Handwriting Trace Rendering via Central Line Segmentation

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Solution Overview

Problem

Current handwriting input systems on tablet PCs fail to produce a smooth, stylized handwriting trace, leading to a lagged user experience due to unsatisfactory curve drawing methods.

Innovation Solution

A method that determines stroke width and position information to set a central line for each stroke, calculates filling gray values based on longitudinal stroke widths and slopes, and displays pixels accordingly, avoiding complex curve drawing to accelerate processing and provide a smooth experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If curve fitting is used to compute a smooth curve closest to all sampling points, then the handwriting trace becomes smooth and stylized, but the drawing speed becomes slow and lags behind user handwriting speed

Engineering Contradiction:

Improvesmoothness of handwriting traceVSAvoiddisplay speed of handwriting trace

Core Design Contradiction:

ShapeVSSpeed

Solution Approach 1:

The patent segments the handwriting trace into multiple stroke segments based on sampling points. Each segment is processed independently to determine its central line and stroke width, avoiding the need to process the entire trace as a single complex curve. This segmentation enables faster processing while maintaining smooth appearance through localized curve approximation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial curve fitting only where necessary - specifically, it fits curves to segments between sampling points rather than fitting a single complex curve through all points. This partial action approach achieves sufficient smoothness for visual display while dramatically reducing computational complexity and processing time.

Inventive Principle:

Principle #16Partial or excessive action

2Shape

If complex curve drawing functions are used to achieve smooth handwriting trace, then the trace quality improves, but the system overhead increases and processing becomes slower

Engineering Contradiction:

Improvequality of handwriting traceVSAvoidsystem overhead for curve drawing

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent extracts only the essential elements needed for smooth display - the central line and stroke width of each segment - without using complex graphics system curve drawing functions. By taking out only the necessary geometric parameters and rendering them directly, the system achieves trace quality without the overhead of complex curve fitting algorithms.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using complex curve drawing functions to generate smooth traces, the patent inverts the approach by directly calculating simplified geometric representations (central lines and widths) and rendering them. This inversion from complex-to-simple achieves the same visual quality with much lower system overhead.

Inventive Principle:

Principle #13The other way round (Inversion)

3Speed

If straight line connection of sampling points is used, then the processing speed is fast, but the handwriting trace does not look smooth or stylized

Engineering Contradiction:

Improveprocessing speed of handwriting traceVSAvoidsmoothness of handwriting trace

Core Design Contradiction:

SpeedVSShape

Solution Approach 1:

The patent introduces curvature by calculating a central line that smoothly connects sampling points rather than using straight lines. The central line computation incorporates curvature information to create smooth transitions between points, while the stroke width varies along this curved path to maintain the stylized appearance of handwriting.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Loss of time

If immediate display of handwriting trace is implemented, then user experience improves, but complex curve processing is required which slows down the system

Engineering Contradiction:

Improvedisplay latency of handwriting traceVSAvoidprocessing efficiency of the system

Core Design Contradiction:

Loss of timeVSProductivity

Solution Approach 1:

The patent performs preliminary calculations of the central line and stroke width for each segment as data is being collected, rather than waiting to process all points after handwriting is complete. This preliminary action enables immediate display of smooth, stylized traces without requiring complex post-processing, thus reducing display latency while maintaining processing efficiency.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9183428B2Method and device for implementing original handwriting trace, and electronic device

Publication Date: 2015.11.10 BEIJING ERENEBEN INFORMATION TECH

AI summary

The present invention provides a method and device for implementing original handwriting trace, and an electronic device. The method comprises: continuously sampling handwriting trace in time order, and detecting location information and the actual stroke widths at the sampling points; for every two adjacent sampling points, determining the former point as the starting sampling point, determining the latter point as the ending sampling point, using a line connecting the two points as the center line of the stroke between the two sampling points, obtaining location information of and the corresponding longitudinal stroke width at each point on the center line, and determining, according to the location information of and the corresponding longitudinal stroke width at each point on the center line, the fill gray value of each pixel in the stroke; and filling, according to the fill gray values, the corresponding pixels, and displaying the pixels. In this manner, graphic processing of the system is avoided, thereby accelerating the stylized trace processing, and bringing smooth writing experience to users.