viewer: rewrote pixel sampling coordinate system

Fixes #1395

app/widget/manageddisplay/manageddisplay.cpp

@@ -55,6 +55,10 @@ ManagedDisplayWidget::ManagedDisplayWidget(QWidget *parent) :
             &ManagedDisplayWidgetOpenGL::frameSwapped,
             this, &ManagedDisplayWidget::frameSwapped, Qt::DirectConnection);
 
+    connect(static_cast<ManagedDisplayWidgetOpenGL*>(inner_widget_),
+            &ManagedDisplayWidgetOpenGL::OnMouseMove,
+            this, &ManagedDisplayWidget::InnerWidgetMouseMove);
+
     // Create OpenGL renderer
     attached_renderer_ = new OpenGLRenderer(this);
   } else {

app/widget/manageddisplay/manageddisplay.h

@@ -21,6 +21,7 @@
 #ifndef MANAGEDDISPLAYOBJECT_H
 #define MANAGEDDISPLAYOBJECT_H
 
+#include <QMouseEvent>
 #include <QOpenGLContext>
 #include <QOpenGLWidget>
 
@@ -46,6 +47,8 @@ signals:
 
   void OnDestroy();
 
+  void OnMouseMove(QMouseEvent* e);
+
 protected:
   virtual void initializeGL() override
   {
@@ -60,6 +63,13 @@ protected:
     emit OnPaint();
   }
 
+  virtual void mouseMoveEvent(QMouseEvent* e) override
+  {
+    emit OnMouseMove(e);
+
+    QOpenGLWidget::mouseMoveEvent(e);
+  }
+
 private slots:
   void DestroyListener()
   {
@@ -144,6 +154,8 @@ signals:
 
   void frameSwapped();
 
+  void InnerWidgetMouseMove(QMouseEvent* event);
+
 protected:
   /**
    * @brief Provides access to the color processor (nullptr if none is set)