imagesetinterpolation

(PHP 5 >= 5.5.0, PHP 7)

imagesetinterpolationSet the interpolation method

Descrierea

imagesetinterpolation ( resource $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.

Parametri

image

O resursă - imagine, întoarsă de una din funcțiile de creare a imaginilor, cum ar fi 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.

Valorile întoarse

Întoarce valoarea true în cazul succesului sau false în cazul eșecului.

Exemple

Example #1 imagesetinterpolation() example

<?php
// Load an image
$im imagecreate(500500);

// By default interpolation is IMG_BILINEAR_FIXED, switch 
// to use the 'Mitchell' filter:
imagesetinterpolation($imIMG_MITCHELL);

// Continue to work with $im ...
?>

Note

Changing the interpolation method affects the following functions when rendering:

A se vedea și

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User Contributed Notes 1 note

up
-1
shaun at slickdesign dot com dot au
6 years ago
Setting the interpolation does not carry through to any images created by imageaffine() or imagerotate(). It defaults to IMG_BILINEAR_FIXED and would need to be set on each generated image as required.

<?php
imagesetinterpolation
( $image, IMG_NEAREST_NEIGHBOUR );

// Rotated using IMG_NEAREST_NEIGHBOUR
$rotated = imagerotate( $image, 45, $transparent );

// Rotated using IMG_BILINEAR_FIXED
$rotated_again = imagerotate( $rotated, 45, $transparent );
?>

Setting the interpolation to IMG_NEAREST_NEIGHBOUR can help to preserve details and prevent sampling issues when rotating an image at 90 degree increments, including when rotating clockwise.

<?php
// Rotated image can appear blurred and on a slight angle.
$rotated = imagerotate( $image, -360, $transparent );

// Similar to starting Image although it may still show a background or be on a slight angle.
imagesetinterpolation( $image, IMG_NEAREST_NEIGHBOUR );
$rotated = imagerotate( $image, -360, $transparent );
?>
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