solidcraft-upstream/crates/engine/src/cmd/sketch_canvas.rs

//! Canvases (reference images on planes) and decals (images on planar faces).

use serde_json::{Value, json};
use solvecraft_doc::canvas::{Canvas, MAX_CANVAS_BYTES, base64_decode, base64_encode, image_info};
use solvecraft_geom::Vec2;

use super::CommandSpec;
use crate::params::{bad, bool_, num, str_, vec2};
use crate::{EngineError, Result, Session};

pub static COMMANDS: &[CommandSpec] = &[
    CommandSpec::new("canvas.insert", "Canvas", add_canvas)
        .at("SKETCH", "INSERT")
        .icon("canvas")
        .params("path | data (base64 PNG or JPEG); plane?: XY|XZ|YZ|{face: [x,y,z]}|… (default XY); center?: [x,y] on the plane, or at?: [x,y,z]; width?: mm (default 100); angle?: deg; opacity?: 0…1 (default 0.5); flip?; name?"),
    CommandSpec::new("canvas.decal", "Decal", add_decal)
        .at("SKETCH", "INSERT")
        .icon("decal")
        .params("path | data; face: [x,y,z] on a planar face (the image is centred there); width?: mm; angle?: deg; opacity?: (default 1)"),
    CommandSpec::new("canvas.edit", "Edit Canvas", edit_canvas).at("SKETCH", "INSERT").icon("canvas").params("canvas: id or name; center?, width?, angle?: deg, opacity?, flip?, visible?, name?"),
    CommandSpec::new("canvas.calibrate", "Calibrate Canvas", calibrate)
        .params("canvas: id or name; a, b: two points on the canvas plane [x,y]; distance: their true distance (mm): scales the image about a"),
    CommandSpec::new("canvas.delete", "Delete Canvas", delete_canvas).params("canvas: id or name"),
];

fn image_bytes(p: &Value, cmd: &str) -> Result<Vec<u8>> {
    let b = if let Some(d) = str_(p, "data") {
        if d.len() > MAX_CANVAS_BYTES * 4 / 3 + 16 {
            return Err(bad(cmd, "the image is too large"));
        }
        base64_decode(d).ok_or_else(|| bad(cmd, "`data` is not base64"))?
    } else {
        let path = str_(p, "path").filter(|x| !x.trim().is_empty() && x.len() < 4096).ok_or_else(|| bad(cmd, "give `path` or `data`"))?;
        let meta = solvecraft_io::vfs::len(path).map_err(|e| EngineError::Other(format!("{path}: {e}")))?;
        if meta as usize > MAX_CANVAS_BYTES {
            return Err(bad(cmd, "the image is too large"));
        }
        solvecraft_io::vfs::read(path).map_err(|e| EngineError::Other(format!("{path}: {e}")))?
    };
    if b.len() > MAX_CANVAS_BYTES {
        return Err(bad(cmd, "the image is too large"));
    }
    Ok(b)
}

fn make(s: &mut Session, p: &Value, cmd: &str, decal: bool) -> Result<Value> {
    let bytes = image_bytes(p, cmd)?;
    let (format, pixels) = image_info(&bytes).ok_or_else(|| bad(cmd, "only PNG and JPEG images can be inserted"))?;
    let plane = super::sketch::plane_ref(s, p, cmd)?;
    let (vals, _) = s.doc.param_values();
    let pl = s.doc.resolve_plane(&vals, &plane, 0)?;
    // A decal sits where the face was picked.
    let at = p.get("at").or_else(|| p.get("plane").and_then(|v| v.get("face"))).and_then(crate::params::vec3).map(|q| pl.to_local(q));
    let center = p.get("center").and_then(vec2).or(at).unwrap_or(Vec2::ZERO);
    let width = num(p, "width").unwrap_or(100.0);
    if !(width > 1e-6 && width < 1e7) {
        return Err(bad(cmd, "`width` must be positive"));
    }
    let opacity = num(p, "opacity").unwrap_or(if decal { 1.0 } else { 0.5 }).clamp(0.0, 1.0);
    let doc = s.doc_mut();
    let id = doc.canvases.iter().map(|c| c.id).max().unwrap_or(0) + 1;
    let base = if decal { "Decal" } else { "Canvas" };
    let name = str_(p, "name").map(str::to_string).unwrap_or_else(|| format!("{base}{id}"));
    doc.canvases.push(Canvas {
        id,
        name: name.clone(),
        format: format.into(),
        data: base64_encode(&bytes),
        pixels,
        plane,
        center,
        width,
        angle: num(p, "angle").unwrap_or(0.0).to_radians(),
        opacity,
        flip: bool_(p, "flip").unwrap_or(false),
        visible: true,
    });
    Ok(json!({"canvas": id, "name": name, "pixels": pixels}))
}

fn add_canvas(s: &mut Session, p: &Value) -> Result<Value> {
    make(s, p, "canvas.insert", false)
}

fn add_decal(s: &mut Session, p: &Value) -> Result<Value> {
    let cmd = "canvas.decal";
    let face = p.get("face").cloned().ok_or_else(|| bad(cmd, "`face` must be a point [x,y,z] on a planar face"))?;
    let mut q = p.clone();
    if let Some(o) = q.as_object_mut() {
        o.insert("plane".into(), json!({"face": face}));
    }
    make(s, &q, cmd, true)
}

fn find(s: &Session, p: &Value, cmd: &str) -> Result<usize> {
    let key = match p.get("canvas") {
        Some(Value::Number(n)) => n.to_string(),
        Some(Value::String(x)) => x.clone(),
        _ => return Err(bad(cmd, "`canvas` must be an id or a name")),
    };
    s.doc.canvases.iter().position(|c| c.id.to_string() == key || c.name == key).ok_or_else(|| bad(cmd, format!("no canvas `{key}`")))
}

fn edit_canvas(s: &mut Session, p: &Value) -> Result<Value> {
    let cmd = "canvas.edit";
    let i = find(s, p, cmd)?;
    let width = num(p, "width");
    if width.is_some_and(|w| !(w > 1e-6 && w < 1e7)) {
        return Err(bad(cmd, "`width` must be positive"));
    }
    let c = s.doc_mut().canvases.get_mut(i).ok_or_else(|| bad(cmd, "canvas"))?;
    if let Some(v) = p.get("center").and_then(vec2) {
        c.center = v;
    }
    if let Some(w) = width {
        c.width = w;
    }
    if let Some(a) = num(p, "angle") {
        c.angle = a.to_radians();
    }
    if let Some(o) = num(p, "opacity") {
        c.opacity = o.clamp(0.0, 1.0);
    }
    if let Some(f) = bool_(p, "flip") {
        c.flip = f;
    }
    if let Some(v) = bool_(p, "visible") {
        c.visible = v;
    }
    if let Some(n) = str_(p, "name").filter(|n| !n.trim().is_empty()) {
        c.name = n.to_string();
    }
    Ok(json!({"canvas": c.id}))
}

fn calibrate(s: &mut Session, p: &Value) -> Result<Value> {
    let cmd = "canvas.calibrate";
    let i = find(s, p, cmd)?;
    let (a, b) = (p.get("a").and_then(vec2), p.get("b").and_then(vec2));
    let (Some(a), Some(b)) = (a, b) else { return Err(bad(cmd, "`a` and `b` must be points [x,y]")) };
    let d = num(p, "distance").filter(|d| *d > 1e-9).ok_or_else(|| bad(cmd, "`distance` must be positive"))?;
    let now = a.dist(b);
    if now < 1e-9 {
        return Err(bad(cmd, "the points must differ"));
    }
    let k = d / now;
    let c = s.doc_mut().canvases.get_mut(i).ok_or_else(|| bad(cmd, "canvas"))?;
    c.width *= k;
    c.center = a + (c.center - a) * k;
    Ok(json!({"canvas": c.id, "width": c.width}))
}

fn delete_canvas(s: &mut Session, p: &Value) -> Result<Value> {
    let i = find(s, p, "canvas.delete")?;
    let c = s.doc_mut().canvases.remove(i);
    Ok(json!({"deleted": c.id}))
}

#[cfg(test)]
mod tests {
    use serde_json::json;
    use solvecraft_doc::canvas::base64_encode;

    use crate::Session;

    fn png(w: u32, h: u32) -> String {
        let mut b = b"\x89PNG\r\n\x1a\n\0\0\0\rIHDR".to_vec();
        b.extend(w.to_be_bytes());
        b.extend(h.to_be_bytes());
        b.extend([8, 6, 0, 0, 0, 0, 0, 0, 0]);
        base64_encode(&b)
    }

    #[test]
    fn canvas_insert_edit_calibrate_save() {
        let mut s = Session::default();
        let r = s.execute("canvas.insert", &json!({"data": png(400, 200), "plane": "XZ", "width": 80})).unwrap();
        let id = r["canvas"].as_u64().unwrap();
        let c = s.doc.canvases[0].clone();
        assert_eq!(c.pixels, [400, 200]);
        assert!((c.height() - 40.0).abs() < 1e-12);
        // Two points 20 apart on the image are really 50 apart.
        s.execute("canvas.calibrate", &json!({"canvas": id, "a": [0, 0], "b": [20, 0], "distance": 50})).unwrap();
        assert!((s.doc.canvases[0].width - 200.0).abs() < 1e-9);
        s.execute("canvas.edit", &json!({"canvas": "Canvas1", "opacity": 0.8, "angle": 90})).unwrap();
        // Undo-able and saved with the design.
        let back = solvecraft_doc::Document::from_json(&s.doc.to_json()).unwrap();
        assert_eq!(back.canvases, s.doc.canvases);
        s.execute("canvas.delete", &json!({"canvas": id})).unwrap();
        assert!(s.doc.canvases.is_empty());
        s.execute("edit.undo", &json!({})).unwrap();
        assert_eq!(s.doc.canvases.len(), 1);
        assert!(s.execute("canvas.insert", &json!({"data": "bm9wZQ=="})).is_err());
        // A decal on the top face of a box.
        s.execute("solid.box", &json!({"length": 30, "width": 30, "height": 10})).unwrap();
        let r = s.execute("canvas.decal", &json!({"data": png(10, 10), "face": [15, 15, 10], "width": 20})).unwrap();
        assert!(r["canvas"].is_u64());
    }
}