Seemingly, you can't omit the width the same way you do with the height. If you write -1 for the width and specify a number for the height it will return false
imagescale
(PHP 5 >= 5.5.0, PHP 7, PHP 8)
imagescale — Scale an image using the given new width and height
说明
imagescale(
GdImage
int
int
int
): GdImage|false
GdImage
$image,int
$width,int
$height = -1,int
$mode = IMG_BILINEAR_FIXED): GdImage|false
imagescale() scales an image using the given interpolation algorithm.
注意:
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 GdImage 对象。
-
width -
The width to scale the image to.
-
height -
The height to scale the image to. If omitted or negative, the aspect ratio will be preserved.
-
mode -
One of
IMG_NEAREST_NEIGHBOUR,IMG_BILINEAR_FIXED,IMG_BICUBIC,IMG_BICUBIC_FIXEDor anything else (will use two pass).注意:
IMG_WEIGHTED4is not yet supported.
返回值
Return the scaled image object on success 或者在失败时返回 false.
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | On success, this function returns a GDImage instance now; previously, a resource was returned. |
| 8.0.0 |
image 现在需要 GdImage 实例；之前需要有效的 gd resource。
|
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
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