Handwriting Display Layering for Low-Latency Stroke Rendering
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Solution Overview
Problem
Existing electronic devices experience significant display latency when displaying handwritten content, particularly in continuous touchscreen interactions like image drawing and line drawing, which negatively impacts user experience.
Innovation Solution
Implementing a system-level transparent global layer superimposed on the application layer to draw handwriting strokes independently, allowing for reduced latency by processing these strokes ahead of time using predicted points and maintaining consistency with the application layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the electronic device uses the conventional layer drawing mechanism where each application draws its own content interface layer, then the application can maintain full control over its content rendering, but the display latency increases significantly because the entire layer composition process must wait for all applications to complete their drawing operations
Solution Approach 1:
The patent segments the layer composition process by introducing a global layer that is drawn and composed independently from application layers. The global layer handles system-level drawing operations separately, allowing it to be rendered and composed without waiting for application layer drawing to complete, thereby reducing display latency while maintaining manageable complexity through structured separation of concerns
Solution Approach 2:
The global layer performs drawing operations in advance and independently of the application layer composition process. By pre-drawing content on the global layer before application layers are fully rendered, the system eliminates the sequential waiting time that causes display latency, achieving faster overall rendering without significantly increasing system complexity
2Loss of time
If the electronic device draws writing strokes on the application layer, then the strokes are integrated with the application content, but the display latency increases because the strokes must be drawn as part of the application's rendering pipeline
Solution Approach 1:
The patent segments the drawing target into two distinct layers: the global layer for system-level writing strokes and the application layer for application-specific content. This segmentation allows writing strokes to be drawn independently on the global layer without being constrained by the application's rendering pipeline, significantly reducing stroke display latency while maintaining visual consistency through proper layer composition and transparency settings
Solution Approach 2:
The global layer acts as an intermediary between the input system and the application layer. It receives writing stroke input events directly and renders them independently, then composes with application layers to produce the final display output. This intermediary approach decouples stroke rendering from application rendering, reducing latency while preserving visual integration through the composition process
3Loss of time
If the electronic device creates a system-level global layer for handwriting, then the display latency is reduced through independent drawing, but the system complexity increases due to additional layer management requirements
Solution Approach 1:
The global layer is designed as a universal, system-level component that handles all handwriting and drawing operations across different applications uniformly. This multi-functional approach consolidates layer management logic into a single system-level mechanism rather than requiring each application to implement its own handwriting layer management, reducing touch latency through centralized optimization while keeping system complexity manageable through reuse and standardization
4Productivity
If the electronic device uses traditional application-specific drawing methods, then each application can customize its drawing behavior, but the overall system performance deteriorates due to repeated processing of similar drawing operations across multiple applications
Solution Approach 1:
The global layer provides a universal drawing mechanism that handles common handwriting operations efficiently for all applications. This system-level approach improves productivity by processing similar drawing operations once at the global layer rather than repeatedly in each application. Applications that need custom drawing behavior can still do so by drawing on the application layer, which composes with the global layer, thus preserving adaptability while gaining overall system efficiency
Data Source
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AI summary
This application discloses a method for displaying handwritten content and an electronic device, and relates to the field of terminal technologies, to reduce a display latency of the handwritten content in a process of handwriting the content on a content interface by a user, improve a touch latency of display, and improve user experience. In this solution, when the user performs a handwriting operation on the content interface, such as line drawing, writing, circling, and marking, the electronic device may create a system-level transparent layer, for example, a global layer, that is independent of a layer at which the content interface is located and that is superimposed on the layer at which the content interface is located, perform stroke estimate based on the handwriting operation of the user and a historical writing stroke, and draw, based on a touch point corresponding to the handwriting operation of the user and predicted points, a corresponding writing stroke at the global layer.