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#include <QtGui>

#include <math.h>

#include "tabletcanvas.h"

//! [0]

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;

}

//! [0]

//! [1]

bool TabletCanvas::saveImage(const QString &file)

{

    return image.save(file);

}

//! [1]

//! [2]

bool TabletCanvas::loadImage(const QString &file)

{

    bool success = image.load(file);

    if (success) {

        update();

        return true;

    }

    return false;

}

//! [2]

//! [3]

void TabletCanvas::tabletEvent(QTabletEvent *event)

{

    switch (event->type()) {

        case QEvent::TabletPress:

            if (!deviceDown) {

                deviceDown = true;

                polyLine[0] = polyLine[1] = polyLine[2] = event->pos();

            }

            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();

}

//! [3]

//! [4]

void TabletCanvas::paintEvent(QPaintEvent *)

{

    QPainter painter(this);

    painter.drawImage(QPoint(0, 0), image);

}

//! [4]

//! [5]

void TabletCanvas::paintImage(QPainter &painter, QTabletEvent *event)

{

    QPoint brushAdjust(10, 10);

    switch (myTabletDevice) {

        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:

            {

                const QString error(tr("This input device is not supported by the example."));

#ifndef QT_NO_STATUSTIP

                QStatusTipEvent status(error);

                QApplication::sendEvent(this, &status);

#else

                qWarning() << error;

#endif

            }

            break;

        default:

            {

                const QString error(tr("Unknown tablet device - treating as stylus"));

#ifndef QT_NO_STATUSTIP

                QStatusTipEvent status(error);

                QApplication::sendEvent(this, &status);

#else

                qWarning() << error;

#endif

            }

            // FALL-THROUGH

        case QTabletEvent::Stylus:

            painter.setBrush(myBrush);

            painter.setPen(myPen);

            painter.drawLine(polyLine[1], event->pos());

            break;

    }

}

//! [5]

//! [6]

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;

    }

}

//! [6]

//! [7]

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);

//! [7] //! [8]

    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);

    }

//! [8] //! [9]

    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:

            ;

    }

//! [9] //! [10]

    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);

    }

//! [10] //! [11]

    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);

    }

}

//! [11]

void TabletCanvas::resizeEvent(QResizeEvent *)

{

    initImage();

    polyLine[0] = polyLine[1] = polyLine[2] = QPoint();

}