Computer Assisted Generation Of Paper Cut-out Images

In the recent 10 years, Non-Photorealistic Rendering (NPR), a new realm of computer graphics, is rapidly growing. The emergence of NPR makes the rendering become more selectable, more individually and more artistically, it provides more targets and more chooses than before. Recently, Non-Photorealistic Rendering develops rapidly. Paper cut-out is one of the traditional folk arts in China. Just because the tools and the materials it used are very simply, and it can be used in very abroad fields, many people take it as an important part in their life. The art of paper cut-out has its own characteristic. For the material it used is very simple, the art of paper cut-out portray the images only through enchasing and connecting the paper. Base on this peculiarity of paper cut-out, this thesis simulates the pattern of paper cut-out, and recur this art form in the computer. At first, we analyze the characteristic of paper cut-out, and sort into four classes: (1) Basic structure pattern. We use the basic structure patterns to figure the physique structure of the objects, which includes four parts: head, body, limbs and trail. Lines, circularities, arcs and some curves belong to this kind of pattern; we can use them to draw the outline of the animals, such as some exaggerated head visualize; (2) Character pattern. We take the character pattern to express the character of the objects that it wants to represent, such as the horn of cattle and sheep, the trail of horse, rat and deer. For the different character of each animal, we build a patterns gallery, and we meet the different request by adjust the parameters of the patterns, for example, the length of the horn and the trail. (3) Special pattern. We use the special pattern the express the facial features on the animal's head. For example, we use(?)to express eyebrow, and we use(?) or(?) to figure the eyes, we use(?) and(?)to denote the nose, and we use(?) or(?) to express the mouth. (4) Decorative pattern. Decorative patterns can let the complicated things and the phantasmagoric natural visions to be consecution and concretion, and can translate them into a more concise and clearer mode. It embodiment the national peculiarity and the regulation of the art of paper cut-out. And then, base on the character of the paper cut-out figure, we create the patterns through the technology of framework, that is, according the structure of the patterns design the frame with style of string, then build the shape by the framework corresponding. We can get the request pattern by adjust the framework's size, thickness, angle and how bend they are. At the end, we get a pattern gallery for paper cut-out pattern. According the material used in paper cut-out, and the symmetry of the pattern is one of the symbol characters of paper cut-out. For this peculiarity, we classify the control parameters of pattern generating into two sorts: position restricts points and figure restricts parameters. The figure restricts parameters can be used to control the shape and size of the patterns. And we can get the location of the symmetry patterns through the computing of the position restricts point by the symmetry axis. At the end, combine the figure restricts parameters we can achieve the rendering of the symmetry patterns. To ensure the patterns are connected to the paper-base, we disconnect the sideline when they are rendering. To prevent the intersection of special patterns and decorate patterns, we give a judgment when they are rendering. Use computer aid to generate the art of paper cut-out, the user can pay more attention on the creation, some work which is take times you may left to the computer. Furthermore, computer assisted generation of paper cut-out images can make it more easier when you want to change some patterns of the paper cut-out image, you just need select the patterns, then you can change or modify them to generated a paper cut-out image with another style. And, computer assisted generation of paper cut-out images make it possible that the art of paper cut-out can be widely used in the area of vignette design, electric cart, advertisement, games and carton. Sum up, the main contributions of this thesis are as follows: Analysis the character of paper cut-out, and classify the patterns by their functions, use the framework technique to generate the patterns of paper cut-out. Classify the control parameters of pattern generating into two sorts: position restricts points and figure restricts parameters. Analysis the connectivity of paper cut-out, ensure that both the patterns itself and patterns each other were not fall apart, and when this happened, the system pop up an admonition dialog box to tell the user you should advert. Create a system of computer aid generation of paper cut-out images.