imagesetinterpolation

Set the interpolation method

Description

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

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