feat (wip): implementing camera zooming and panning functionality

vtk/src/layers/BackgroundImage.cpp

@@ -3,6 +3,7 @@
 #include <vtkImageActor.h>
 #include <vtkImageData.h>
 #include <vtkImageReader2.h>
+#include <vtkTransformFilter.h>
 
 using std::string;
 
@@ -24,6 +25,13 @@ void BackgroundImage::updateImage() {
   imageReader->Update();
   imageData = imageReader->GetOutput();
 
+  // TODO: transform the iamge to the range [-1,1] and center it on (0,0)/
+  // This will allow the backgorundImage to share a camera with our other layers.
+  // Facilitating the cameraMovement callback.
+  
+  // vtkSmartPointer<vtkTransformFilter> transformFilter = createCartographicTransformFilter();
+  // transformFilter->SetInputData(imageData);
+
   vtkNew<vtkImageActor> imageActor;
   imageActor->SetInputData(imageData);
 
@@ -60,3 +68,8 @@ void BackgroundImage::setImagePath(string imagePath) {
   this->imagePath = imagePath;
   updateImage();
 }
+
+
+void BackgroundImage::setCamera(vtkCamera *cam) {
+  // TODO: fix the camera for this layer so this intentionally empty override can be removed.
+}

vtk/src/layers/BackgroundImage.h

@@ -32,6 +32,9 @@ public:
     * @param imagePath : String to the path of the new image to use.
     */
   void setImagePath(std::string imagePath);
+
+
+  void setCamera(vtkCamera *cam) override;
 };
 
 #endif

vtk/src/layers/EGlyphLayer.cpp

@@ -65,13 +65,13 @@ void EGlyphLayer::readCoordinates() {
   this->direction->SetNumberOfTuples(numLats*numLons); 
   points->Allocate(numLats*numLons);
 
-  auto camera = createNormalisedCamera();
-  ren->SetActiveCamera(camera);
+  // auto camera = createNormalisedCamera();
+  // ren->SetActiveCamera(camera);
 
   int i = 0;
   for (double lat : lats) {
     for (double lon : lons) {
-        cout << "lon: " << lon << " lat: " << lat << endl;
+        // cout << "lon: " << lon << " lat: " << lat << endl;
       direction->SetTuple3(i, 0.45, 0.90, 0); //FIXME: read this info from file
       points->InsertPoint(i++, lon, lat, 0);
       // see also https://vtk.org/doc/nightly/html/classvtkPolyDataMapper2D.html

vtk/src/layers/LGlyphLayer.cpp

@@ -42,7 +42,8 @@ LGlyphLayer::LGlyphLayer() {
     auto camera = createNormalisedCamera();
     ren->SetActiveCamera(camera);
 
-    auto transform = createCartographicTransformFilter();
+    // TODO: this line seemed to do nothing?
+    // auto transform = createCartographicTransformFilter();
 
     vtkSmartPointer<vtkTransformFilter> transformFilter = createCartographicTransformFilter();
     transformFilter->SetInputData(data);

vtk/src/layers/Layer.cpp

@@ -15,3 +15,8 @@ void Layer::updateData(int t) {
 void Layer::addObservers(vtkSmartPointer<vtkRenderWindowInteractor> interactor) {
     // By default, do nothing
 }
+
+
+void Layer::setCamera(vtkCamera *camera) {
+  this->getLayer()->SetActiveCamera(camera);
+}

vtk/src/layers/Layer.h

@@ -27,6 +27,11 @@ public:
     * @param interactor : pointer to the interactor that observers can be added to.
     */
   virtual void addObservers(vtkSmartPointer<vtkRenderWindowInteractor> interactor);
+
+  /** Sets the active camera for the vtkRenderer associated with this layer.
+    * Used to share one camera between multiple layers.
+    */ 
+  virtual void setCamera(vtkCamera *camera);
 };
 
 #endif