distance_field.c File Reference

Code for generating our distance fields (. More...

#include "edtaa3func.h"

Include dependency graph for distance_field.c:

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Functions
double *	make_distance_mapd (double *data, unsigned int width, unsigned int height, double *vmax)
	Like the original: perform a Euclidean Distance Transform on the input and normalize to [0,1], with a value of 0.5 on the boundary.
float *	make_distance_mapbf (unsigned char *img, unsigned int width, unsigned int height, double *vmax)
	Perform a Euclidean Distance Transform on the input and normalize to [0,1], with a value of 0.5 on the boundary.

Detailed Description

Code for generating our distance fields (.

See also

font.c). Based on the corresponding file in https://github.com/rougier/freetype-gl

Definition in file distance_field.c.

Function Documentation

make_distance_mapbf()

float * make_distance_mapbf	(	unsigned char *	img,
		unsigned int	width,
		unsigned int	height,
		double *	vmax )

Perform a Euclidean Distance Transform on the input and normalize to [0,1], with a value of 0.5 on the boundary.

Parameters

	img	Pixel values, row-major order.
	width	Number of columns.
	height	Number of rows.
[out]	vmax	The underlying distance value corresponding to +1.0.

Returns

Allocated distance field, values ranging from 0 (innermost) to 1 (outermost). The reason for the inversion (relative to make_distance_mapd and the "signed distance" concept) is so that these can be pasted together in a texture atlas with a buffer of 0.0 values representing "completely outside".

Definition at line 127 of file distance_field.c.

make_distance_mapd()

double * make_distance_mapd	(	double *	data,
		unsigned int	width,
		unsigned int	height,
		double *	vmax )

Like the original: perform a Euclidean Distance Transform on the input and normalize to [0,1], with a value of 0.5 on the boundary.

Parameters

	data	width*height values, row-major order. Positive values are object pixels. Negative/zero values are background pixels.
	width	Number of columns.
	height	Number of rows.
[out]	vmax	The underlying distance value corresponding to +1.0.

Returns

Allocated distance field, values ranging from 0 (farthest inside) to 1 (greatest distance).

Definition at line 60 of file distance_field.c.