resize

The C++ interface for resize. More...

array	resize (const float scale, const array &image, const char method='L')
	Resize an image based on a scaling factor (uniform) More...
array	resize (const float scale_x, const float scale_y, const array &image, const char method='L')
	Resize an image based on two scale factors (non-uniform) More...
array	resize (const unsigned height, const unsigned width, const array &image, const char method='L')
	Resize an image to a specified width and height in pixels. More...

Detailed Description

The C++ interface for resize.

The resize function scales an image up or down based on a constant scaling factor or an explicit new size. resize provides two methods for this operation, nearest neighbor interpolation and bilinear interpolation.

The following examples illustrate the difference between the two types of interpolation:

float h_in[]  = {1, 2, 3, 4};
array in(2, 2, h_in);
// in = 1 3
//      2 4

array out = resize(2.0f, in, 'N');

// out = 1 1 3 3
//       1 1 3 3
//       2 2 4 4
//       2 2 4 4

array bi_out = resize(2.0f, in, 'L');

// out = 1.00 1.50 2.50 3.00
//       1.25 1.75 2.75 3.25
//       1.75 2.25 3.25 3.75
//       2.00 2.50 3.50 4.00

Function Documentation

array af::resize	(	const float	scale,
		const array &	image,
		const char	method = 'L'
	)

Resize an image based on a scaling factor (uniform)

// resize an image to half size along each dimension
// (downsize to 1/4 of area)
// retains original aspect ratio

array img_out = resize(0.5f, img_in);

Parameters

[in]	scale	uniform scale factor (e.g. "1.1" scales image up 10%, 0.6 scales image down to 60%). Height and width scaled uniformly.
[in]	image	the image to resize
[in]	method	interpolation type ('N' Nearest | 'L' bilinear)

Returns

resized image

array af::resize	(	const float	scale_x,
		const float	scale_y,
		const array &	image,
		const char	method = 'L'
	)

Resize an image based on two scale factors (non-uniform)

// Resize an image using two scaling factors
// (does not retain original aspect ratio)
array img_out = resize(0.33, 0.66, img_in);

Parameters

[in]	scale_x	scale factor for first dimension (>= 0)
[in]	scale_y	scale factor for second dimension (>= 0)
[in]	image	the image to resize
[in]	method	interpolation type ('N' Nearest Neighbor | 'L' linear)

Returns

resized image

array af::resize	(	const unsigned	height,
		const unsigned	width,
		const array &	image,
		const char	method = 'L'
	)

Resize an image to a specified width and height in pixels.

// Resize an image to a specific size, ignoring original aspect ratio
array img_out = resize(480, 640, img_in);

Parameters

[in]	height	output height in pixels
[in]	width	output width in pixels
[in]	image	the image to resize
[in]	method	interpolation type ('N' Nearest | 'L' bilinear)

Returns

resized image