabletCanvas::saveImage(const QString &file)
{
    return image.save(file);
}

bool TabletCanvas::loadImage(const QString &file)
{
    bool success = image.load(file);
    if (success) {
        update();
        return true;
    }
    return false;
}

void TabletCanvas::tabletEvent(QTabletEvent *event)
{
    switch (event->type()) {
        case QEvent::TabletPress:
            if (!deviceDown)
                deviceDown = true;
            break;
        case QEvent::TabletRelease:
            if (deviceDown)
                deviceDown = false;
            break;
        case QEvent::TabletMove:
            polyLine[2] = polyLine[1];
            polyLine[1] = polyLine[0];
            polyLine[0] = event->pos();
            if (deviceDown) {
                updateBrush(event);
                QPainter painter(&image);
                paintImage(painter, event);
            }
            break;
        default:
            break;
    }
    update();
}

void TabletCanvas::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.drawImage(QPoint(0, 0), image);
}

void TabletCanvas::paintImage(QPainter &painter, QTabletEvent *event)
{
    QPoint brushAdjust(10, 10);
    switch (myTabletDevice) {
        case QTabletEvent::Stylus:
            painter.setBrush(myBrush);
            painter.setPen(myPen);
            painter.drawLine(polyLine[1], event->pos());
            break;
        case QTabletEvent::Airbrush:
            myBrush.setColor(myColor);
            myBrush.setStyle(brushPattern(event->pressure()));
            painter.setPen(Qt::NoPen);
            painter.setBrush(myBrush);
            for (int i = 0; i < 3; ++i) {
                painter.drawEllipse(QRect(polyLine[i] - brushAdjust,
                                    polyLine[i] + brushAdjust));
            }
            break;
        case QTabletEvent::Puck:
        case QTabletEvent::FourDMouse:
        case QTabletEvent::RotationStylus:
            qWarning("This input device is not supported by the example.");
            break;
        default:
            qWarning("Unknown tablet device.");
    }
}

Qt::BrushStyle TabletCanvas::brushPattern(qreal value)
{
    int pattern = int((value) * 100.0) % 7;
    switch (pattern) {
        case 0:
            return Qt::SolidPattern;
        case 1:
            return Qt::Dense1Pattern;
        case 2:
            return Qt::Dense2Pattern;
        case 3:
            return Qt::Dense3Pattern;
        case 4:
            return Qt::Dense4Pattern;
        case 5:
            return Qt::Dense5Pattern;
        case 6:
            return Qt::Dense6Pattern;
        default:
            return Qt::Dense7Pattern;
    }
}

void TabletCanvas::updateBrush(QTabletEvent *event)
{
    int hue, saturation, value, alpha;
    myColor.getHsv(&hue, &saturation, &value, &alpha);
    int vValue = int(((event->yTilt() + 60.0) / 120.0) * 255);
    int hValue = int(((event->xTilt() + 60.0) / 120.0) * 255);
 
    switch (alphaChannelType) {
        case AlphaPressure:
            myColor.setAlpha(int(event->pressure() * 255.0));
            break;
        case AlphaTilt:
            myColor.setAlpha(maximum(abs(vValue - 127), abs(hValue - 127)));
            break;
        default:
            myColor.setAlpha(255);
    }
 
    switch (colorSaturationType) {
        case SaturationVTilt:
            myColor.setHsv(hue, vValue, value, alpha);
            break;
        case SaturationHTilt:
            myColor.setHsv(hue, hValue, value, alpha);
            break;
        case SaturationPressure:
            myColor.setHsv(hue, int(event->pressure() * 255.0), value, alpha);
            break;
        default:
            ;
    }
 
    switch (lineWidthType) {
        case LineWidthPressure:
            myPen.setWidthF(event->pressure() * 10 + 1);
            break;
        case LineWidthTilt:
            myPen.setWidthF(maximum(abs(vValue - 127), abs(hValue - 127)) / 12);
            break;
        default:
            myPen.setWidthF(1);
    }
 
    if (event->pointerType() == QTabletEvent::Eraser) {
        myBrush.setColor(Qt::white);
        myPen.setColor(Qt::white);
        myPen.setWidthF(event->pressure() * 10 + 1);
    } else {
        myBrush.setColor(myColor);
        myPen.setColor(myColor);
    }
}

void TabletCanvas::resizeEvent(QResizeEvent *event)
{
    initImage();
    polyLine[0] = polyLine[1] = polyLine[2] = QPoint();
}



#ifndef TABLETAPPLICATION_H
#define TABLETAPPLICATION_H
#include <QApplication>
#include "tabletcanvas.h"

class TabletApplication : public QApplication
{
    Q_OBJECT
public:
    TabletApplication(int &argv, char **args)
    : QApplication(argv, args) {}
    bool event(QEvent *event);
    void setCanvas(TabletCanvas *canvas)
        { myCanvas = canvas; }
private:
    TabletCanvas *myCanvas;
};

#endif


#include <QtGui>
#include "tabletapplication.h"

bool TabletApplication::event(QEvent *event)
{
    if (event->type() == QEvent::TabletEnterProximity ||
        event->type() == QEvent::TabletLeaveProximity) {
        myCanvas->setTabletDevice(
            static_cast<QTabletEvent *>(event)->device());
        return true;
    }
    return QApplication::event(event);
}



#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
QT_BEGIN_NAMESPACE
class QAction;
class QActionGroup;
class QMenu;
class QStatusBar;
QT_END_NAMESPACE
class TabletCanvas;

class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow(TabletCanvas *canvas);
private slots:
    void brushColorAct();
    void alphaActionTriggered(QAction *action);
    void lineWidthActionTriggered(QAction *action);
    void saturationActionTriggered(QAction *action);
    void saveAct();
    void loadAct();
    void aboutAct();
private:
    void createActions();
    void createMenus();
    TabletCanvas *myCanvas;
    QAction *brushColorAction;
    QActionGroup *brushActionGroup;
    QActionGroup *alphaChannelGroup;
    QAction *alphaChannelPressureAction;
    QAction *alphaChannelTiltAction;
    QAction *noAlphaChannelAction;
    QActionGroup *colorSaturationGroup;
    QAction *colorSaturationVTiltAction;
    QAction *colorSaturationHTiltAction;
    QAction *colorSaturationPressureAction;
    QAction *noColorSaturationAction;
    QActionGroup *lineWidthGroup;
    QAction *lineWidthPressureAction;
    QAction *lineWidthTiltAction;
    QAction *lineWidthFixedAction;
    QAction *exitAction;
    QAction *saveAction;
    QAction *loadAction;
    QAction *aboutAction;
    QAction *aboutQtAction;
    QMenu *fileMenu;
    QMenu *brushMenu;
    QMenu *tabletMenu;
    QMenu *helpMenu;
    QMenu *colorSaturationMenu;
    QMenu *lineWidthMenu;
    QMenu *alphaChannelMenu;
};

#endif


#include <QtGui>
#include "mainwindow.h"
#include "tabletcanvas.h"

MainWindow::MainWindow(TabletCanvas *canvas)
{
    myCanvas = canvas;
    createActions();
    createMenus();
    myCanvas->setColor(Qt::red);
    myCanvas->setLineWidthType(TabletCanvas::LineWidthPressure);
    myCanvas->setAlphaChannelType(TabletCanvas::NoAlpha);
    myCanvas->setColorSaturationType(TabletCanvas::NoSaturation);
    setWindowTitle(tr("Tablet Example"));
    setCentralWidget(myCanvas);
}

void MainWindow::brushColorAct()
{
    QColor color = QColorDialog::getColor(myCanvas->color());
    if (color.isValid())
        myCanvas->setColor(color);
}

void MainWindow::alphaActionTriggered(QAction *action)
{
    if (action == alphaChannelPressureAction) {
        myCanvas->setAlphaChannelType(TabletCanvas::AlphaPressure);
    } else if (action == alphaChannelTiltAction) {
        myCanvas->setAlphaChannelType(TabletCanvas::AlphaTilt);
    } else {
        myCanvas->setAlphaChannelType(TabletCanvas::NoAlpha);
    }
}

void MainWindow::lineWidthActionTriggered(QAction *action)
{
    if (action == lineWidthPressureAction) {
        myCanvas->setLineWidthType(TabletCanvas::LineWidthPressure);
    } else if (action == lineWidthTiltAction) {
        myCanvas->setLineWidthType(TabletCanvas::LineWidthTilt);
    } else {
        myCanvas->setLineWidthType(TabletCanvas::NoLineWidth);
    }
}

void MainWindow::saturationActionTriggered(QAction *action)
{
    if (action == colorSaturationVTiltAction) {
        myCanvas->setColorSaturationType(TabletCanvas::SaturationVTilt);
    } else if (action == colorSaturationHTiltAction) {
        myCanvas->setColorSaturationType(TabletCanvas::SaturationHTilt);
    } else if (action == colorSaturationPressureAction) {
        myCanvas->setColorSaturationType(TabletCanvas::SaturationPressure);
    } else {
        myCanvas->setColorSaturationType(TabletCanvas::NoSaturation);
    }
}

void MainWindow::saveAct()
{
    QString path = QDir::currentPath() + "/untitled.png";
    QString fileName = QFileDialog::getSaveFileName(this, tr("Save Picture"),
                             path);
    if (!myCanvas->saveImage(fileName))
        QMessageBox::information(this, "Error Saving Picture",
                                 "Could not save the image");
}

void MainWindow::loadAct()
{
    QString fileName = QFileDialog::getOpenFileName(this, tr("Open Picture"),
                                                    QDir::currentPath());
    if (!myCanvas->loadImage(fileName))
        QMessageBox::information(this, "Error Opening Picture",
                                 "Could not open picture");
}

void MainWindow::aboutAct()
{
    QMessageBox::about(this, tr("About Tablet Example"),
                       tr("This example shows use of a Wacom tablet in Qt"));
}

void MainWindow::createActions()
{
    brushColorAction = new QAction(tr("&Brush Color..."), this);
    brushColorAction->setShortcut(tr("Ctrl+C"));
    connect(brushColorAction, SIGNAL(triggered()),
            this, SLOT(brushColorAct()));

    alphaChannelPressureAction = new QAction(tr("&Pressure"), this);
    alphaChannelPressureAction->setCheckable(true);
    alphaChannelTiltAction = new QAction(tr("&Tilt"), this);
    alphaChannelTiltAction->setCheckable(true);
    noAlphaChannelAction = new QAction(tr("No Alpha Channel"), this);
    noAlphaChannelAction->setCheckable(true);
    noAlphaChannelAction->setChecked(true);
    alphaChannelGroup = new QActionGroup(this);
    alphaChannelGroup->addAction(alphaChannelPressureAction);
    alphaChannelGroup->addAction(alphaChannelTiltAction);
    alphaChannelGroup->addAction(noAlphaChannelAction);
    connect(alphaChannelGroup, SIGNAL(triggered(QAction *)),
            this, SLOT(alphaActionTriggered(QAction *)));

    colorSaturationVTiltAction = new QAction(tr("&Vertical Tilt"), this);
    colorSaturationVTiltAction->setCheckable(true);
    colorSaturationHTiltAction = new QAction(tr("&Horizontal Tilt"), this);
    colorSaturationHTiltAction->setCheckable(true);
    colorSaturationPressureAction = new QAction(tr("&Pressure"), this);
    colorSaturationPressureAction->setCheckable(true);
    noColorSaturationAction = new QAction(tr("&No Color Saturation"), this);
    noColorSaturationAction->setCheckable(true);
    noColorSaturationAction->setChecked(true);
    colorSaturationGroup = new QActionGroup(this);
    colorSaturationGroup->addAction(colorSaturationVTiltAction);
    colorSaturationGroup->addAction(colorSaturationHTiltAction);
    colorSaturationGroup->addAction(colorSaturationPressureAction);
    colorSaturationGroup->addAction(noColorSaturationAction);
    connect(colorSaturationGroup, SIGNAL(triggered(QAction *)),
            this, SLOT(saturationActionTriggered(QAction *)));
    lineWidthPressureAction = new QAction(tr("&Pressure"), this);
    lineWidthPressureAction->setCheckable(true);
    lineWidthPressureAction->setChecked(true);
    lineWidthTiltAction = new QAction(tr("&Tilt"), this);
    lineWidthTiltAction->setCheckable(true);
    lineWidthFixedAction = new QAction(tr("&Fixed"), this);
    lineWidthFixedAction->setCheckable(true);
    lineWidthGroup = new QActionGroup(this);
    lineWidthGroup->addAction(lineWidthPressureAction);
    lineWidthGroup->addAction(lineWidthTiltAction);
    lineWidthGroup->addAction(lineWidthFixedAction);
    connect(lineWidthGroup, SIGNAL(triggered(QAction *)),
            this, SLOT(lineWidthActionTriggered(QAction *)));
    exitAction = new QAction(tr("E&xit"), this);
    exitAction->setShortcut(tr("Ctrl+X"));
    connect(exitAction, SIGNAL(triggered()),
            this, SLOT(close()));
    loadAction = new QAction(tr("&Open..."), this);
    loadAction->setShortcut(tr("Ctrl+O"));
    connect(loadAction, SIGNAL(triggered()),
            this, SLOT(loadAct()));
    saveAction = new QAction(tr("&Save As..."), this);
    saveAction->setShortcut(tr("Ctrl+S"));
    connect(saveAction, SIGNAL(triggered()),
            this, SLOT(saveAct()));
    aboutAction = new QAction(tr("A&bout"), this);
    aboutAction->setShortcut(tr("Ctrl+B"));
    connect(aboutAction, SIGNAL(triggered()),
            this, SLOT(aboutAct()));
    aboutQtAction = new QAction(tr("About &Qt"), this);
    aboutQtAction->setShortcut(tr("Ctrl+Q"));
    connect(aboutQtAction, SIGNAL(triggered()),
            qApp, SLOT(aboutQt()));
}

void MainWindow::createMenus()
{
    fileMenu = menuBar()->addMenu(tr("&File"));
    fileMenu->addAction(loadAction);
    fileMenu->addAction(saveAction);
    fileMenu->addSeparator();
    fileMenu->addAction(exitAction);
    brushMenu = menuBar()->addMenu(tr("&Brush"));
    brushMenu->addAction(brushColorAction);
    tabletMenu = menuBar()->addMenu(tr("&Tablet"));
    lineWidthMenu = tabletMenu->addMenu(tr("&Line Width"));
    lineWidthMenu->addAction(lineWidthPressureAction);
    lineWidthMenu->addAction(lineWidthTiltAction);
    lineWidthMenu->addAction(lineWidthFixedAction);
    alphaChannelMenu = tabletMenu->addMenu(tr("&Alpha Channel"));
    alphaChannelMenu->addAction(alphaChannelPressureAction);
    alphaChannelMenu->addAction(alphaChannelTiltAction);
    alphaChannelMenu->addAction(noAlphaChannelAction);
    colorSaturationMenu = tabletMenu->addMenu(tr("&Color Saturation"));
    colorSaturationMenu->addAction(colorSaturationVTiltAction);
    colorSaturationMenu->addAction(colorSaturationHTiltAction);
    colorSaturationMenu->addAction(noColorSaturationAction);
    helpMenu = menuBar()->addMenu("&Help");
    helpMenu->addAction(aboutAction);
    helpMenu->addAction(aboutQtAction);
}



#include <QtGui>
#include "mainwindow.h"
#include "tabletapplication.h"
#include "tabletcanvas.h"

int main(int argv, char *args[])
{
    TabletApplication app(argv, args);
    TabletCanvas *canvas = new TabletCanvas;
    app.setCanvas(canvas);
    MainWindow mainWindow(canvas);
    mainWindow.resize(500, 500);
    mainWindow.show();
    return app.exec();
}
   
    
  </source>