ENH: (Visu Refactoring) Implemented the ReadBuffer() method

Code/VisuRefac/otbImageWidget.h

@@ -57,8 +57,9 @@ public:
   typedef TInputImage                         InputImageType;
   /** Image region typedef */
   typedef typename InputImageType::RegionType RegionType;
-  /** Region size typedef */
+  /** Region size & index typedef */
   typedef typename RegionType::SizeType       SizeType;
+  typedef typename RegionType::IndexType      IndexType;
   /** Controller typedef */
   //typedef otb::ImageViewerController        ControllerType;
 
@@ -75,6 +76,11 @@ public:
   /** Set/Get the Controller */
   //itkSetObjectMacro(Controller,ControllerType);
   //itkGetObjectMacro(Controller,ControllerType);
+
+ /** Handle resizing event. This method is used by FLTK routines and
+    * should not be called on its own.
+    */
+  virtual void resize(int x, int y, int w, int h);
  
 protected:
   /** Constructor */
@@ -87,15 +93,33 @@ protected:
     * used by FLTK routines and should not be called on its own.
     */
   virtual void draw(void);
-  /** Handle resizing event. This method is used by FLTK routines and
-    * should not be called on its own.
-    */
-  virtual void resize(int x, int y, int w, int h);
   /** Handle the event from the users.  This method is used by FLTK 
     * routines and should not be called on its own.
     */
   virtual int  handle(int event);
 
+  /** Compute the linear buffer index according to the 2D region and
+   * its 2D index.This method is used when OTB_GL_USE_ACCEL is ON.
+   * \param index 2D index
+   * \param region 2D region
+   */
+  static inline unsigned int ComputeBufferIndex(const IndexType& index, const RegionType & region)
+  {
+    return (index[1]-region.GetIndex()[1])*3*region.GetSize()[0]+3*(index[0]-region.GetIndex()[0]);
+  }
+
+  /** Compute the linear buffer index according to the 2D region and
+   * its 2D index.This method is used when OTB_GL_USE_ACCEL is OFF. 
+   * The resulting buffer will be flipped over the X axis.
+   * \param index 2D index
+   * \param region 2D region
+   */
+  static inline unsigned int ComputeXAxisFlippedBufferIndex(const IndexType& iteratorIndex,const RegionType & region)
+  {
+    return  (region.GetSize()[1]-1+region.GetIndex()[1]-index[1])*3*region.GetSize()[0]+3*(index[0]-region.GetIndex()[0]);
+  }
+
+
 private:
   ImageWidget(const Self&);    // purposely not implemented
   void operator=(const Self&); // purposely not implemented

Code/VisuRefac/otbImageWidget.txx

@@ -19,6 +19,7 @@ PURPOSE.  See the above copyright notices for more information.
 #define __otbImageWidget_txx
 
 #include "otbImageWidget.h"
+#include "itkImageRegionConstIteratorWithIndex.h"
 
 namespace otb
 {
@@ -37,9 +38,11 @@ template <class TInputImage>
 ImageWidget<TInputImage>
 ::~ImageWidget()
 {
+  // Delete OpenGl buffer if needed
   if(m_OpenGlBuffer!=NULL)
     {
     delete [] m_OpenGlBuffer;
+    m_OpenGlBuffer = NULL;
     }
 }
 
@@ -75,7 +78,43 @@ void
 ImageWidget<TInputImage>
 ::ReadBuffer(InputImageType * image, RegionType & region)
 {
+  // Before doing anything, check if region is inside the buffered
+  // region of image
+  if(!image->GetBufferedRegion().IsInside(region))
+    {
+    itkExceptionMacro(<<"Region to read is oustside of the buffered region.");
+    }
+  // Delete previous buffer if needed
+  if(m_OpenGlBuffer != NULL)
+    {
+    delete [] m_OpenGlBuffer;
+    m_OpenGlBuffer = NULL;
+    }
+  // Allocate new memory
+  m_OpenGlBuffer = new unsigned char[3*region.GetNumberOfPixels()];
 
+  // Declare the iterator
+  itk::ImageRegionConstIteratorWithIndex<InputImageType> it(image,region);
+
+  // Go to begin
+  it.GoToBegin();
+
+  while(!it.IsAtEnd())
+    {
+    // Fill compute the linear index
+    #ifdef OTB_GL_USE_ACCEL
+    unsigned int index = ComputeBufferIndex(it.GetIndex(),region);
+    #else
+    unsigned int index = ComputeXAxisFlippedBufferIndex(it.GetIndex(),region);
+    #endif
+    // Fill the buffer
+    m_OpenGlBuffer[index]  =it.Get()[0];
+    m_OpenGlBuffer[index+1]=it.Get()[1];
+    m_OpenGlBuffer[index+2]=it.Get()[2];
+    ++it;
+    }
+  // Last, updating buffer size
+  m_OpenGlBufferSize = region.GetSize();
 }
 
 template <class TInputImage>