摘要
鉴于制作手工剪纸动画背景效率低、耗资大的问题,本文提出了一个计算机生成剪纸风格动画背景的方法。首先对构成手工剪纸动画背景的剪纸图案进行分类,包括种类繁多的树、花、草、山石、建筑等。其中树的结构相对最为复杂,种类也最为繁多。典型的包括松树、竹子、棕榈树、柳树、椰子树等等。
其次用计算机方法生成这些剪纸图案模型。我们建立了一些剪纸图案库,用户创作时,可通过设定高度、宽度、倾角等参数来指定剪纸图案的各项属性,也可以从我们精心设计的剪纸图案库中直接读入设定好参数的相应剪纸图案。鉴于剪纸图案之间的相互覆盖会严重影响其美观,我们在系统中加入了相交判断系统来减少剪纸图案之间的相互覆盖问题。同时我们也加入了鼠标交互系统,一方面能让用户自己通过鼠标拖拽避免剪纸图案之间的相交,另一方面极大的方便了用户的创作,且加大了创作的灵活性。利用鼠标交互系统,用户可以轻松的按照意愿改变剪纸图案的形状、大小、坐标等属性。通过将各类剪纸图案放入不同的位置,便可组合出一幅幅完全不一样的剪纸动画背景图。用户利用此系统创作的作品,可以随时保存在用户作品库中,以便下次直接导入。
最后,我们加入了简单的动画,可使背景图中大部分剪纸图案随风摆动或者停止摆动。我们通过双缓冲技术解决了播放动画时的闪烁问题。
Making Chinese paper cut-out by hand is an expensive task. In this paper we propose a method for generating animation background with the style of paper-cuts by computer to emulate hand-made paper-cuts. First we classify the paper-cuts graphics of animation background with the style of paper-cuts, including a variety of trees, flowers, grasses, mountains, bridges, etc. The structure of the tree is relatively the most complicated and most diverse, typically including pine, bamboo, palm trees, willows, palm trees, etc.
Secondly, we use computer to generate the models of these paper-cut patterns. We have built a large paper-cut pattern library. Users can specify the various properties of paper-cutting patterns by setting height, width, inclination and other parameters, and can also import corresponding paper-cut patterns from the paper-cuts library directly. In order to avoid the overlap between different paper-cut objects, we check the object-intersection. We also provide an interactive tool that allows users to drag relevant paper-cut patterns on the scene. Furthermore, users can easily change the shape, size, coordinates and other attributes of paper-cut patterns by setting relevant parameters. By composing various types of paper-cut patterns into different positions, users can create a background scene for paper-cut animation. The scene can be saved for future use.
Finally, we add a simple animation to make the majority of paper-cutting patterns of the background image to swing like in the wind. We solve the flicker problem when playing animation by the double-buffer technique.
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