opacity for background color

[gb6881]

Hi,

we want to extend an image using "extend", the target image at the end should be supporting transparency/opacity.

• we want to extend the image using a specified background color (in case it's exported as an jpeg)
• for images exported in a format support transparency the background should also be transparent.

i tried with:

[
    {
        "operation": "resize",
        "params": {
            "extend": "background",
            "background": "255,255,255,0",
            "width": 1250,
            "stripmeta": false,
            "type": "webp",
            "nocrop": true,
            "height": 703
        }
    }
]

Source: Result: white-border.webp.gz

is there a way to make that border transparent?

Thanks, Georg