imagescale

(PHP 5 >= 5.5.0, PHP 7)

imagescale — Scale an image using the given new width and height

说明

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.

参数

image

由图象创建函数(例如imagecreatetruecolor())返回的图象资源。

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.

Caution

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).

Note: IMG_WEIGHTED4 is not yet supported.

返回值

Return the scaled image resource on success 或者在失败时返回 FALSE.

更新日志

版本	说明
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.

User Contributed Notes

andrew at rollason dot com 27-Oct-2017 06:59


It's worth noting that -- unlike many of the image functions -- imagescale returns a new image resource and leaves the existing image resource untouched.   



If you don't need the original image after generating a scaled version, remember to imagedestroy() it.