Comp2DShapesFocal.cpp File Reference

compare polygons with specific focal points More...

#include "Comp2DShapesFocal.h"

Functions
Vector2D	parse_focal_point (const std::string &focal_input, bool verbose=false)
	Parse focal point from either a file path or inline coordinates.
int	main (int argc, char **argv)
	Main function for comparing 2D shapes with specified focal points.
bool	parse_args (int argc, char **argv, std::string *file1, std::string *focal1, std::string *file2, std::string *focal2, int *disttype, double *microns_per_pixel1, double *microns_per_pixel2, bool *verbose)
	Parse command-line arguments for Comp2DShapesFocal.

Detailed Description

compare polygons with specific focal points

Author

Patrice Koehl

Yossi Bokor Bleile

Date

December 2025

Version

1.1

Copyright

BSD 3-Clause License.

Function Documentation

main()

int main	(	int	argc,
		char **	argv )

Main function for comparing 2D shapes with specified focal points.

This program compares two 2D polygons using various distance metrics, with user-specified focal points for each polygon. The polygons are shifted so that their focal points are at the origin before comparison, allowing for focal-point-relative shape analysis.

The program supports multiple distance metrics:

• Fréchet distance: Measures curve similarity (minimum leash length)
• Ellipse-based: Compares fitted ellipse properties (inscribed, inscribing, least-squares)
• Curvature-based: Willmore energy and Wasserstein distance on curvature distributions
• Persistence diagrams: Topological comparison using persistent homology

Parameters

argc	Number of command-line arguments
argv	Array of command-line argument strings

Returns

0 on success, 1 on failure

See also

parse_args() for command-line argument details

parse_focal_point() for focal point specification format

parse_args()

bool parse_args	(	int	argc,
		char **	argv,
		std::string *	file1,
		std::string *	focal1,
		std::string *	file2,
		std::string *	focal2,
		int *	disttype,
		double *	microns_per_pixel1,
		double *	microns_per_pixel2,
		bool *	verbose )

Parse command-line arguments for Comp2DShapesFocal.

Parses command-line arguments for the Comp2DShapesFocal program, extracting input files, focal points, distance type, microns per pixel settings, and verbose flag.

Parameters

	argc	Argument count from main()
	argv	Argument vector from main()
[out]	file1	Path to first input polygon file (set by -i1 flag)
[out]	focal1	Focal point for first polygon - file path or "x,y" format (set by -f1 flag)
[out]	file2	Path to second input polygon file (set by -i2 flag)
[out]	focal2	Focal point for second polygon - file path or "x,y" format (set by -f2 flag)
[out]	disttype	Distance type flag (set by -d flag): 0: Fréchet distance - measures similarity between curves, representing the minimum leash length needed for a person walking a dog along each curve 1: Ellipse-based distances - compares aspect ratios of inscribed, inscribing, and least-squares fitted ellipses 2: Curvature-based distances - includes Willmore energy (bending energy) and Wasserstein distance between curvature distributions 3: 2-Wasserstein distance between persistence diagrams - topological shape descriptor based on persistent homology 4: All distances - computes all of the above metrics
[out]	microns_per_pixel1	Microns per pixel conversion for polygon 1 (set by -mpp1 or -mpp flag, default: 1.0)
[out]	microns_per_pixel2	Microns per pixel conversion for polygon 2 (set by -mpp2 or -mpp flag, default: 1.0)
[out]	verbose	Enable verbose output (set by -v or –verbose flag, default: false)

Returns

true if arguments were parsed successfully, false otherwise

parse_focal_point()

Vector2D parse_focal_point	(	const std::string &	focal_input,
		bool	verbose = false )

Parse focal point from either a file path or inline coordinates.

This function accepts either a file path containing focal point coordinates or a string with inline coordinates in the format "x,y". If a valid file exists at the path, it reads the coordinates from the file. Otherwise, it parses the string as inline coordinates.

Parameters

focal_input	String containing either a file path or inline coordinates (e.g., "698.678,816.662")
verbose	If true, prints debug information during parsing (default: false)

Returns

Vector2D containing the parsed focal point coordinates

Exceptions

std::exit(1)

if the focal point cannot be parsed or has fewer than 2 coordinates