Limit outbound avatar size to 64kB

src/widget/form/profileform.cpp

@@ -192,6 +192,16 @@ void ProfileForm::setToxId(const QString& id)
 
 void ProfileForm::onAvatarClicked()
 {
+    auto picToPng = [](QPixmap pic)
+    {
+        QByteArray bytes;
+        QBuffer buffer(&bytes);
+        buffer.open(QIODevice::WriteOnly);
+        pic.save(&buffer, "PNG");
+        buffer.close();
+        return bytes;
+    };
+
     QString filename = QFileDialog::getOpenFileName(0,
         tr("Choose a profile picture"),
         QDir::homePath(),
@@ -214,11 +224,27 @@ void ProfileForm::onAvatarClicked()
         return;
     }
 
-    QByteArray bytes;
-    QBuffer buffer(&bytes);
-    buffer.open(QIODevice::WriteOnly);
-    pic.save(&buffer, "PNG");
-    buffer.close();
+    // Limit the avatar size to 64kB
+    // We do a first rescale to 256x256 in case the image was huge, then keep tryng from here
+    QByteArray bytes{picToPng(pic)};
+    if (bytes.size() > 65535)
+    {
+        pic = pic.scaled(256,256, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+        bytes = picToPng(pic);
+    }
+    if (bytes.size() > 65535)
+        bytes = picToPng(pic.scaled(128,128, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+    if (bytes.size() > 65535)
+        bytes = picToPng(pic.scaled(64,64, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+    if (bytes.size() > 65535)
+        bytes = picToPng(pic.scaled(32,32, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+
+    // If this happens, you're really doing it on purpose.
+    if (bytes.size() > 65535)
+    {
+        QMessageBox::critical(this, tr("Error"), tr("This image is too big"));
+        return;
+    }
 
     Nexus::getCore()->setAvatar(bytes);
 }