Module backend 

Backend Trait

Backend trait for implementing output format backends.

Overview

The Backend trait defines the interface that backends must implement to support different output formats (PDF, SVG, TXT, etc.).

Trait Definition

pub trait Backend: Send + Sync {
    fn id(&self) -> &'static str;
    fn supported_formats(&self) -> &'static [OutputFormat];
    fn glue_extension_types(&self) -> &'static [&'static str];
    fn allow_auto_glue(&self) -> bool;
    fn register_filters(&self, glue: &mut Glue);
    fn compile(
        &self,
        glue_content: &str,
        quill: &Quill,
        opts: &RenderOptions,
    ) -> Result<RenderResult, RenderError>;
}

Implementation Guide

Required Methods

id()

Return a unique backend identifier (e.g., “typst”, “latex”).

supported_formats()

Return a slice of OutputFormat variants this backend supports.

glue_extension_types()

Return the file extensions for glue files (e.g., &[“.typ”], &[“.tex”]). Return an empty array to disable custom glue files.

allow_auto_glue()

Return whether automatic JSON glue generation is allowed.

register_filters()

Register backend-specific filters with the glue environment.

fn register_filters(&self, glue: &mut Glue) {
    glue.register_filter("String", string_filter);
    glue.register_filter("Content", content_filter);
    glue.register_filter("Lines", lines_filter);
}

compile()

Compile glue content into final artifacts.

fn compile(
    &self,
    glue_content: &str,
    quill: &Quill,
    opts: &RenderOptions,
) -> Result<RenderResult, RenderError> {
    // 1. Create compilation environment
    // 2. Load assets from quill
    // 3. Compile glue content
    // 4. Handle errors and map to Diagnostics
    // 5. Return RenderResult with artifacts and output format
     
    let artifacts = vec![Artifact {
        bytes: compiled_pdf,
        output_format: format,
    }];
     
    Ok(RenderResult::new(artifacts, format))
}

Example Implementation

See quillmark-typst for a complete backend implementation example.

Thread Safety

The Backend trait requires Send + Sync to enable concurrent rendering. All backend implementations must be thread-safe.

Traits

Backend

Backend trait for rendering different output formats