jxl 0.4.0

High performance Rust implementation of a JPEG XL decoder
Documentation 
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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

use crate::api::JxlCms;

pub enum JxlProgressiveMode {
    /// Renders all pixels in every call to Process.
    Eager,
    /// Renders pixels once passes are completed.
    Pass,
    /// Renders pixels only once the final frame is ready.
    FullFrame,
}

#[non_exhaustive]
pub struct JxlDecoderOptions {
    pub adjust_orientation: bool,
    pub render_spot_colors: bool,
    pub coalescing: bool,
    pub desired_intensity_target: Option<f32>,
    pub skip_preview: bool,
    pub progressive_mode: JxlProgressiveMode,
    pub cms: Option<Box<dyn JxlCms>>,
    /// Fail decoding images with more than this number of pixels, or with frames with
    /// more than this number of pixels. The limit counts the product of pixels and
    /// channels, so for example an image with 1 extra channel of size 1024x1024 has 4
    /// million pixels.
    pub pixel_limit: Option<usize>,
    /// Use high precision mode for decoding.
    /// When false (default), uses lower precision settings that match libjxl's default.
    /// When true, uses higher precision at the cost of performance.
    ///
    /// This affects multiple decoder decisions including spline rendering precision
    /// and potentially intermediate buffer storage (e.g., using f32 vs f16).
    pub high_precision: bool,
    /// If true, multiply RGB by alpha before writing to output buffer.
    /// This produces premultiplied alpha output, which is useful for compositing.
    /// Default: false (output straight alpha)
    pub premultiply_output: bool,
    /// If true, only parse frame headers/TOC and skip section decoding.
    ///
    /// This is useful for collecting [`VisibleFrameInfo`](crate::api::VisibleFrameInfo)
    /// via the regular decoder API without producing pixels.
    pub scan_frames_only: bool,
}

impl Default for JxlDecoderOptions {
    fn default() -> Self {
        Self {
            adjust_orientation: true,
            render_spot_colors: true,
            coalescing: true,
            skip_preview: true,
            desired_intensity_target: None,
            progressive_mode: JxlProgressiveMode::Pass,
            cms: None,
            pixel_limit: None,
            high_precision: false,
            premultiply_output: false,
            scan_frames_only: false,
        }
    }
}