Ink-Edit: Interactive color-constrained textures editing

Procedural textures are able to generate large and detailed textures on-demand, at rendering time, with minimal memory usage. They are defined by parallel algorithms, which are easily integrated into modern graphics hardware. As a drawback, they may be difficult to control, namely in an interactive and user-friendly manner. In this paper, we define an interactive tool to control the parameters of the procedural model introduced by Grenier et al. [Grenier et al. 2022], which is based on a noise vector field (Figure 1 (a), bottom and middle), and a color map (Figure 1 (a), top). In our interactive tool, the noise is controlled through a small set of parameters in the spectral domain. To control the color map, the user first prescribes the colors (inks) and their proportions (ink volumes in the final result), and then adjusts interactively the adjacency between colors. This is done through a new constrained optimal transport point of view: The colors in the map are regarded as cells of a weighted Voronoi diagram, and the noise distribution is regarded as a probability measure. The ink volumes are automatically enforced as hard constraints of an optimization process during the interactive session, while the user focuses on high-level control over the adjacency of the colors.