HanziCraft

Decomposition Levels:
Level 1: Only divided once. So only two components.
Level 2: Radical Decomposition. The character gets decomposed into its lowest radical components. For the complete list visit the Radical wikipedia page.
Level 3: Graphical Decomposition. Shows all the strokes & lowest level of components that make up the character.
If you see questions marks or too many "block" characters, especially when it comes to level 3 decomposition you might need the correct font.