Remove contents margins from sizehint when preserving aspect ratio

* This prevents a feedback loop where the label resizes wider to make
  room for the margins, then the margins get bigger to keep the image
  centred/scaled properly, etc.

qrenderdoc/Widgets/Extended/RDLabel.cpp

@@ -33,6 +33,26 @@ RDLabel::~RDLabel()
 {
 }
 
+QSize RDLabel::sizeHint() const
+{
+  QSize sz = QLabel::sizeHint();
+
+  if(m_preserveRatio)
+    sz.setWidth(sz.width() - contentsMargins().left() - contentsMargins().right());
+
+  return sz;
+}
+
+QSize RDLabel::minimumSizeHint() const
+{
+  QSize sz = QLabel::minimumSizeHint();
+
+  if(m_preserveRatio)
+    sz.setWidth(sz.width() - contentsMargins().left() - contentsMargins().right());
+
+  return sz;
+}
+
 void RDLabel::mousePressEvent(QMouseEvent *event)
 {
   emit(clicked(event));

qrenderdoc/Widgets/Extended/RDLabel.h

@@ -33,6 +33,9 @@ public:
   explicit RDLabel(QWidget *parent = 0);
   ~RDLabel();
 
+  QSize sizeHint() const override;
+  QSize minimumSizeHint() const override;
+
   void setPreserveAspectRatio(bool preserve) { m_preserveRatio = preserve; }
   bool preserveAspectRatio() { return m_preserveRatio; }
 signals: