Function JxlDecoderSetUnpremultiplyAlpha 

pub unsafe extern "C-unwind" fn JxlDecoderSetUnpremultiplyAlpha(
    dec: *mut JxlDecoder,
    unpremul_alpha: JxlBool,
) -> JxlDecoderStatus

Enables or disables preserving of associated alpha channels. If unpremul_alpha is set to JxlBool::False then for associated alpha channel, the pixel data is returned with premultiplied colors. If it is set to JxlBool::True, the colors will be unpremultiplied based on the alpha channel. This function has no effect if the image does not have an associated alpha channel.

By default, this option is disabled, and the returned pixel data is “as is”.

This function must be called at the beginning, before decoding is performed.

Parameters

• dec: decoder object
• unpremul_alpha: JxlBool::True to enable, JxlBool::False to disable.

Returns

• JxlDecoderStatus::Success if no error, JxlDecoderStatus::Error otherwise.