Pencil

The Pencil Project`s unique mission is to build a free and opensource tool for making Diagrams and GUI prototyping that everyone can use. Top features: Built-in stencils for diagraming and prototyping Multi-PaGE document with background page On-screen text editing with rich-text supports PNG rasterizing Undo/redo supports Installing user-defined stencils Standard drawing operations: aligning, z-ordering, scaling, rotating... Cross-platforms Adding external objects And much more...