imagesetinterpolation

Set the interpolation method

&reftitle.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.

&reftitle.parameters;

&gd.image.description;

`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.

&reftitle.returnvalues;

&return.success;

&reftitle.changelog;

&Version; | &Description;
&gd.changelog.image-param;

&reftitle.examples;

### `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 ...
    ?>

&reftitle.notes;

Changing the interpolation method affects the following functions when rendering:

- `imageaffine`

- `imagerotate`

&reftitle.seealso;

- `imagegetinterpolation`