minimal.rs

extern crate ghostscript;
use ghostscript as gs;
use gs::builder::{BuilderResult, GhostscriptBuilder};

fn main() {
    let mut builder = GhostscriptBuilder::new();

    builder.with_init_params(&[
        "-sDEVICE=pnggray",
        "-dNOPAUSE",
        "-dSAFER",
        "-sOutputFile=output.png",
        "-r100",
        "-dTextAlphaBits=4",
        "-dGraphicsAlphaBits=4",
        "--",
        "../input.pdf",
    ]);

    // If we used build() instead of build_simple() we could have passed any data
    // to associate with the new Ghostscript interpreter instance.
    // Such user data can also implement some useful Ghostscript callback traits.
    match builder.build_simple() {
        BuilderResult::Running(instance) => {
            // This is where we could get a running instance for further interpreter work.
            // But our init params above should have made the interpreter immediately quit
            // after rendering the file.
            eprintln!("Unexpected ghostscript instance: {:?}", instance);
            // Our user data can be extracted back, destroying the interpreter instance.
            eprintln!("I'm just a NoCallback: {:?}", instance.into_inner());
            unreachable!("The instance should have quit immediately after initialization.");
        },
        BuilderResult::Quit(user_data) => {
            // Interpreter ran and quit. Execution successfully completed.
            // Our user data is returned back. But we used build_simple() instead of build().
            println!("I'm just a NoCallback: {:?}", user_data);
        },
        BuilderResult::Failed(e) => {
            // Interpreter failed to build or run. The user_data is returned to us still.
            eprintln!("I'm just a NoCallback: {:?}", e.user_data);
            // As well as details about which part of the build process failed.
            panic!("Error building instance: {:?}", e.kind_and_code());
        },
    }

    // The builder can be reused to keep building new instances.
    // All the settings and parameters are preserved.
    // The following repeats the same rendering as above, but the has_quit() shorthand is used
    // to convert BuilderResult into Result in a similar way to the above match.
    builder
        .build_simple()
        .has_quit()
        .expect("Interpreter failed to start or kept running");
}