Aliasing is a long-standing problem in computer graphics. Many techniques have been developed to anti-alias fast and efficiently. Based on the most advanced antialiasing algorithm, this article presents a new approach to deal with the drawback in edge detection and reconstructs the original morphological antialiasing technique. The new approach uses local edge information to calculate the range of the line slope, and then predicts more probable end-points for straight lines. While the reconstructing of straight lines is much better, this technique use minor additive cost. Compared with previous morphological antialiasing techniques, this work not only reconstructs the local edge shapes, but also captures the global edge shapes, which in return helps enormously in antialiasing lines. The use of such global slope-based shape information improves the gradients of straight lines, makes inclined lines more continuous, and therefore, obtains better rendering result.