katana-document-viewer 0.1.4

KatanA document viewer artifact, render evaluation, and export foundation.
Documentation 
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use resvg::usvg;

use super::{RasterTarget, rasterizer_options};

fn parse_tree(svg: &str) -> Result<usvg::Tree, usvg::Error> {
    usvg::Tree::from_str(svg, &rasterizer_options())
}

#[test]
fn raster_target_preserves_size_when_max_width_is_bigger() -> Result<(), Box<dyn std::error::Error>>
{
    let tree = parse_tree(
        r#"<svg xmlns='http://www.w3.org/2000/svg' width='20' height='10'><rect width='20' height='10'/></svg>"#,
    )?;

    let target = RasterTarget::new(tree.size(), 40);

    assert_eq!(target.width(), 20);
    assert_eq!(target.height(), 10);
    Ok(())
}

#[test]
fn raster_target_down_scales_to_max_width() -> Result<(), Box<dyn std::error::Error>> {
    let tree = parse_tree(
        r#"<svg xmlns='http://www.w3.org/2000/svg' width='200' height='80'><rect width='200' height='80'/></svg>"#,
    )?;

    let target = RasterTarget::new(tree.size(), 50);

    assert_eq!(target.width(), 50);
    assert_eq!(target.height(), 20);
    Ok(())
}

#[test]
fn raster_target_clamps_at_maximum_edge() -> Result<(), Box<dyn std::error::Error>> {
    let tree = parse_tree(
        r#"<svg xmlns='http://www.w3.org/2000/svg' width='10000' height='2000'><rect width='10000' height='2000'/></svg>"#,
    )?;

    let target = RasterTarget::new(tree.size(), 12000);

    assert_eq!(target.width(), 8192);
    assert_eq!(target.height(), 1639);
    Ok(())
}

#[test]
fn raster_target_render_is_not_empty_canvas() -> Result<(), Box<dyn std::error::Error>> {
    let tree = parse_tree(
        r#"<svg xmlns='http://www.w3.org/2000/svg' width='2' height='3'><rect x='0' y='0' width='2' height='3' fill='black'/></svg>"#,
    )?;

    let target = RasterTarget::new(tree.size(), 2);
    let pixmap = target
        .render(&tree)
        .ok_or_else(|| std::io::Error::other("render returns output"))?;

    assert_eq!(pixmap.width(), 2);
    assert_eq!(pixmap.height(), 3);
    Ok(())
}

#[test]
fn raster_target_minimum_size_is_one_pixel() -> Result<(), Box<dyn std::error::Error>> {
    let tree = parse_tree(
        r#"<svg xmlns='http://www.w3.org/2000/svg' width='0.001' height='0.001'><rect/></svg>"#,
    )?;

    let target = RasterTarget::new(tree.size(), 100);

    assert_eq!(target.width(), 1);
    assert_eq!(target.height(), 1);
    Ok(())
}