This paper presents a GPU-based real-time line-drawing algorithm. By approximating the differential properties of the 3D mesh, the algorithm combines a view dependent and a view independent line-drawing approach to render the feature lines in real time. It firstly extracts view-dependent feature lines in the image space according to view curvatures, and renders view-independent feature lines as supplement by picking in style-texture according to the standardized principle curvatures. The algorithm works totally in pixel shader where two cues (view-dependent and view-independent cues) are processed, and produces pleasant results. As the experimental results showed, since all computation takes place in the image space with GPU, the performance is great. Moreover, by using the style-texture, the algorithm has a good control on styling which covers the shortages of the image-based line-drawing algorithms. The algorithm is not only a real-time line-drawing method but also a first step to the further application of artistic simulations, such as Chinese ink painting.