Function JxlEncoderAddImageFrame 

pub unsafe extern "C" fn JxlEncoderAddImageFrame(
    frame_settings: *const JxlEncoderFrameSettings,
    pixel_format: *const JxlPixelFormat,
    buffer: *const c_void,
    size: usize,
) -> JxlEncoderStatus

Sets the buffer to read pixels from for the next image to encode. Must call @ref JxlEncoderSetBasicInfo before @ref JxlEncoderAddImageFrame.

Currently only some data types for pixel formats are supported:

• ::JXL_TYPE_UINT8, with range 0..255
• ::JXL_TYPE_UINT16, with range 0..65535
• ::JXL_TYPE_FLOAT16, with nominal range 0..1
• ::JXL_TYPE_FLOAT, with nominal range 0..1

Note: the sample data type in pixel_format is allowed to be different from what is described in the @ref JxlBasicInfo. The type in pixel_format, together with an optional @ref JxlBitDepth parameter set by @ref JxlEncoderSetFrameBitDepth describes the format of the uncompressed pixel buffer. The bits_per_sample and exponent_bits_per_sample in the @ref JxlBasicInfo describes what will actually be encoded in the JPEG XL codestream. For example, to encode a 12-bit image, you would set bits_per_sample to 12, while the input frame buffer can be in the following formats:

• if pixel format is in ::JXL_TYPE_UINT16 with default bit depth setting (i.e. ::JXL_BIT_DEPTH_FROM_PIXEL_FORMAT), input sample values are rescaled to 16-bit, i.e. multiplied by 65535/4095;
• if pixel format is in ::JXL_TYPE_UINT16 with @ref JXL_BIT_DEPTH_FROM_CODESTREAM bit depth setting, input sample values are provided unscaled;
• if pixel format is in ::JXL_TYPE_FLOAT, input sample values are rescaled to 0..1, i.e. multiplied by 1.f/4095.f. While it is allowed, it is obviously not recommended to use a pixel_format with lower precision than what is specified in the @ref JxlBasicInfo.

We support interleaved channels as described by the @ref JxlPixelFormat “JxlPixelFormat”:

• single-channel data, e.g. grayscale
• single-channel + alpha
• trichromatic, e.g. RGB
• trichromatic + alpha

Extra channels not handled here need to be set by @ref JxlEncoderSetExtraChannelBuffer. If the image has alpha, and alpha is not passed here, it will implicitly be set to all-opaque (an alpha value of 1.0 everywhere).

The pixels are assumed to be encoded in the original profile that is set with @ref JxlEncoderSetColorEncoding or @ref JxlEncoderSetICCProfile. If none of these functions were used, the pixels are assumed to be nonlinear sRGB for integer data types (::JXL_TYPE_UINT8, ::JXL_TYPE_UINT16), and linear sRGB for floating point data types (::JXL_TYPE_FLOAT16, @ref JXL_TYPE_FLOAT).

Sample values in floating-point pixel formats are allowed to be outside the nominal range, e.g. to represent out-of-sRGB-gamut colors in the uses_original_profile=false case. They are however not allowed to be NaN or +-infinity.

If this is the last frame, @ref JxlEncoderCloseInput or @ref JxlEncoderCloseFrames must be called before the next @ref JxlEncoderProcessOutput call.

@param frame_settings set of options and metadata for this frame. Also includes reference to the encoder object. @param pixel_format format for pixels. Object owned by the caller and its contents are copied internally. @param buffer buffer type to input the pixel data from. Owned by the caller and its contents are copied internally. @param size size of buffer in bytes. This size should match what is implied by the frame dimensions and the pixel format. @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error