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
(PHP 5 >= 5.5.0, PHP 7, PHP 8)
imagescale — Scale an image using the given new width and height
$image,$width,$height = -1,$mode = IMG_BILINEAR_FIXEDimagescale() scales an image using the given interpolation algorithm.
Nota:
Unlike many of other image functions, imagescale() does not modify the passed
image; instead, a new image is returned.
imageUna risorsa immagine, restituita da una delle funzioni di creazione immagine, come imagecreatetruecolor().
widthThe width to scale the image to.
heightThe 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_FIXED or anything else (will use two
pass).
Nota:
IMG_WEIGHTED4is not yet supported.
Return the scaled image object on success o false in caso di fallimento.
Throws a ValueError if width
or height would cause over-/underflow.
Throws a ValueError if mode is invalid.
| Versione | Descrizione |
|---|---|
| 8.4.0 |
Now throws a ValueError if width
or height would cause over-/underflow.
|
| 8.4.0 |
Now throws a ValueError if mode is invalid.
|
| 8.0.0 | On success, this function returns a GDImage instance now; previously, a resource was returned. |
| 8.0.0 |
image expects a GdImage
instance now; previously, a valid gd resource was expected.
|
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 falseTo resize height without specifying a width you can rotate the image by 90 degrees, resize, then rotate by 270 degrees.
$outputImage = imagerotate($image, 90, 0);
$outputImage = imagescale($outputImage, $minSize);
$outputImage = imagerotate($outputImage, 270, 0);