title: search for shapes in BMP image file
body: <p>I have an image processing question, using C#.</p>
  
  <p>Say I have some schematic diagrams in BMP format, the diagram contains component shapes which are connected to each other.</p>
  
  <p>I wrote a simple program to detect square shapes in the diagram as one component, and record the location of it. However, the next level is to detect more complicated shapes like a few arcs joined together. Note that these shapes can be different sizes in the image. Does anyone know any good method of doing it? without downloading any library (this is my limitation now).</p>
  
  <p>After detecting the shapes, I also need to record which shape is connected to which, so later on, I can redraw them. I have one week to do this, so thanks a lot for any help!!</p>
  
  <p>I'm using C#.</p>