This article presents an extension of the Through-the-Lens Camera Control approach proposed by Gleicher and Witkin. It first provides a higher means of control on the camera by using virtual composition primitives and second offers a means for through-the-lens interaction with both the location of the objects in the scene and the lighting. By setting properties on the composition primitives, users convey constraints to enforce the positioning of the camera, the objects and the lights directly through the lens. The paper presents how to express all three problems of indirect camera, object and light interaction in a consistent way and provides some first results. The solving techniques rely on the expression of the image Jacobian coupled with a constrained optimizer based on Quadratic Programming. The Jacobian expresses the relation between the user input and the possible degrees of freedom on the entity to manipulate; in order to avoid solving failures that are delicate to manage in user interfaces, we propose a mass-spring interaction model. As a result, the user should be able concentrate on higher level properties such as composition, balance and unity through a natural and effective interaction process.
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