As a user types, characters are built into a composition string. The string is displayed in the default Composition window if the window that has the focus is IME-unaware. IME-aware windows display the composition string in their own window. The remainder of this section assumes that the string is displayed in the default Composition window. Depending on the conversion mode, the Composition window displays either converted or unconverted text.
An application can call the ImmGetCompositionWindow function to retrieve information about the Composition window contained in the COMPOSITIONFORM structure, or it can call the ImmGetCompositionFont function to get the logical font currently used to display characters in the Composition window.