From e354df7172efbe25e94f1c6ae5516912dad1d114 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Fri, 20 Jul 2018 15:41:45 +0200
Subject: [server] Resize thumbs server side on mismatch

The server requests the appropriate size thumbnail from the client so no
bandwidth will be wasted. However, due to privacy concerns, the client
might actually send a thumb that's smaller than requested, resulting in
a tiny thumbnail on the server with huge gray borders. The server will
now scale up the image in those cases.
We'd actually also scale the image down now if it were too large, but
this doesn't happen under normal circumstances.
---
 src/server/connectionframe/connectionframe.cpp | 41 ++++++++++++++++----------
 1 file changed, 25 insertions(+), 16 deletions(-)

(limited to 'src/server/connectionframe/connectionframe.cpp')

diff --git a/src/server/connectionframe/connectionframe.cpp b/src/server/connectionframe/connectionframe.cpp
index fb2c96a..875e031 100644
--- a/src/server/connectionframe/connectionframe.cpp
+++ b/src/server/connectionframe/connectionframe.cpp
@@ -17,9 +17,9 @@
 #include "connectionframe.h"
 #include "../mainwindow/mainwindow.h"
 #include "../net/client.h"
-#include <QPixmap>
 #include <QImage>
 #include <cassert>
+#include <cmath>
 
 static QString style_student(
     "QLabel{ background-color: #FFF; border-radius: 2px; color: black;} \
@@ -173,7 +173,7 @@ void ConnectionFrame::assignClient(Client* client)
 {
 	assert(_client == NULL);
 	connect( client, SIGNAL(disconnected()), this, SLOT(onClientDisconnected()) );
-	connect( client, SIGNAL(thumbUpdated(Client*, const QPixmap&, const QByteArray&)), this, SLOT(onThumbUpdated(Client*, const QPixmap&, const QByteArray&)) );
+	connect( client, SIGNAL(thumbUpdated(Client*, const QImage&)), this, SLOT(onThumbUpdated(Client*, const QImage&)) );
 	connect( client, SIGNAL(vncServerStateChange(Client*)), this, SLOT(updateAppearance()));
 	connect( client, SIGNAL(vncClientStateChange(Client*)), this, SLOT(updateAppearance()));
 	connect( client, SIGNAL(stateChanged()), this, SLOT(updateAppearance()));
@@ -192,11 +192,15 @@ void ConnectionFrame::assignClient(Client* client)
  */
 void ConnectionFrame::showDefaultThumb()
 {
-	const int width = this->width() - 6;
-	const int height = this->height() - 8 - _lblHostName->height() - _lblUserName->height();
-	_remoteScreen = term->pixmap(width, height, QIcon::Normal, QIcon::On);
-	this->repaint();
-	//_imgScreen->setPixmap(_remoteScreen);
+	_remoteScreen = term->pixmap(_desiredThumbSize, QIcon::Normal, QIcon::On).toImage();
+	this->update();
+}
+
+void ConnectionFrame::calcDesiredThumbSize(const QSize &frameSize)
+{
+	const int width = frameSize.width() - 10;
+	const int height = frameSize.height() - 12 - _lblHostName->height() - (_lblUserName->isHidden() ? 0 : _lblUserName->height());
+	_desiredThumbSize = QSize(width, height);
 }
 
 void ConnectionFrame::updateLabels()
@@ -210,6 +214,7 @@ void ConnectionFrame::updateLabels()
 		_lblUserName->setText(_client->name());
 		_lblUserName->show();
 	}
+	calcDesiredThumbSize(this->size());
 }
 
 /**
@@ -226,7 +231,6 @@ void ConnectionFrame::mouseReleaseEvent(QMouseEvent* event)
 		if ((this->pos() - _previousPosition).manhattanLength() > _startDragDistance ) {
 			emit frameMoved(this);
 		} else {
-			qDebug("Clicked");
 			move(_previousPosition);
 			emit clicked(this);
 		}
@@ -308,8 +312,16 @@ void ConnectionFrame::paintEvent(QPaintEvent *event)
 		return;
 	}
 
+	if (!_desiredThumbSize.isEmpty()) {
+		if (abs(100 - ((_remoteScreen.width() * 100) / _desiredThumbSize.width())) > 5
+				&& abs(100 - ((_remoteScreen.height() * 100) / _desiredThumbSize.height())) > 5) {
+			qDebug() << "Rescale thumb" << _remoteScreen.size() << "to" << _desiredThumbSize;
+			_remoteScreen = _remoteScreen.scaled(_desiredThumbSize, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+		}
+	}
+
 	QPainter painter(this);
-	painter.drawPixmap((this->width() - _remoteScreen.width()) / 2, 4, _remoteScreen);
+	painter.drawImage((this->width() - _remoteScreen.width()) / 2, 4, _remoteScreen);
 	event->accept();
 }
 
@@ -324,9 +336,7 @@ void ConnectionFrame::timerEvent(QTimerEvent* /* event */ )
 	++_timerCounter;
 	if (_client->isActiveVncServer() && _timerCounter % 5 != 0)
 		return;
-	const int width = this->width() - 8;
-	const int height = this->height() - 9 - _lblHostName->height() - _lblUserName->height();
-	_client->requestThumb(width, height);
+	_client->requestThumb(_desiredThumbSize);
 }
 
 /**
@@ -417,9 +427,9 @@ void ConnectionFrame::onClientDisconnected()
 		_timerId = 0;
 	}
 	_client = NULL;
-	showDefaultThumb();
 	updateLabels();
 	updateAppearance();
+	showDefaultThumb();
 }
 
 /**
@@ -427,11 +437,10 @@ void ConnectionFrame::onClientDisconnected()
  * @param client
  * @param thumb
  */
-void ConnectionFrame::onThumbUpdated(Client* client, const QPixmap& thumb, const QByteArray&)
+void ConnectionFrame::onThumbUpdated(Client* client, const QImage& thumb)
 {
 	assert(client == _client);
 	_remoteScreen = thumb;
-	//_imgScreen->setPixmap(_remoteScreen);
-	this->repaint();
+	this->update();
 }
 
-- 
cgit v1.2.3-55-g7522