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#include <QtGui>

#include "imagecomposer.h"

//! [0]

static const QSize resultSize(200, 200);

//! [0]

//! [1]

ImageComposer::ImageComposer()

{

    sourceButton = new QToolButton;

    sourceButton->setIconSize(resultSize);

    operatorComboBox = new QComboBox;

    addOp(QPainter::CompositionMode_SourceOver, tr("SourceOver"));

    addOp(QPainter::CompositionMode_DestinationOver, tr("DestinationOver"));

    addOp(QPainter::CompositionMode_Clear, tr("Clear"));

    addOp(QPainter::CompositionMode_Source, tr("Source"));

    addOp(QPainter::CompositionMode_Destination, tr("Destination"));

    addOp(QPainter::CompositionMode_SourceIn, tr("SourceIn"));

    addOp(QPainter::CompositionMode_DestinationIn, tr("DestinationIn"));

    addOp(QPainter::CompositionMode_SourceOut, tr("SourceOut"));

    addOp(QPainter::CompositionMode_DestinationOut, tr("DestinationOut"));

    addOp(QPainter::CompositionMode_SourceAtop, tr("SourceAtop"));

    addOp(QPainter::CompositionMode_DestinationAtop, tr("DestinationAtop"));

    addOp(QPainter::CompositionMode_Xor, tr("Xor"));

    addOp(QPainter::CompositionMode_Plus, tr("Plus"));

    addOp(QPainter::CompositionMode_Multiply, tr("Multiply"));

    addOp(QPainter::CompositionMode_Screen, tr("Screen"));

    addOp(QPainter::CompositionMode_Overlay, tr("Overlay"));

    addOp(QPainter::CompositionMode_Darken, tr("Darken"));

    addOp(QPainter::CompositionMode_Lighten, tr("Lighten"));

    addOp(QPainter::CompositionMode_ColorDodge, tr("ColorDodge"));

    addOp(QPainter::CompositionMode_ColorBurn, tr("ColorBurn"));

    addOp(QPainter::CompositionMode_HardLight, tr("HardLight"));

    addOp(QPainter::CompositionMode_SoftLight, tr("SoftLight"));

    addOp(QPainter::CompositionMode_Difference, tr("Difference"));

    addOp(QPainter::CompositionMode_Exclusion, tr("Exclusion"));

//! [1]

//! [2]

    destinationButton = new QToolButton;

    destinationButton->setIconSize(resultSize);

    equalLabel = new QLabel(tr("="));

    resultLabel = new QLabel;

    resultLabel->setMinimumWidth(resultSize.width());

//! [2]

//! [3]

    connect(sourceButton, SIGNAL(clicked()), this, SLOT(chooseSource()));

    connect(operatorComboBox, SIGNAL(activated(int)),

            this, SLOT(recalculateResult()));

    connect(destinationButton, SIGNAL(clicked()),

            this, SLOT(chooseDestination()));

//! [3]

//! [4]

    QGridLayout *mainLayout = new QGridLayout;

    mainLayout->addWidget(sourceButton, 0, 0, 3, 1);

    mainLayout->addWidget(operatorComboBox, 1, 1);

    mainLayout->addWidget(destinationButton, 0, 2, 3, 1);

    mainLayout->addWidget(equalLabel, 1, 3);

    mainLayout->addWidget(resultLabel, 0, 4, 3, 1);

    mainLayout->setSizeConstraint(QLayout::SetFixedSize);

    setLayout(mainLayout);

//! [4]

//! [5]

    resultImage = QImage(resultSize, QImage::Format_ARGB32_Premultiplied);

    loadImage(":/images/butterfly.png", &sourceImage, sourceButton);

    loadImage(":/images/checker.png", &destinationImage, destinationButton);

    setWindowTitle(tr("Image Composition"));

}

//! [5]

//! [6]

void ImageComposer::chooseSource()

{

    chooseImage(tr("Choose Source Image"), &sourceImage, sourceButton);

}

//! [6]

//! [7]

void ImageComposer::chooseDestination()

{

    chooseImage(tr("Choose Destination Image"), &destinationImage,

                destinationButton);

}

//! [7]

//! [8]

void ImageComposer::recalculateResult()

{

    QPainter::CompositionMode mode = currentMode();

    QPainter painter(&resultImage);

    painter.setCompositionMode(QPainter::CompositionMode_Source);

    painter.fillRect(resultImage.rect(), Qt::transparent);

    painter.setCompositionMode(QPainter::CompositionMode_SourceOver);

    painter.drawImage(0, 0, destinationImage);

    painter.setCompositionMode(mode);

    painter.drawImage(0, 0, sourceImage);

    painter.setCompositionMode(QPainter::CompositionMode_DestinationOver);

    painter.fillRect(resultImage.rect(), Qt::white);

    painter.end();

    resultLabel->setPixmap(QPixmap::fromImage(resultImage));

}

//! [8]

//! [9]

void ImageComposer::addOp(QPainter::CompositionMode mode, const QString &name)

{

    operatorComboBox->addItem(name, mode);

}

//! [9]

//! [10]

void ImageComposer::chooseImage(const QString &title, QImage *image,

                                QToolButton *button)

{

    QString fileName = QFileDialog::getOpenFileName(this, title);

    if (!fileName.isEmpty())

        loadImage(fileName, image, button);

}

//! [10]

//! [11]

void ImageComposer::loadImage(const QString &fileName, QImage *image,

                              QToolButton *button)

{

    image->load(fileName);

    QImage fixedImage(resultSize, QImage::Format_ARGB32_Premultiplied);

    QPainter painter(&fixedImage);

    painter.setCompositionMode(QPainter::CompositionMode_Source);

    painter.fillRect(fixedImage.rect(), Qt::transparent);

    painter.setCompositionMode(QPainter::CompositionMode_SourceOver);

    painter.drawImage(imagePos(*image), *image);

    painter.end();

    button->setIcon(QPixmap::fromImage(fixedImage));

    *image = fixedImage;

    recalculateResult();

}

//! [11]

//! [12]

QPainter::CompositionMode ImageComposer::currentMode() const

{

    return (QPainter::CompositionMode)

           operatorComboBox->itemData(operatorComboBox->currentIndex()).toInt();

}

//! [12]

//! [13]

QPoint ImageComposer::imagePos(const QImage &image) const

{

    return QPoint((resultSize.width() - image.width()) / 2,

                  (resultSize.height() - image.height()) / 2);

}

//! [13]