Touch-Sensitive Surface Click Drag Differentiation
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Solution Overview
Problem
Touch-sensitive surfaces in computer animation systems are prone to user-generated and device-generated input errors, such as jitters and imprecision, which affect the accuracy of interpreting user input and distinguishing between click and drag operations.
Innovation Solution
A touch-sensitive surface that creates a human-unperceivable circle at the point of contact with an initial radius that decreases over time, producing output signals based on the perimeter of this circle and the movement of the touch object, allowing for improved differentiation between click and drag GUI operations by considering the duration of contact and movement within the circle's perimeter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a touch-sensitive surface uses high input precision (e.g., 600 DPI), then measurement precision is improved, but reliability deteriorates due to increased sensitivity to jitters and input errors
Solution Approach 1:
The system dynamically adjusts the tolerance threshold for distinguishing clicks from drags based on the duration of touch contact. As contact time increases, the allowable movement distance increases proportionally, allowing the system to adapt to natural hand movements while filtering out jitters. This dynamic parameter adjustment resolves the contradiction by making the system both precise (filtering small jitters) and reliable (accepting larger movements during sustained contact).
Solution Approach 2:
The patent changes the parameter of tolerance threshold from a fixed value to a time-dependent variable. The threshold is calculated as a function of contact duration, allowing the system to maintain high measurement precision for brief contacts (filtering jitters) while accepting larger movements for prolonged contacts (improving reliability). This parameter transformation enables the system to operate effectively at high DPI without being overly sensitive to input errors.
2Device complexity
If the system distinguishes between clicks and drags using only movement distance, then device complexity is reduced, but measurement precision deteriorates due to inability to filter jitters
Solution Approach 1:
The patent adds a temporal dimension (contact duration) to the traditional spatial measurement (movement distance). By considering both dimensions, the system can distinguish between jitters (small movements with brief contact) and intentional drags (larger movements with prolonged contact). This dimensional expansion maintains relative system simplicity while dramatically improving measurement precision in distinguishing input types.
Solution Approach 2:
The system performs preliminary measurement of contact duration as the touch begins, using this information to establish an appropriate tolerance threshold before evaluating the movement distance. This preliminary action allows the system to set context-appropriate thresholds dynamically, improving precision without requiring complex real-time analysis during the drag operation itself.
Data Source
AI summary
A touch-sensitive surface for a computer animator to create or modify a computer-generated image includes processes for differentiating between click and drag operations. The included processes also beneficially reduce input errors. When a touch object (e.g., finger or stylus) touches the drawing table, information regarding the duration of the touch and the movement of the touch are used to determine whether the touch input represents a (graphical user interface) click or a drag operation.