Set the interpolation method

# imagesetinterpolation

(PHP 5 >= 5.5.0, PHP 7, PHP 8)

imagesetinterpolation — Set the interpolation method

### Description

imagesetinterpolation(GdImage `$image`, int `$method` = `IMG_BILINEAR_FIXED`): bool

Sets the interpolation method, setting an interpolation method affects the rendering of various functions in GD, such as the imagerotate() function.

### Parameters

`image`

  A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor().

`method`

  The interpolation method, which can be one of the following:

  - `IMG_BELL`: Bell filter.
  - `IMG_BESSEL`: Bessel filter.
  - `IMG_BICUBIC`: Bicubic interpolation.
  - `IMG_BICUBIC_FIXED`: Fixed point implementation of the bicubic interpolation.
  - `IMG_BILINEAR_FIXED`: Fixed point implementation of the bilinear interpolation (`default (also on image creation)`).
  - `IMG_BLACKMAN`: Blackman window function.
  - `IMG_BOX`: Box blur filter.
  - `IMG_BSPLINE`: Spline interpolation.
  - `IMG_CATMULLROM`: Cubic Hermite spline interpolation.
  - `IMG_GAUSSIAN`: Gaussian function.
  - `IMG_GENERALIZED_CUBIC`: Generalized cubic spline fractal interpolation.
  - `IMG_HERMITE`: Hermite interpolation.
  - `IMG_HAMMING`: Hamming filter.
  - `IMG_HANNING`: Hanning filter.
  - `IMG_MITCHELL`: Mitchell filter.
  - `IMG_POWER`: Power interpolation.
  - `IMG_QUADRATIC`: Inverse quadratic interpolation.
  - `IMG_SINC`: Sinc function.
  - `IMG_NEAREST_NEIGHBOUR`: Nearest neighbour interpolation.
  - `IMG_WEIGHTED4`: Weighting filter.
  - `IMG_TRIANGLE`: Triangle interpolation.

### Return Values

Returns `true` on success or `false` on failure.

### Changelog

Version | Description
--- | ---
8.0.0 | `image` expects a GdImage instance now; previously, a valid `gd` resource was expected.

### Examples

Example #1 imagesetinterpolation() example

`<?php
// Load an image
$im = imagecreate(500, 500);
// By default interpolation is IMG_BILINEAR_FIXED, switch
// to use the 'Mitchell' filter:
imagesetinterpolation($im, IMG_MITCHELL);
// Continue to work with $im ...
?>`

### Notes

Changing the interpolation method affects the following functions when rendering:

- imageaffine()
- imagerotate()

### See Also

- imagegetinterpolation() - Get the interpolation method

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