cadcraft/crates/io/tests/dim_block_text.rs

//! The anonymous `*D` block written for a dimension (what other programs draw) holds its text at
//! the height it is drawn at: the dimension's overrides and DIMSCALE (0 = the drawing's) count
//! (issue #367).

use cadcraft_doc::{Common, DimKind, Dimension, Drawing, EntityKind, Space};
use cadcraft_geom::Vec3;

/// The group 40 (height) of the first MTEXT in the BLOCKS section.
fn block_mtext_height(dxf: &str) -> f64 {
    let lines: Vec<&str> = dxf.lines().map(str::trim).collect();
    let blocks = lines.windows(2).position(|w| w == ["2", "BLOCKS"]).unwrap();
    let mtext = blocks + lines[blocks..].windows(2).position(|w| w == ["0", "MTEXT"]).unwrap();
    let h = mtext + lines[mtext..].chunks(2).position(|w| w[0] == "40").unwrap() * 2;
    lines[h + 1].parse().unwrap()
}

fn height_written(style_scale: f64, overrides: serde_json::Value) -> f64 {
    let mut d = Drawing::new_imperial();
    d.dim_styles.iter_mut().for_each(|s| s.scale = style_scale);
    let dm = Dimension {
        kind: DimKind::Linear { rotation: 0.0 },
        defpt: Vec3::new(15.0, 5.0, 0.0),
        text_mid: Vec3::ZERO,
        p13: Vec3::ZERO,
        p14: Vec3::new(30.0, 0.0, 0.0),
        p15: Vec3::ZERO,
        p16: Vec3::ZERO,
        text: String::new(),
        style: "Standard".into(),
        measurement: 0.0,
        text_rotation: 0.0,
        user_text_pos: false,
        block: None,
        overrides: overrides.as_object().cloned().unwrap_or_default(),
        assoc: Vec::new(),
        marks: Default::default(),
    };
    d.add(&Space::Model, Common::default(), EntityKind::Dimension(dm)).unwrap();
    block_mtext_height(&cadcraft_io::write_dxf(&d))
}

#[test]
fn dimension_block_text_has_the_drawn_height() {
    let near = |a: f64, b: f64| (a - b).abs() < 1e-9;
    let plain = height_written(1.0, serde_json::json!({}));
    assert!(near(plain, 0.18), "{plain}");
    let scaled = height_written(1.0, serde_json::json!({"scale": 10.0}));
    assert!(near(scaled, 1.8), "a DIMSCALE override scales the block text: {scaled}");
    let txt = height_written(1.0, serde_json::json!({"DIMTXT": 0.5}));
    assert!(near(txt, 0.5), "a DIMTXT override sets the block text height: {txt}");
    let zero = height_written(0.0, serde_json::json!({}));
    assert!(near(zero, 0.18), "DIMSCALE 0 in model space is scale 1, not ~0: {zero}");
}