Fix QPixmap::scaled: Pixmap is a null pixmap error

imagescrollarea.cpp

@@ -32,7 +32,7 @@ void ImageScrollArea::setImage(const QPixmap &img)
 
 void ImageScrollArea::setScale(float scale)
 {
-    if(scale > 4 || (scale < 0.2 && scale > 0))
+    if(scale > 4 || (scale < 0.2 && scale > 0) || m_pixmap.isNull())
         return;
 
     m_scale = scale;
@@ -92,7 +92,7 @@ void ImageScrollArea::mousePressEvent(QMouseEvent *event)
 
 void ImageScrollArea::resizeEvent(QResizeEvent *event)
 {
-    if(m_scale < 0)
+    if(m_scale < 0 && !m_pixmap.isNull())
     {
         m_label->setPixmap(m_pixmap.scaled(event->size(), Qt::KeepAspectRatio, Qt::SmoothTransformation));
         m_label->resize(event->size());