qrcode support by html tooltip

src/misc/qrwidget.cpp

@@ -0,0 +1,87 @@
+#include "qrwidget.h"
+#include <QPainter>
+#include <QDebug>
+#include <QBuffer>
+#include <QImage>
+#include "qrcodewindow.h"
+#include "qrencode.h"
+
+QRWidget::QRWidget(QWidget *parent) : QWidget(parent), data("0")
+//Note: The encoding fails with empty string so I just default to something else. Use the setQRData() call to change this.
+{
+    //size of the qimage might be problematic in the future, but it works for me
+    size.setWidth(480);
+    size.setHeight(480);
+    image = new QImage(size, QImage::Format_RGB32);
+}
+
+void QRWidget::setQRData(QString data)
+{
+    this->data = data;
+    paintImage();    
+}
+
+QString QRWidget::getImageAsText()
+{
+    paintImage();
+ 	QByteArray ba;
+ 	QBuffer buffer(&ba);
+ 	buffer.open(QIODevice::WriteOnly);
+    image->save(&buffer, "PNG"); // writes the image in PNG format inside the buffer
+    
+    QString iconBase64 = QString::fromLatin1(ba.toBase64().data());
+    QString base64Image  = "<img width=\"350\" heigth=\"350\" src=\"data:image/png;base64," + iconBase64 +"\" />";
+    
+ 	return QString(base64Image);
+}
+
+//http://stackoverflow.com/questions/21400254/how-to-draw-a-qr-code-with-qt-in-native-c-c
+void QRWidget::paintImage()
+{
+    QPainter painter(image);
+    //NOTE: I have hardcoded some parameters here that would make more sense as variables.
+    QRcode *qr = QRcode_encodeString(data.toStdString().c_str(), 1, QR_ECLEVEL_L, QR_MODE_8, 0);
+    
+    if(0 != qr)
+    {
+        QColor fg("black");
+        QColor bg("white");
+        painter.setBrush(bg);
+        painter.setPen(Qt::NoPen);
+        painter.drawRect(0, 0, size.width(), size.height());
+        painter.setBrush(fg);
+        const int s = qr->width>0 ? qr->width : 1;
+        const double w = width();
+        const double h = height();
+        const double aspect = w / h;
+        const double scale = ((aspect > 1.0) ? h : w) / s;
+        
+        for(int y = 0; y < s; y++)
+        {
+            const int yy = y * s;
+            for(int x = 0; x < s; x++)
+            {
+                const int xx = yy + x;
+                const unsigned char b = qr->data[xx];
+                if(b & 0x01)
+                {
+                    const double rx1 = x * scale,
+                                 ry1 = y * scale;
+                    QRectF r(rx1, ry1, scale, scale);
+                    painter.drawRects(&r, 1);
+                }
+            }
+        }
+        QRcode_free(qr);
+        painter.save();
+    }
+    else
+    {
+        QColor error("red");
+        painter.setBrush(error);
+        painter.drawRect(0, 0, width(), height());
+        qDebug() << "QR FAIL: " << strerror(errno);
+    }
+    
+    qr = 0;
+}

src/misc/qrwidget.h

@@ -0,0 +1,24 @@
+#ifndef QRWIDGET_H
+#define QRWIDGET_H
+
+// https://stackoverflow.com/questions/21400254/how-to-draw-a-qr-code-with-qt-in-native-c-c
+
+#include <QWidget>
+
+class QRWidget : public QWidget
+{
+    Q_OBJECT
+    
+public:
+    explicit QRWidget(QWidget *parent = 0);
+    void setQRData(QString data);
+    QString getImageAsText();
+  
+private:
+    QString data;
+    void paintImage();
+    QImage *image;
+    QSize size;
+};
+
+#endif // QRWIDGET_H

src/widget/form/settings/identityform.cpp

@@ -30,6 +30,8 @@
 #include <QClipboard>
 #include <QInputDialog>
 #include <QFileDialog>
+#include "src/misc/qrwidget.h"
+#include "qrencode.h"
 
 IdentityForm::IdentityForm() :
     GenericForm(tr("Identity"), QPixmap(":/img/settings/identity.png"))
@@ -126,6 +128,11 @@ void IdentityForm::setToxId(const QString& id)
 {
     toxId->setText(id);
     toxId->setCursorPosition(0);
+    
+    QRWidget *qrcode = new QRWidget();
+    qrcode->setQRData(id);
+    
+    toxId->setToolTip(qrcode->getImageAsText());
 }
 
 void IdentityForm::onLoadClicked()