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 );
?>
imagesetinterpolation
(PHP 5 >= 5.5.0, PHP 7)
imagesetinterpolation — Set the interpolation method
설명
bool imagesetinterpolation
( resource
$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.
인수
-
image -
imagecreatetruecolor() 등의 이미지 생성 함수에서 반환한 이미지 자원.
-
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.
-
반환값
성공 시 TRUE를, 실패 시 FALSE를 반환합니다.
예제
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 ...
?>
주의
Changing the interpolation method affects the following functions when rendering:
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User Contributed Notes 1 note
shaun at slickdesign dot com dot au ¶
7 years ago
