fix zoom detection issue in old OSX versions

src/node_canvas.cpp

@@ -621,6 +621,7 @@ void NodeCanvas::reset_camera()
 void NodeCanvas::create_buffers()
 {
     auto new_size = GetSize() * m_density;
+    LOG("NodeCanvas::create_buffers size: %d x %d density %f", (int)new_size.x, (int)new_size.y, m_density);
     m_canvas->m_mixer.create((int)new_size.x * m_canvas->m_mixer_scale,
         (int)new_size.y * m_canvas->m_mixer_scale, -1, GL_RGBA8);
     m_blender_rtt.create((int)new_size.x, (int)new_size.y, -1, GL_RGBA8);