Guide Line Snapping Using Perpendicular Distance Bounding
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Solution Overview
Problem
Current cursor snapping mechanisms in computer-assisted drawing applications face significant processing workloads due to the need to clip and process all potential guide lines within a snapping tolerance, even when most lines are not near the cursor location, leading to reduced cursor tracking rate and guide line display speed.
Innovation Solution
The solution focuses on efficiently bounding the search for guide lines by calculating perpendicular reference distances from the cursor location to guide lines, using a multi-map data structure and binary search to identify only those guide lines within the snapping tolerance, thereby reducing the number of lines that need to be processed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all potential guide lines are clipped against the clipping rectangle to determine snapping locations, then complete accuracy in identifying all possible guide lines is achieved, but the processing workload increases dramatically reducing cursor tracking rate
Solution Approach 1:
The patent segments the large set of all potential guide lines into smaller subsets based on spatial proximity to the cursor. By dividing the comprehensive guide line set into manageable groups (those within snapping tolerance vs. those outside), the system processes only relevant segments, maintaining accuracy while reducing overall processing workload.
Solution Approach 2:
The patent applies partial action by clipping and processing only those guide lines that fall within the clipping rectangle and snapping tolerance of the cursor, rather than processing all M*N potential guide lines. This selective processing approach performs just enough action to identify relevant guide lines without the excessive computation of examining every possible guide line.
2Productivity
If the clipping rectangle bounds space around the cursor to limit processing, then the number of guide lines to process is reduced, but guide lines outside the rectangle cannot be evaluated for snapping
Solution Approach 1:
The patent applies local quality by creating a clipping rectangle with snapping tolerance that focuses processing resources on the local region around the cursor where guide lines are actually relevant. The clipping rectangle's boundaries are strategically positioned to include only those guide lines that could potentially snap to the cursor, giving different processing treatment to different spatial regions.
3Reliability
If M*N guide lines are clipped before determining snapped location, then all potential guide lines are considered, but processing time increases even when most lines are not near the cursor
Solution Approach 1:
The patent extracts from the complete set of M*N potential guide lines only those that fall within the clipping rectangle and snapping tolerance. By taking out the irrelevant guide lines that are clearly not near the cursor, the system maintains reliable snapping detection for relevant lines while eliminating wasted processing time on distant lines.
Solution Approach 2:
The patent performs preliminary action by using the clipping rectangle to pre-filter guide lines before the detailed snapping determination process. This preliminary filtering step eliminates obviously irrelevant guide lines early, so that the more time-consuming snapping calculations are performed only on guide lines that have a chance of being relevant.
Data Source
AI summary
Apparatus, systems, and methods may operate to determine a substantially perpendicular current distance from a cursor guide line that passes through a given current cursor location, to a reference point. Additional activity may include determining candidate guide lines that comprise a subset of a larger group of guide lines and that are associated with at least one drawing object, each one of the subset having a substantially perpendicular reference distance to the reference point that is within a range defined by a snapping tolerance and the current distance. A snapping location can be displayed on the closest one of the subset as measured from the current cursor location. Additional apparatus, systems, and methods are disclosed.