Function JxlEncoderSetFrameLossless 

pub unsafe extern "C-unwind" fn JxlEncoderSetFrameLossless(
    frame_settings: *mut JxlEncoderFrameSettings,
    lossless: JxlBool,
) -> JxlEncoderStatus

Enables lossless encoding.

This is not an option like the others on itself, but rather while enabled it overrides a set of existing options (such as distance, modular mode and color transform) that enables bit-for-bit lossless encoding.

When disabled, those options are not overridden, but since those options could still have been manually set to a combination that operates losslessly, using this function with lossless set to JxlBool::False does not guarantee lossy encoding, though the default set of options is lossy.

Parameters

• frame_settings: set of options and metadata for this frame. Also includes reference to the encoder object.
• lossless: whether to override options for lossless mode

Returns

• JxlEncoderStatus::Success if the operation was successful, JxlEncoderStatus::Error otherwise.