created viewer sizer objects

app/widget/viewer/CMakeLists.txt

@@ -20,5 +20,7 @@ set(OLIVE_SOURCES
   widget/viewer/viewer.cpp
   widget/viewer/viewerglwidget.h
   widget/viewer/viewerglwidget.cpp
+  widget/viewer/viewersizer.h
+  widget/viewer/viewersizer.cpp
   PARENT_SCOPE
 )

app/widget/viewer/viewersizer.cpp

@@ -0,0 +1,69 @@
+#include "viewersizer.h"
+
+ViewerSizer::ViewerSizer(QWidget *parent) :
+  QWidget(parent),
+  widget_(nullptr),
+  aspect_ratio_(0)
+{
+}
+
+void ViewerSizer::SetWidget(QWidget *widget)
+{
+  if (widget_ != nullptr) {
+    widget_->setParent(nullptr);
+
+    disconnect(widget_, SIGNAL(SizeChanged(int, int)), this, SLOT(SizeChangedSlot(int, int)));
+  }
+
+  widget_ = widget;
+
+  if (widget_ != nullptr) {
+    widget_->setParent(this);
+
+    connect(widget_, SIGNAL(SizeChanged(int, int)), this, SLOT(SizeChangedSlot(int, int)));
+
+    UpdateSize();
+  }
+}
+
+void ViewerSizer::resizeEvent(QResizeEvent *event)
+{
+  QWidget::resizeEvent(event);
+
+  UpdateSize();
+}
+
+void ViewerSizer::UpdateSize()
+{
+  if (widget_ == nullptr) {
+    return;
+  }
+
+  if (qIsNull(aspect_ratio_)) {
+    widget_->setVisible(false);
+    return;
+  }
+
+  widget_->setVisible(true);
+
+  double our_aspect_ratio = static_cast<double>(width()) / static_cast<double>(height());
+
+  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_));
+  } else {
+    // This container is taller than the image, scale by width
+    child_size.setHeight(qRound(child_size.width() / aspect_ratio_));
+  }
+
+  widget_->resize(child_size);
+}
+
+void ViewerSizer::SizeChangedSlot(int width, int height)
+{
+  aspect_ratio_ = static_cast<double>(width) / static_cast<double>(height);
+
+  UpdateSize();
+}

app/widget/viewer/viewersizer.h

@@ -0,0 +1,54 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2019 Olive Team
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+***/
+
+#ifndef VIEWERSIZER_H
+#define VIEWERSIZER_H
+
+#include <QWidget>
+
+class ViewerSizer : public QWidget
+{
+  Q_OBJECT
+public:
+  ViewerSizer(QWidget* parent = nullptr);
+
+  /**
+   * @brief Set the widget to be adjusted by this widget
+   *
+   * ViewerSizer takes ownership of this widget
+   */
+  void SetWidget(QWidget* widget);
+
+protected:
+  virtual void resizeEvent(QResizeEvent *event) override;
+
+private:
+  void UpdateSize();
+
+  QWidget* widget_;
+
+  double aspect_ratio_;
+
+private slots:
+  void SizeChangedSlot(int width, int height);
+
+};
+
+#endif // VIEWERSIZER_H