简单的Delphi黑板及黑板擦程序，类似于画图程序，画笔画线条，橡皮擦清除画笔。源代码只包括了一个核心类模块，其它代码诸如窗体之类的要自己加了-Simple Delphi blackboard eraser program, similar to the Paint program, the painting strokes eraser to clear brush. The source code includes only a core class module, and other co