GDI/GDI+绘图函数缺陷与避免方法研究

Study on defects in GDI/GDI+ rendering functions and solutions

首次报告了Windows的GDI/GDI+绘图函数存在的几类缺陷,一类缺陷是GDI绘线函数在最后一点少绘一个像素;另一类缺陷是GDI的绘制或填充矩形或椭圆的函数以及填充多边形函数,它们都在右边界和下边界少绘一列/排像素。在GDI+中,绘线的缺陷已经改正,但矩形与椭圆的绘制与充填函数以及多边形填充函数的缺陷有的依然存在,且缺陷方式与GDI不同。GDI+有缺省与精细两种模式,这两种模式下的缺陷表现方式也不一样。虽然这些缺陷对于一般的可视化应用程序没有什么影响,但对于一些特殊的应用则会导致不精确的结果。给出了测试数据以及在应用程序中避免这些缺陷的方法。

Some defects in GDI/GDI＋ rendering functions in Windows are reported firstly.One sort of defect is GDI＇s drawing line functions which are always absent a pixel in the end point.Another sort of defect is GDI＇s drawing/filling rectangle/ellipse functions and filling polygon function which are always absent a row pixels in lower edge and right edge.In GDI＋,the defect in drawing line is removed,but some bugs in drawing/filling rectangle/polygon are existed still,only in different forms.GDI＋has different smoothing modes,they also have different absents in different mode.All these bugs have no effective for general visualization applications.But for some especial application,it may make result imprecise.The test data and some methods are provided to avoid these bugs in application program.