Struct JxlBasicInfo 

pub struct JxlBasicInfo {

    pub have_container: JxlBool,
    pub xsize: u32,
    pub ysize: u32,
    pub bits_per_sample: u32,
    pub exponent_bits_per_sample: u32,
    pub intensity_target: f32,
    pub min_nits: f32,
    pub relative_to_max_display: JxlBool,
    pub linear_below: f32,
    pub uses_original_profile: JxlBool,
    pub have_preview: JxlBool,
    pub have_animation: JxlBool,
    pub orientation: JxlOrientation,
    pub num_color_channels: u32,
    pub num_extra_channels: u32,
    pub alpha_bits: u32,
    pub alpha_exponent_bits: u32,
    pub alpha_premultiplied: JxlBool,
    pub preview: JxlPreviewHeader,
    pub animation: JxlAnimationHeader,
    pub intrinsic_xsize: u32,
    pub intrinsic_ysize: u32,
    /* private fields */
}

Basic image information. This information is available from the file signature and first part of the codestream header.

Fields

have_container: JxlBool

Whether the codestream is embedded in the container format. If true, metadata information and extensions may be available in addition to the codestream.

xsize: u32

Width of the image in pixels, before applying orientation.

ysize: u32

Height of the image in pixels, before applying orientation.

bits_per_sample: u32

Original image color channel bit depth.

exponent_bits_per_sample: u32

Original image color channel floating point exponent bits, or 0 if they are unsigned integer. For example, if the original data is half-precision (binary16) floating point, bits_per_sample is 16 and exponent_bits_per_sample is 5, and so on for other floating point precisions.

intensity_target: f32

Upper bound on the intensity level present in the image in nits. For unsigned integer pixel encodings, this is the brightness of the largest representable value. The image does not necessarily contain a pixel actually this bright. An encoder is allowed to set 255 for SDR images without computing a histogram. Leaving this set to its default of 0 lets libjxl choose a sensible default value based on the color encoding.

min_nits: f32

Lower bound on the intensity level present in the image. This may be loose, i.e. lower than the actual darkest pixel. When tone mapping, a decoder will map [min_nits, intensity_target] to the display range.

relative_to_max_display: JxlBool

See the description of Self::linear_below.

linear_below: f32

The tone mapping will leave unchanged (linear mapping) any pixels whose brightness is strictly below this. The interpretation depends on relative_to_max_display. If true, this is a ratio [0, 1] of the maximum display brightness [nits], otherwise an absolute brightness [nits].

uses_original_profile: JxlBool

Whether the data in the codestream is encoded in the original color profile that is attached to the codestream metadata header, or is encoded in an internally supported absolute color space (which the decoder can always convert to linear or non-linear sRGB or to XYB). If the original profile is used, the decoder outputs pixel data in the color space matching that profile, but doesn’t convert it to any other color space. If the original profile is not used, the decoder only outputs the data as sRGB (linear if outputting to floating point, nonlinear with standard sRGB transfer function if outputting to unsigned integers) but will not convert it to to the original color profile. The decoder also does not convert to the target display color profile. To convert the pixel data produced by the decoder to the original color profile, one of the JxlDecoderGetColor* functions needs to be called with JxlColorProfileTarget::Data to get the color profile of the decoder output, and then an external CMS can be used for conversion. Note that for lossy compression, this should be set to false for most use cases, and if needed, the image should be converted to the original color profile after decoding, as described above.

have_preview: JxlBool

Indicates a preview image exists near the beginning of the codestream. The preview itself or its dimensions are not included in the basic info.

have_animation: JxlBool

Indicates animation frames exist in the codestream. The animation information is not included in the basic info.

orientation: JxlOrientation

Image orientation, value 1-8 matching the values used by JEITA CP-3451C (Exif version 2.3).

num_color_channels: u32

Number of color channels encoded in the image, this is either 1 for grayscale data, or 3 for colored data. This count does not include the alpha channel or other extra channels. To check presence of an alpha channel, such as in the case of RGBA color, check alpha_bits != 0. If and only if this is 1, the JxlColorSpace in the JxlColorEncoding is JxlColorSpace::Gray.

num_extra_channels: u32

Number of additional image channels. This includes the main alpha channel, but can also include additional channels such as depth, additional alpha channels, spot colors, and so on. Information about the extra channels can be queried with JxlDecoderGetExtraChannelInfo. The main alpha channel, if it exists, also has its information available in the alpha_bits, alpha_exponent_bits and alpha_premultiplied fields in this JxlBasicInfo.

alpha_bits: u32

Bit depth of the encoded alpha channel, or 0 if there is no alpha channel. If present, matches the alpha_bits value of the JxlExtraChannelInfo associated with this alpha channel.

alpha_exponent_bits: u32

Alpha channel floating point exponent bits, or 0 if they are unsigned. If present, matches the alpha_bits value of the JxlExtraChannelInfo associated with this alpha channel. integer.

alpha_premultiplied: JxlBool

Whether the alpha channel is premultiplied. Only used if there is a main alpha channel. Matches the alpha_premultiplied value of the JxlExtraChannelInfo associated with this alpha channel.

preview: JxlPreviewHeader

Dimensions of encoded preview image, only used if have_preview is JxlBool::True.

animation: JxlAnimationHeader

Animation header with global animation properties for all frames, only used if have_animation is JxlBool::True.

intrinsic_xsize: u32

Intrinsic width of the image. The intrinsic size can be different from the actual size in pixels (as given by xsize and ysize) and it denotes the recommended dimensions for displaying the image, i.e. applications are advised to resample the decoded image to the intrinsic dimensions.

intrinsic_ysize: u32

Intrinsic height of the image. The intrinsic size can be different from the actual size in pixels (as given by xsize and ysize) and it denotes the recommended dimensions for displaying the image, i.e. applications are advised to resample the decoded image to the intrinsic dimensions.

Trait Implementations

impl Clone for JxlBasicInfo

fn clone(&self) -> JxlBasicInfo

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for JxlBasicInfo

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.