rustmotion 0.6.1

A CLI tool that renders motion design videos from JSON scenarios. No browser, no Node.js — just a single Rust binary.
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//! Regression test — audit round 4, lot LAYOUT, constat 1.
//!
//! `vw`/`vh` (and `%`, `em`, `rem`) used to resolve against a hardcoded
//! 1920×1080 viewport and a hardcoded 16px font-size, no matter what
//! resolution the video was actually configured at. The culprit was
//! `ConversionContext::default()` being passed to `run_layout` in
//! `crates/rustmotion/src/engine/render/scene.rs`, instead of a context
//! built from the real `VideoConfig::{width,height}`.
//!
//! Vertical video (1080×1920, a common format for this project) is the
//! sharpest reproduction: `width: "50vw"` should be 540px (50% of the real
//! 1080px-wide viewport), not 960px (50% of the hardcoded 1920). Likewise
//! `height: "50vh"` should be 960px (50% of 1920), not 540px (50% of the
//! hardcoded 1080) — the bug doesn't just miscalculate, it silently swaps
//! which axis gets which fraction.

use rustmotion::engine::render::render_scene_hits;
use rustmotion::schema::{Scene, VideoConfig};

fn vertical_config() -> VideoConfig {
    serde_json::from_value(serde_json::json!({
        "width": 1080,
        "height": 1920,
        "fps": 30
    }))
    .expect("video config is schema-valid")
}

fn scene_with_vw_vh_shape() -> Scene {
    serde_json::from_value(serde_json::json!({
        "duration": 1.0,
        "children": [
            {
                "type": "shape",
                "shape": "rect",
                "style": { "width": "50vw", "height": "50vh" }
            }
        ]
    }))
    .expect("scene is schema-valid")
}

#[test]
fn vw_and_vh_resolve_against_the_real_video_viewport() {
    let config = vertical_config();
    let scene = scene_with_vw_vh_shape();

    let hits = render_scene_hits(&config, &scene, 0);
    let shape_hit = hits
        .iter()
        .find(|h| h.kind == "shape")
        .expect("shape hit present in render_scene_hits output");

    // 50% of the real 1080px-wide / 1920px-tall viewport — not 50% of a
    // hardcoded 1920×1080 (which would swap the two: 960 / 540).
    assert!(
        (shape_hit.rect.w - 540.0).abs() < 1.0,
        "expected 50vw on a 1080px-wide viewport to resolve to ~540px, got {}",
        shape_hit.rect.w
    );
    assert!(
        (shape_hit.rect.h - 960.0).abs() < 1.0,
        "expected 50vh on a 1920px-tall viewport to resolve to ~960px, got {}",
        shape_hit.rect.h
    );
}