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+* Drawing
+
+	Mono provides two mechanism to draw.  The first exposes the
+	Microsoft System.Drawing API and the second exposes the <a
+	href="http://www.cairographics.org">Cairo</a> API.
+
+* System.Drawing
+
+	The System.Drawing implementation in Mono is designed to be
+	compatible with the Microsoft API.  The imaging model is very
+	similar to the PDF 1.4 composition-based imaging model.
+
+	Our implementation is a C# wrapper around the GDI+ C API (also
+	called the <a
+	href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdicpp/GDIPlus/GDIPlusReference.asp">"GDI+
+	Flat API"</a>).
+
+	This means that the C# code is the same for Windows and Unix
+	systems.  The following graph explains the situation:
+
+	<center>
+	<img src="images/system-drawing.png">
+	</center>
+
+	In Windows Mono uses the GDI+ library that is included with
+	the operating system (<tt>GDIPLUS.DLL</tt>, while in Unix we
+	provide an implementation of this API in the
+	<tt>libgdiplus.so</tt> shared library.  Our
+	<tt>libgdiplus.so</tt> has the same C Flat API as the
+	<tt>GDIPLUS.DLL</tt>.  Our implementation uses Cairo to do
+	the heavy lifting.
+
+	The implementation of GDI+ lives in the libgdiplus cvs module
+	and requires <a
+	href="http://www.cairographics.org">Cairo</a> to be installed
+	to get the package built.
+
+	The C# code that implement System.Drawing is the same for
+	Windows and Unix builds.
+
+	Since this is an implementation of an existing Microsoft API
+	no architectural changes go here.
+
+* Mono.Cairo
+
+	The Mono.Cairo.dll assembly exposes the Cairo API to managed
+	applications.  The mapping is a pretty straightforward one,
+	and the programming model is very close to the C API.
+
+	This API is still unstable due to the nature of the underlying
+	API being used and will be revisited as Cairo evolves.