Electronic Whiteboard Stroke Erasure via Midpoint Recursion
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Solution Overview
Problem
The existing methods for stroke erasure in electronic whiteboards require extensive calculations, leading to stalling and poor user experience, especially when multiple strokes are erased simultaneously.
Innovation Solution
A method that determines intersecting strokes with an erasing region by traversing collection points, calculating intersection points using midpoint recursion, and inserting approximate intersection points to split and redraw segments not erased by the erasing region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional method traverses all points in each stroke to find intersection points, then calculation accuracy is improved, but calculation complexity increases and system responsiveness deteriorates
Solution Approach 1:
The stroke is segmented into multiple segments based on collection points, and the erasing region is divided into multiple regions. The patent checks intersection points at segment level rather than point level, reducing the number of calculations needed while maintaining accuracy. This segmentation approach allows the system to process strokes more efficiently without sacrificing the precision of intersection detection.
Solution Approach 2:
The patent performs preliminary actions by pre-calculating and storing collection points during stroke drawing, and pre-dividing the erasing region into multiple regions before erasure operation. This preliminary preparation allows the erasure process to proceed more quickly by avoiding real-time calculation of all possible intersection points, thus improving responsiveness while maintaining accuracy through the pre-stored geometric data.
2Measurement precision
If traditional method traverses all points to find intersection points, then calculation accuracy is improved, but system stability deteriorates due to stalling and no response
Solution Approach 1:
By segmenting the stroke into parts defined by collection points and the erasing region into multiple regions, the patent reduces the computational burden during erasure operations. This segmentation prevents system stalling by limiting the number of intersection calculations required, thereby maintaining system responsiveness and stability while still achieving accurate erasure results through the segmented approach.
Solution Approach 2:
The patent applies partial action by only checking intersection points at specific segment boundaries and region intersections rather than traversing all points throughout the entire stroke. This partial checking approach is sufficient for achieving accurate erasure while dramatically reducing computational complexity, preventing system stalling, and maintaining good user experience during erasure operations.
3Productivity
If midpoint recursion is used to calculate intersection points, then calculation efficiency is improved, but measurement precision may be compromised
Solution Approach 1:
The patent uses segmentation to divide the stroke into multiple segments based on collection points, and checks intersection at segment level. This segmentation allows the use of efficient midpoint recursion for calculating intersection points between segments and erasing region boundaries. The segment-based approach provides sufficient precision for erasure purposes while enabling the use of faster calculation methods like midpoint recursion, thus balancing speed and accuracy.
Solution Approach 2:
The patent changes the parameter of intersection detection from point-level precision to segment-level precision. By working with segments defined by collection points rather than individual points, the patent can use midpoint recursion to calculate intersections efficiently. This parameter change maintains adequate measurement precision for the erasure function while significantly improving calculation speed and efficiency.
Data Source
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AI summary
Provided are a stroke erase method, terminal, and computer-readable storage medium; intersecting strokes on a whiteboard that intersect with an erased area are determined; collection points of the intersecting strokes are traversed and it is determined whether the line connecting each two adjacent collection points intersects with the erased area; if the connecting line intersects with the erased area, the approximate intersection point between the connecting line and the erased area is determined by means of midpoint recursion; the intersecting strokes are split into segments according to the approximate intersection points, and the paragraphs not erased by the erased area are drawn; in some implementations, the intersecting strokes are determined directly by means of the strokes on the electronic whiteboard and the erased area.