/*!

  \defgroup jkqtmathtext_renderingmodel JKQTMathText Rendering Model
  \ingroup jkqtmathtext_general

  JKQTMathText parses an (LaTeX) input string of mathematicalkmarkup and in a first step generates a memory representation of the it (cf. \ref jkqtmathtext_items ).
  Then this memory representation is used to draw the represented math using the renndering API of <a href="https://doc.qt.io/qt-6/qpainter.html">QPainter</a>.
  
  As an example, we look at the following LaTeX markup, representing the solution to a quadratic equation:
  
  \code{.tex}
    $x_{1/2} = \frac{-b\pm\sqrt{b^2-4ac}}{2a}$
  \endcode
  
  LaTeX itself would render this as follows:
  
  \image html jkqtmathtext/jkqtmathtext_doc_quadraticeq_latex.png
  
  JKQTMathText produces this output:

  \image html jkqtmathtext/jkqtmathtext_doc_quadraticeq.png

  The memory representation of the expression above looks like this:
  
  \image html jkqtmathtext/jkqtmathtext_doc_quadraticeq_tree.png

  \note  The memory representation is independent of the actual math markup language (e.g. LaTeX) which was initially parsed. 
  But of course it is modelled, so the features of the supported markup languages are supported by the memory model.


  You can see that each node corresponds to a box, if these are overlayed over the rendering:
  
  \image html jkqtmathtext/jkqtmathtext_doc_quadraticeq_boxes.png
  
  
  The box, representing each node, is characterized by its width and height, as well as the ascent (or "baseline-height"):
  
  \image html jkqtmathtext_node_geo.png
  
   

*/