为提高图形轮廓信息获取效率和克服现有方法需角度判别、计算量大等问题，提出了一种基于中点判别法的视图轮廓信息获取方法。该方法首先将各候选路径按照象限进行分区，并通过直接比较坐标值来快速排除一部分候选路径；然后将难以判别的候选路径，通过中点判别法来确定候选路径走向。由于中点判别法只需进行移位和加减运算，并避免了复杂的角度计算和求交运算，因而计算效率高。该方法特别适用于复杂工程图轮廓信息的自组织。试验结果表明，该算法不仅速度快，且稳定可靠。

The information of view outline is one of the important issues in computer Graphics.It plays an important role in automatic partitioning of engineering drawings, assembly diagram processing and dimension arrangement. Lots of experts have proposed many methods to these issues. To improve the efficiency of acquisition of view outline information and solve the problem of existing methods which require angle discriminance and much calculation , this paper puts forward automatically acquires the information of view outline based on midpoint method. At first, this method sorts the candidate path according to the quadrant of coordinate system, and then fleetly eliminates some candidate path by directly comparing their coordinate values. Thirdly, according to the midpoint method, the candidate path which was distinguished arduously can be determined finally. 〖JP2〗The midpoint method only includes shift and subtraction calculation, avoids complex angle calculation and nodical acquisition calculation, so the efficiency of this method can be improved. This method is applicable in automatic organization of complex view outline information. The result of test indicates that this method is a simple, highly efficient and reliable algorithm.