Funções da GD
PHP Manual

imagescale

(PHP 5 >= 5.5.0, PHP 7)

imagescaleScale an image using the given new width and height

Descrição

resource imagescale ( resource $image , int $new_width [, int $new_height = -1 [, int $mode = IMG_BILINEAR_FIXED ]] )

imagescale() scales an image using the given interpolation algorithm.

Parâmetros

image

Um resource de imagem, retornado por funções de criação de imagens, como imagecreatetruecolor().

new_width

The width to scale the image to.

new_height

The height to scale the image to. If omitted or negative, the aspect ratio will be preserved.

Cuidado

You should always provide the height if using PHP 5.5.18 or earlier, or PHP 5.6.2 or earlier, as the aspect ratio calculation was incorrect.

mode

One of IMG_NEAREST_NEIGHBOUR, IMG_BILINEAR_FIXED, IMG_BICUBIC, IMG_BICUBIC_FIXED or anything else (will use two pass).

Nota: IMG_WEIGHTED4 is not yet supported.

Valor Retornado

Return the scaled image resource on success ou FALSE em caso de falha.

Changelog

Versão Descrição
5.5.19/5.6.3 The calculation of the height if new_height was negative or omitted was fixed; prior to these versions, the aspect ratio was not maintained correctly.


Funções da GD
PHP Manual