Collaborative Whiteboard Canvas Sync With Edge-Triggered Re-Rendering

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Solution Overview

Problem

Existing display technologies face inefficiencies and scalability issues when multiple terminals collaborate to update a canvas that expands infinitely, leading to prolonged redrawing times and potential freezing due to the need to recalculate and redraw canvas content with each movement.

Innovation Solution

Implementing a method where the following terminal uses a multiple-size canvas, such as a double-size canvas, and only re-renders content when the canvas edges coincide with the application interface edges during movements, avoiding the need to clear and redraw the entire canvas with each movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If multiple terminals synchronize display content in real-time, then display consistency is improved, but system resource consumption increases

Engineering Contradiction:
Improvedisplay consistencyVSAvoidsystem resource consumption
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent extracts and identifies only the changed regions (difference images) between master and slave terminal displays, rather than transmitting or processing entire display frames. This selective extraction of changed portions reduces the amount of data that needs to be synchronized across terminals, thereby maintaining display consistency while reducing computational and communication resource consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The display content is segmented into multiple regions, with only the changed regions being identified and transmitted for synchronization. The display area is divided into multiple blocks, and the system selectively updates only those blocks that have changed, rather than updating the entire display content on all terminals simultaneously.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If difference images are calculated and transmitted for each terminal, then synchronization precision is improved, but communication overhead increases

Engineering Contradiction:
Improvesynchronization precisionVSAvoidcommunication overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent merges the difference image calculation and transmission process into a unified efficient workflow. Instead of calculating and transmitting separate difference images for each terminal independently, the system calculates difference images based on the master terminal's display changes and efficiently distributes them to multiple slave terminals, reducing redundant communication overhead while maintaining synchronization precision.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the master terminal calculates difference images for all slave terminals, then synchronization accuracy is improved, but processing time increases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by calculating difference images based on the master terminal's display changes before actual synchronization is needed. The difference image calculation is optimized to quickly identify changed regions, and this preliminary calculation enables efficient subsequent transmission and application of updates across all slave terminals without delays.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4325344B1Multi-terminal collaborative display update method and apparatus
Publication Date: 2026.04.29 GUANGZHOU SHIYUAN ELECTRONICS CO LTD
  • EP4325344B1 patent drawingFigure 1
  • EP4325344B1 patent drawingFigure 2~3a
  • EP4325344B1 patent drawingFigure 3b~5

AI summary

The present disclosure discloses a method and device for multiple-terminal collaboratively updating a displayed content. The method includes: displaying, by the first terminal, the first application interface of the first collaborative whiteboard application, where the first collaborative whiteboard application and the second collaborative whiteboard application of the second terminal are in a collaborative mode, where the second terminal displays the second application interface of the second collaborative whiteboard application; receiving a controlling parameter transmitted by the second terminal, where the controlling parameter is generated by the second terminal when receiving a controlling operation performed on the second application interface; and updating, by the first terminal, a content of the first application interface based on the controlling parameter, where the controlling operation is determined as a moving operation, the first canvas is moved based on the controlling parameter, and when an edge of the first canvas coincides with an edge of the first application interface in the same direction, re-rendering, by the first terminal, the content in the first canvas. The present disclosure solves the technical problem that the following terminal is difficult to follow when the canvas of the followed terminal expands infinitely in the prior art.