wrote viewer resizing container

app/widget/viewer/viewer.cpp

@@ -24,17 +24,24 @@
 #include <QResizeEvent>
 #include <QVBoxLayout>
 
+#include "viewersizer.h"
+
 ViewerWidget::ViewerWidget(QWidget *parent) :
   QWidget(parent)
 {
   // Set up main layout
   QVBoxLayout* layout = new QVBoxLayout(this);
-  layout->setSpacing(0);
   layout->setMargin(0);
 
   // Create main OpenGL-based view
+  ViewerSizer* sizer = new ViewerSizer(this);
+  layout->addWidget(sizer);
+
   gl_widget_ = new ViewerGLWidget(this);
-  layout->addWidget(gl_widget_);
+  sizer->SetWidget(gl_widget_);
+
+  // FIXME: Hardcoded values
+  sizer->SetSize(1920, 1080);
 
   // Create time ruler
   ruler_ = new TimeRuler(false, this);

app/widget/viewer/viewersizer.cpp

@@ -9,23 +9,29 @@ ViewerSizer::ViewerSizer(QWidget *parent) :
 
 void ViewerSizer::SetWidget(QWidget *widget)
 {
-  if (widget_ != nullptr) {
-    widget_->setParent(nullptr);
-
-    disconnect(widget_, SIGNAL(SizeChanged(int, int)), this, SLOT(SizeChangedSlot(int, int)));
-  }
+  // Delete any previous widgets occupying this space
+  delete widget_;
 
   widget_ = widget;
 
   if (widget_ != nullptr) {
     widget_->setParent(this);
 
-    connect(widget_, SIGNAL(SizeChanged(int, int)), this, SLOT(SizeChangedSlot(int, int)));
-
     UpdateSize();
   }
 }
 
+void ViewerSizer::SetChildSize(int width, int height)
+{
+  if (height == 0) {
+    aspect_ratio_ = 0;
+  } else {
+    aspect_ratio_ = static_cast<double>(width) / static_cast<double>(height);
+  }
+
+  UpdateSize();
+}
+
 void ViewerSizer::resizeEvent(QResizeEvent *event)
 {
   QWidget::resizeEvent(event);
@@ -39,6 +45,7 @@ void ViewerSizer::UpdateSize()
     return;
   }
 
+  // If the aspect ratio is 0, the widget is always hidden
   if (qIsNull(aspect_ratio_)) {
     widget_->setVisible(false);
     return;
@@ -48,22 +55,19 @@ void ViewerSizer::UpdateSize()
 
   double our_aspect_ratio = static_cast<double>(width()) / static_cast<double>(height());
 
+  QPoint child_pos;
   QSize child_size = size();
 
   if (our_aspect_ratio > aspect_ratio_) {
     // This container is wider than the image, scale by height
     child_size.setWidth(qRound(child_size.height() * aspect_ratio_));
+    child_pos.setX(width() / 2 - child_size.width() / 2);
   } else {
     // This container is taller than the image, scale by width
     child_size.setHeight(qRound(child_size.width() / aspect_ratio_));
+    child_pos.setY(height() / 2 - child_size.height() / 2);
   }
 
   widget_->resize(child_size);
-}
-
-void ViewerSizer::SizeChangedSlot(int width, int height)
-{
-  aspect_ratio_ = static_cast<double>(width) / static_cast<double>(height);
-
-  UpdateSize();
+  widget_->move(child_pos);
 }

app/widget/viewer/viewersizer.h

@@ -23,6 +23,15 @@
 
 #include <QWidget>
 
+/**
+ * @brief A container widget that enforces the aspect ratio of a child widget
+ *
+ * Using a provided width and height, this widget calculates the aspect ratio and forces the child widget to stay
+ * confined to that aspect ratio and centered within the widget.
+ *
+ * The aspect ratio is calculated width divided by height. If the aspect ratio is zero (either width or height == 0),
+ * the widget is hidden until a valid size is provided.
+ */
 class ViewerSizer : public QWidget
 {
   Q_OBJECT
@@ -32,23 +41,41 @@ public:
   /**
    * @brief Set the widget to be adjusted by this widget
    *
-   * ViewerSizer takes ownership of this widget
+   * ViewerSizer takes ownership of this widget. If a widget was previously set, it is destroyed.
    */
   void SetWidget(QWidget* widget);
 
+  /**
+   * @brief Set resolution to use
+   *
+   * This is not the actual resolution of the viewer, it's used to calculate the aspect ratio
+   */
+  void SetChildSize(int width, int height);
+
 protected:
+  /**
+   * @brief Listen for resize events to ensure the child widget remains correctly sized
+   */
   virtual void resizeEvent(QResizeEvent *event) override;
 
 private:
+  /**
+   * @brief Main sizing function, resizes widget_ to fit aspect_ratio_ (or hides if aspect ratio is 0)
+   */
   void UpdateSize();
 
+  /**
+   * @brief Reference to widget
+   *
+   * If this is nullptr, all sizing operations are no-ops
+   */
   QWidget* widget_;
 
+  /**
+   * @brief Aspect ratio calculated from the size provided by SetChildSize()
+   */
   double aspect_ratio_;
 
-private slots:
-  void SizeChangedSlot(int width, int height);
-
 };
 
 #endif // VIEWERSIZER_H