qrimagewidget.cpp

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// Copyright (c) 2011-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#include <qt/qrimagewidget.h>
 
#include <qt/guiutil.h>
 
#include <QApplication>
#include <QClipboard>
#include <QDrag>
#include <QMenu>
#include <QMimeData>
#include <QMouseEvent>
#include <QPainter>
 
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h> /* for USE_QRCODE */
#endif
 
#ifdef USE_QRCODE
#include <qrencode.h>
#endif
 
QRImageWidget::QRImageWidget(QWidget *parent)
    : QLabel(parent), contextMenu(nullptr) {
    contextMenu = new QMenu(this);
    QAction *saveImageAction = new QAction(tr("&Save Image..."), this);
    connect(saveImageAction, &QAction::triggered, this,
            &QRImageWidget::saveImage);
    contextMenu->addAction(saveImageAction);
    QAction *copyImageAction = new QAction(tr("&Copy Image"), this);
    connect(copyImageAction, &QAction::triggered, this,
            &QRImageWidget::copyImage);
    contextMenu->addAction(copyImageAction);
}
 
bool QRImageWidget::hasPixmap() const {
#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
    return !pixmap(Qt::ReturnByValue).isNull();
#else
    return pixmap() != nullptr;
#endif
}
 
bool QRImageWidget::setQR(const QString &qrData, const QString &text) {
#ifdef USE_QRCODE
    setText("");
    if (qrData.isEmpty()) {
        return false;
    }
 
    // limit length
    if (qrData.length() > MAX_URI_LENGTH) {
        setText(tr("Resulting URI too long, try to reduce the text for label / "
                   "message."));
        return false;
    }
 
    QRcode *code = QRcode_encodeString(qrData.toUtf8().constData(), 0,
                                       QR_ECLEVEL_L, QR_MODE_8, 1);
 
    if (!code) {
        setText(tr("Error encoding URI into QR Code."));
        return false;
    }
 
    QImage qrImage =
        QImage(code->width + 8, code->width + 8, QImage::Format_RGB32);
    qrImage.fill(0xffffff);
    uint8_t *p = code->data;
    for (int y = 0; y < code->width; ++y) {
        for (int x = 0; x < code->width; ++x) {
            qrImage.setPixel(x + 4, y + 4, ((*p & 1) ? 0x0 : 0xffffff));
            ++p;
        }
    }
    QRcode_free(code);
 
    QImage qrAddrImage =
        QImage(QR_IMAGE_SIZE, QR_IMAGE_SIZE + (text.isEmpty() ? 0 : 20),
               QImage::Format_RGB32);
    qrAddrImage.fill(0xffffff);
    QPainter painter(&qrAddrImage);
    painter.drawImage(0, 0, qrImage.scaled(QR_IMAGE_SIZE, QR_IMAGE_SIZE));
 
    if (!text.isEmpty()) {
        QFont font = GUIUtil::fixedPitchFont();
        QRect paddedRect = qrAddrImage.rect();
 
        // calculate ideal font size
        qreal font_size = GUIUtil::calculateIdealFontSize(
            paddedRect.width() - 20, text, font);
        font.setPointSizeF(font_size);
 
        painter.setFont(font);
        paddedRect.setHeight(QR_IMAGE_SIZE + 12);
        painter.drawText(paddedRect, Qt::AlignBottom | Qt::AlignCenter, text);
    }
 
    painter.end();
    setPixmap(QPixmap::fromImage(qrAddrImage));
 
    return true;
#else
    setText(tr("QR code support not available."));
    return false;
#endif
}
 
QImage QRImageWidget::exportImage() {
#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
    return pixmap(Qt::ReturnByValue).toImage();
#else
    return hasPixmap() ? pixmap()->toImage() : QImage();
#endif
}
 
void QRImageWidget::mousePressEvent(QMouseEvent *event) {
    if (event->button() == Qt::LeftButton && hasPixmap()) {
        event->accept();
        QMimeData *mimeData = new QMimeData;
        mimeData->setImageData(exportImage());
 
        QDrag *drag = new QDrag(this);
        drag->setMimeData(mimeData);
        drag->exec();
    } else {
        QLabel::mousePressEvent(event);
    }
}
 
void QRImageWidget::saveImage() {
    if (!hasPixmap()) {
        return;
    }
    QString fn = GUIUtil::getSaveFileName(this, tr("Save QR Code"), QString(),
                                          tr("PNG Image (*.png)"), nullptr);
    if (!fn.isEmpty()) {
        exportImage().save(fn);
    }
}
 
void QRImageWidget::copyImage() {
    if (!hasPixmap()) {
        return;
    }
    QApplication::clipboard()->setImage(exportImage());
}
 
void QRImageWidget::contextMenuEvent(QContextMenuEvent *event) {
    if (!hasPixmap()) {
        return;
    }
    contextMenu->exec(event->globalPos());
}