Improve appearance for non-integer scale factors.

src/GUI/AudioPreviewer.cpp

@@ -152,9 +152,10 @@ void AudioPreviewer::paintEvent(QPaintEvent* event) {
 
 	painter.setPen(QColor(0, 0, 0));
 	painter.setBrush(Qt::NoBrush);
+	painter.setRenderHint(QPainter::Antialiasing);
 	for(unsigned int c = 0; c < n; ++c) {
 		int y1 = h * c / n, y2 = h * (c + 1) / n;
-		painter.drawRect(0, y1, w, y2 - y1);
+		painter.drawRect(QRectF(0.5, (qreal) y1 + 0.5, (qreal) w, (qreal) (y2 - y1)));
 	}
 
 }

src/GUI/PageWelcome.cpp

@@ -36,6 +36,7 @@ PageWelcome::PageWelcome(MainWindow* main_window)
 	{
 		QLabel *label_logo = new QLabel(scrollarea_contents);
 		label_logo->setPixmap(QPixmap(":/header.png"));
+		label_logo->setScaledContents(true);
 		QLabel *label_welcome = new QLabel(scrollarea_contents);
 		label_welcome->setText(tr("<p>Welcome to SimpleScreenRecorder!</p>\n\n"
 								  "<p>Despite the name, this program actually has a lot of options. Don't worry though, there are really just two things that you "

src/GUI/VideoPreviewer.cpp

@@ -206,6 +206,7 @@ void VideoPreviewer::paintEvent(QPaintEvent* event) {
 		// draw the border
 		painter.setPen(Qt::black);
 		painter.setBrush(Qt::NoBrush);
+		painter.setRenderHint(QPainter::Antialiasing);
 		painter.drawRect(QRectF(draw_rect).adjusted(-0.5, -0.5, 0.5, 0.5));
 
 	}