Abstract: 2.5D graphics is one of the key technologies for creating computer cartoon animation. This paper proposes a novel method, colored double-sided 2.5D graphics, to generate 2.5D graphics with color transition based on a set of vector-
graphics-primitives defined by users. The basic idea behind this method is the diffusion curves technique for the double-sided 2.5D graphics. The method first takes a group of curves with pre-defined colors as its source data, and then performs a classic 2.5D folding operator on the source curves with several user-specified parameters. A color diffusing process is employed in each local area limited by curves on front and back 2.5D local layers respectively. Once the diffusing processes are finished, a 2.5D image with elegant color transition can finally be obtained. The results show that the colored double-
sided 2.5D graphics method can work well with various source data and can generates both static 2.5D images and 2.5D cartoon animations.

Key words: cartoon animation, 2.5D graphics, diffusion curves, coloring method

摘要： 2.5D图形算法是计算机卡通动画生成的关键技术。通过将扩散曲线方法引入双面2.5D图形，提出着色双面2.5D图形技术。该技术首先读入矢量表示的图形色源曲线，再根据用户指定的操作对色源曲线进行折叠处理，由矢量曲线所对应的色源颜色对2.5D图形的正反面局部层区域进行扩散着色，最终生成具有渐变着色效果的2.5D图形。实验表明，该方法绘制出的2.5D图形颜色过渡自然，视觉效果好，克服了传统2.5D矢量图形绘制效果颜色单一、颜色过渡生硬等问题。该方法可用于生成静态2.5D图像或动态2.5D动画。

关键词: 卡通动画, 2.5D图形, 扩散曲线, 着色技术