A Layered Canvas Synchronization Mechanism for an Adaptable Presentation System
伊藤栄俊, 大囿忠親, 新谷虎松


An adaptable presentation is expanded an interactive presentation, that cognizes the presen- tation state, and that shows the materials, slides, and contents. An adaptable presentation re- quires the slide relationship that has the connection between slides. Therefore, an adaptable presentation requires too many objects. Too many objects in a canvas degrade rendering performance. We called this problem a canvas redrawing problem. We developed a layered canvas synchronization mechanism to solve the canvas redrawing problem for an adaptable presentation. A layered canvas synchronization mechanism improved the performance with layered canvases. Redistribution of drawing objects to each layered canvas suppresses the cost and realize the real-time rendering on a web application. The existing layered canvas algorithms remained a problem when we updated objects at the same time. We proposed a batch algorithm, that is a novel way of layered canvases. The experimental evaluation indicated the effectiveness of the batch algorithm and our system. Our contribution is that layered canvases solved the canvas redrawing problem and that the batch algorithm enabled us to update 100 objects at the same time.