# imagescale

(PHP 5 >= 5.5.0, PHP 7)

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

### 说明

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

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

> Note:

> Unlike many of other image functions, imagescale() does not modify the passed `image`; instead, a new image is returned.

### 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.

### 参见

imagecopyresized() - 拷贝部分图像并调整大小 imagecopyresampled() - 重采样拷贝部分图像并调整大小