Text prompting is an indirect way to generate posters: users must compress an inherently two-dimensional layout intent into a one-dimensional string of words. A new paper posted to Hugging Face, From Prompting to Composing: A Spatial Canvas Interface for Poster Generation, argues for a more direct approach.
The authors introduce a Spatial Canvas Interface in which generation intent is composed in space rather than described in prose. It supports four complementary binding types: semantic binding, which ties a textual concept to a target region; identity binding, which links a reference image to a region so its visual identity is preserved; text binding, which specifies an exact string and where it should appear; and pixel binding, which places visual content that must be kept intact. Text Specifications handle individual elements and global appearance.
Built on this interface is Compo, a poster generation model adapted from a pretrained image editing model without task-specific architecture design. Bounding boxes, reference images and textual identifiers are rendered directly onto the canvas to form a single unified image input. Compo supports direct inference, where users build the canvas themselves, and an agentic mode in which a high-level request is automatically translated into a planned Spatial Canvas.
To train the model, the team developed a scalable pipeline that automatically constructs supervision data for the different binding types and their combinations, allowing efficient adaptation without training a dedicated poster generator from scratch. They also introduce a benchmark that measures adherence to individual binding types and to their joint composition.
Experiments reported in the paper indicate that Compo achieves stronger compositional controllability than both general-purpose image generation models and dedicated poster generation systems, while maintaining high visual quality. The authors frame the contribution as decoupling intent specification from visual generation, shifting poster generation from prompting toward composing.