Content-aware processing of vector images

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In computer graphics, two-dimensional images are typically represented in one of two ways. Raster images are grids of colour samples; they are the kind that everyday computer users are most familiar with, because digital photographs are represented in this way. In the world of professional graphic design and illustration, however, vector images are also ubiquitous and important. A vector image is more like a drawing: it is made up of a sequence of shapes that are filled in and outlined in solid or gradually changing colours. Because they represent objects in an image as precise geometry, vector images have the advantage that they can be scaled arbitrarily without any loss in quality. Vector images are common on computer desktops and the screens of mobile devices (where they are first "rasterized", so that they can be displayed as pixels), in print advertising and signage, and on clothing. They are also used to represent characters and backgrounds in many video games. Today there are sophisticated algorithms that can perform intelligent analysis and transformations of digital photographs. Your camera can detect when your subject is smiling, and compose complex photographs in various ways from multiple independent exposures. Desktop image editing software like Adobe Photoshop can dynamically reshape digital images by making imperceptible changes to background objects, seamlessly alter the contents of photographs, and even alter colours or materials of individual objects in photographs. In comparison, tools for editing vector images still operate at a fairly low level of abstraction. These tools are more literal: they are simply not as able to make sense of the structure and content of the image being edited. This is unfortunate, especially given that a vector image contains a significant amount of geometric information that is not being exploited, such as the sizes and shapes of objects and the relationships between them. This research investigates ways of representing and manipulating vector images that exploit their inherent structure, giving graphic designers some of the power over vector images that photographers now enjoy with raster images. I will explore the analysis of vector line art in order to support more intelligent colouring operations, which could be used in comic creation. I will look at representations of shapes and textures that permit large, non-repeating blocks of texture to be created automatically from small examples. And I will develop techniques for dynamically reshaping a vector image's canvas without distorting the shapes of the objects in that image. This work promises to revitalize contemporary research into the capabilities of vector graphics, and empower expert designers and illustrators with new tools that make them more effective, more expressive, and more creative.