1  // Copyright (c) 2011-2021 The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  4  
  5  #include <qt/qrimagewidget.h>
  6  
  7  #include <qt/guiutil.h>
  8  
  9  #include <QApplication>
 10  #include <QClipboard>
 11  #include <QDrag>
 12  #include <QFontDatabase>
 13  #include <QMenu>
 14  #include <QMimeData>
 15  #include <QMouseEvent>
 16  #include <QPainter>
 17  
 18  #if defined(HAVE_CONFIG_H)
 19  #include <config/bitcoin-config.h> /* for USE_QRCODE */
 20  #endif
 21  
 22  #ifdef USE_QRCODE
 23  #include <qrencode.h>
 24  #endif
 25  
 26  QRImageWidget::QRImageWidget(QWidget* parent)
 27      : QLabel(parent)
 28  {
 29      contextMenu = new QMenu(this);
 30      contextMenu->addAction(tr("&Save Image…"), this, &QRImageWidget::saveImage);
 31      contextMenu->addAction(tr("&Copy Image"), this, &QRImageWidget::copyImage);
 32  }
 33  
 34  bool QRImageWidget::setQR(const QString& data, const QString& text)
 35  {
 36  #ifdef USE_QRCODE
 37      setText("");
 38      if (data.isEmpty()) return false;
 39  
 40      // limit length
 41      if (data.length() > MAX_URI_LENGTH) {
 42          setText(tr("Resulting URI too long, try to reduce the text for label / message."));
 43          return false;
 44      }
 45  
 46      QRcode *code = QRcode_encodeString(data.toUtf8().constData(), 0, QR_ECLEVEL_L, QR_MODE_8, 1);
 47  
 48      if (!code) {
 49          setText(tr("Error encoding URI into QR Code."));
 50          return false;
 51      }
 52  
 53      QImage qrImage = QImage(code->width + 8, code->width + 8, QImage::Format_RGB32);
 54      qrImage.fill(0xffffff);
 55      unsigned char *p = code->data;
 56      for (int y = 0; y < code->width; ++y) {
 57          for (int x = 0; x < code->width; ++x) {
 58              qrImage.setPixel(x + 4, y + 4, ((*p & 1) ? 0x0 : 0xffffff));
 59              ++p;
 60          }
 61      }
 62      QRcode_free(code);
 63  
 64      const int qr_image_size = QR_IMAGE_SIZE + (text.isEmpty() ? 0 : 2 * QR_IMAGE_MARGIN);
 65      QImage qrAddrImage(qr_image_size, qr_image_size, QImage::Format_RGB32);
 66      qrAddrImage.fill(0xffffff);
 67      {
 68          QPainter painter(&qrAddrImage);
 69          painter.drawImage(QR_IMAGE_MARGIN, 0, qrImage.scaled(QR_IMAGE_SIZE, QR_IMAGE_SIZE));
 70  
 71          if (!text.isEmpty()) {
 72              QRect paddedRect = qrAddrImage.rect();
 73              paddedRect.setHeight(QR_IMAGE_SIZE + QR_IMAGE_TEXT_MARGIN);
 74  
 75              QFont font = GUIUtil::fixedPitchFont();
 76              font.setStretch(QFont::SemiCondensed);
 77              font.setLetterSpacing(QFont::AbsoluteSpacing, 1);
 78              const qreal font_size = GUIUtil::calculateIdealFontSize(paddedRect.width() - 2 * QR_IMAGE_TEXT_MARGIN, text, font);
 79              font.setPointSizeF(font_size);
 80  
 81              painter.setFont(font);
 82              painter.drawText(paddedRect, Qt::AlignBottom | Qt::AlignCenter, text);
 83          }
 84      }
 85  
 86      setPixmap(QPixmap::fromImage(qrAddrImage));
 87  
 88      return true;
 89  #else
 90      setText(tr("QR code support not available."));
 91      return false;
 92  #endif
 93  }
 94  
 95  QImage QRImageWidget::exportImage()
 96  {
 97      return GUIUtil::GetImage(this);
 98  }
 99  
100  void QRImageWidget::mousePressEvent(QMouseEvent *event)
101  {
102      if (event->button() == Qt::LeftButton && GUIUtil::HasPixmap(this)) {
103          event->accept();
104          QMimeData *mimeData = new QMimeData;
105          mimeData->setImageData(exportImage());
106  
107          QDrag *drag = new QDrag(this);
108          drag->setMimeData(mimeData);
109          drag->exec();
110      } else {
111          QLabel::mousePressEvent(event);
112      }
113  }
114  
115  void QRImageWidget::saveImage()
116  {
117      if (!GUIUtil::HasPixmap(this))
118          return;
119      QString fn = GUIUtil::getSaveFileName(
120          this, tr("Save QR Code"), QString(),
121          /*: Expanded name of the PNG file format.
122              See: https://en.wikipedia.org/wiki/Portable_Network_Graphics. */
123          tr("PNG Image") + QLatin1String(" (*.png)"), nullptr);
124      if (!fn.isEmpty())
125      {
126          exportImage().save(fn);
127      }
128  }
129  
130  void QRImageWidget::copyImage()
131  {
132      if (!GUIUtil::HasPixmap(this))
133          return;
134      QApplication::clipboard()->setImage(exportImage());
135  }
136  
137  void QRImageWidget::contextMenuEvent(QContextMenuEvent *event)
138  {
139      if (!GUIUtil::HasPixmap(this))
140          return;
141      contextMenu->exec(event->globalPos());
142  }