2D Polygon Clipping Against Rectangular View Window
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polygon clipping methods for computer graphics and geographic information systems face inefficiencies when dealing with complex convex-concave polygons, leading to increased spatial and temporal complexity and reduced drawing efficiency due to redundancy beyond the window area.
Innovation Solution
A method that selects the first internal point of a 2D polygon as the starting point to analyze spatial relationships between polygon edges and a rectangular view window, clipping off invalid areas by traversing points and determining intersection points to create a vertex set for efficient clipping, applicable to both concave and convex polygons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polygon clipping is performed using traditional methods, then complete polygon data is processed, but drawing time and space complexity increase due to invalid areas beyond the window
Solution Approach 1:
The patent extracts only the valid portion of the polygon that lies within the rectangular view window by determining intersection points between polygon edges and window boundaries. This extraction principle eliminates the need to process invalid areas outside the window, directly reducing drawing time and improving efficiency.
Solution Approach 2:
The patent segments the polygon into multiple parts based on its spatial relationship with the view window. By dividing the polygon into valid and invalid portions and processing only the valid segments, the algorithm reduces computational complexity while maintaining complete polygon coverage within the window.
2Manufacturing precision
If traditional polygon clipping methods are used, then all polygon edges are processed, but space complexity increases due to storing redundant vertex data
Solution Approach 1:
The patent extracts only the necessary vertex coordinates that define the clipped polygon within the view window. By storing only these essential coordinates rather than complete polygon data, the algorithm reduces space complexity while maintaining precise clipping accuracy through systematic determination of intersection points.
Data Source
AI summary
A method for clipping a two-dimensional (2D) polygon against a rectangular view window, including inputting a vertex coordinate set A′ of the 2D polygon and coordinates of the rectangular view window; creating a search circular linked list A and a vertex set B of an overlapping region; numbering vertices and edges of the 2D polygon and the rectangular view window; and storing vertices in the set A′ into the list A; obtaining spatial relationship based on relative position between vertices of the 2D polygon and the rectangular view window; performing different operations according to the spatial relationship; adding the starting point A0 in the list A to the vertex set B; allowing a pointer to point to the starting point A0; determining whether a current vertex of the 2D polygon pointed by the pointer is within the rectangular view window; and clipping the 2D polygon.