created viewer sizer objects

2019-08-30 00:43:24 +10:00
parent a0484bf43e
commit 033287e810
3 changed files with 125 additions and 0 deletions
@@ -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();
+}