imagesetinterpolation

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

imagesetinterpolationSet the interpolation method

Beschreibung

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.

Parameter-Liste

image

Ein GdImage-Objekt, das von einer der Funktionen zur Bilderzeugung, z. B. imagecreatetruecolor(), zurückgegeben wurde.

method

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

Rückgabewerte

Gibt bei Erfolg true zurück. Bei einem Fehler wird false zurückgegeben.

Changelog

Version Beschreibung
8.0.0 image erwartet nun eine GdImage-Instanz; vorher wurde eine gültige gd-Ressource erwartet.

Beispiele

Beispiel #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 ...
?>

Anmerkungen

Changing the interpolation method affects the following functions when rendering:

Siehe auch

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User Contributed Notes 1 note

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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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