PowerPlot是一个iOS可视化类库，可以用于科学和商业领域的可视化图表绘制。可以绘制柱状图、折线图等等，是一个可以高度定制化的类库，满足开发者大部分可视化绘制需求-PowerPlot is a to iOS visualization class library can be used for the visualization of scientific and commercial fields diagramming. Can draw a bar chart, line chart

cocoa类继承图，介绍了cocoa库里的类继承关系。-classes in cocoa. shows the classes and their relationship in cocoa.