Abstract: In graphic design, the layout is a result of the interaction between the design elements in the foreground and the background images. However, prevalent researches in the literature have primarily focused on enhancing the quality of layout generation algorithms, overlooking the interaction and controllability that are essential for designers when applying these methods in real-world situations. This paper proposes a user-centered layout design system, Iris, which provides designers with an interactive environment to expedite the workflow, and this environment encompasses the features of user-constraints specification, layout generation, custom editing, and final rendering. To satisfy the multiple constraints specified by designers, we introduce a novel generative model, Multi-constrained LayoutVQ-VAE, for advancing layout generation under both intra-domain and inter-domain constraints. Qualitative and quantitative experiments on our proposed model indicate that it outperforms or is comparable to prevalent state-of-the-art models in multiple aspects. User studies on Iris further demonstrate that the system significantly enhances design efficiency while also achieving human-like layout designs.