OneCAD-Draft/src/scene/preview.rs

// Auto-split from scene/mod.rs. Pure text-move; behaviour unchanged.
use super::*;

impl Scene {
    // ── Preview wire ──────────────────────────────────────────────────────

    pub fn set_preview_wires(&mut self, wires: Vec<WireModel>) {
        // Preview wires are an overlay appended to the cached base wire set in
        // `build_primitive`; they are NOT part of the tessellation cache. So a
        // preview update must NOT bump `geometry_epoch` — that would re-
        // tessellate the whole model on every rubber-band frame. The overlay
        // forces a GPU wire re-upload on its own (the `has_overlay` content-id
        // path), and iced redraws after the message that set the preview.
        self.preview_wires = wires;
    }

    pub fn set_preview_text(&mut self, verts: Vec<crate::scene::pipeline::text_gpu::TextVertex>) {
        // Overlay glyphs — same reasoning as `set_preview_wires`: no geometry
        // bump. Uploaded to a dedicated per-frame text buffer in `prepare`.
        self.preview_text = verts;
    }

    pub fn clear_preview_wire(&mut self) {
        // No geometry bump — see `set_preview_wires`. Dropping the overlay
        // flips the wire content id back to the base tessellation id, which
        // re-uploads the base wires (without the preview) on the next frame.
        self.preview_wires = vec![];
        self.preview_text = vec![];
        self.interim_wire = None;
        // Drop any point-picked window marquee (STRETCH) so it doesn't linger
        // after the command ends before the next mouse move. (#291)
        self.selection.borrow_mut().preview_box = None;
    }

    pub fn wire_models_for(&self, handles: &[acadrust::Handle]) -> Vec<WireModel> {
        handles
            .iter()
            .flat_map(|h| {
                match self.document.get_entity(*h) {
                    // Hatches carry no outline in the normal wire set, but an
                    // edit preview (move / copy / array / grip-drag) needs to
                    // show the shape following the cursor. Build a live boundary
                    // from the current HatchModel — `apply_grip` keeps it in
                    // step, so the preview tracks a dragged grip in real time.
                    Some(EntityType::Hatch(_)) => {
                        self.hatch_outline_wire(*h).into_iter().collect()
                    }
                    Some(e) => self.tessellate_one(e),
                    None => Vec::new(),
                }
            })
            .collect()
    }

    /// Split a MIRROR selection into plain ghost wires (reflected wholesale) and
    /// text ghosts paired with their bounding-box centre. Lets the preview match
    /// the commit for TEXT: MIRRTEXT on → true glyph mirror (full reflection, same
    /// as plain geometry); MIRRTEXT off → right-reading at the mirror-symmetric
    /// position (reflect the centre, translate) instead of hugging the axis.
    pub fn mirror_preview_parts(
        &self,
        handles: &[Handle],
    ) -> (Vec<WireModel>, Vec<(WireModel, glam::DVec3)>) {
        let mut plain: Vec<WireModel> = Vec::new();
        let mut texts: Vec<(WireModel, glam::DVec3)> = Vec::new();
        for h in handles {
            let Some(e) = self.document.get_entity(*h) else {
                continue;
            };
            if matches!(e, EntityType::Text(_)) {
                let wires = self.tessellate_one(e);
                let mut lo = [f64::INFINITY; 2];
                let mut hi = [f64::NEG_INFINITY; 2];
                for w in &wires {
                    for (i, p) in w.points.iter().enumerate() {
                        if !p[0].is_finite() || !p[1].is_finite() {
                            continue;
                        }
                        // Reconstruct f64 world from the double-single pair (the
                        // low residual may be absent on some wires).
                        let l = w.points_low.get(i).copied().unwrap_or([0.0; 3]);
                        let (x, y) = (p[0] as f64 + l[0] as f64, p[1] as f64 + l[1] as f64);
                        lo[0] = lo[0].min(x);
                        lo[1] = lo[1].min(y);
                        hi[0] = hi[0].max(x);
                        hi[1] = hi[1].max(y);
                    }
                }
                let center = if lo[0] <= hi[0] {
                    glam::DVec3::new((lo[0] + hi[0]) * 0.5, (lo[1] + hi[1]) * 0.5, 0.0)
                } else {
                    glam::DVec3::ZERO
                };
                for w in wires {
                    texts.push((w, center));
                }
            } else {
                plain.extend(self.tessellate_one(e));
            }
        }
        (plain, texts)
    }

    /// Boundary outline wire for a hatch, reconstructed from its cached
    /// `HatchModel` (offsets from `world_origin`). Used only for edit previews —
    /// the normal render shows the fill, not this outline.
    fn hatch_outline_wire(&self, handle: Handle) -> Option<WireModel> {
        let m = self.hatches.get(&handle)?;
        let (wx, wy) = (m.world_origin[0], m.world_origin[1]);
        let pts: Vec<[f64; 3]> = m
            .boundary
            .iter()
            .map(|&[x, y]| {
                if x.is_finite() && y.is_finite() {
                    [wx + x as f64, wy + y as f64, 0.0]
                } else {
                    [f64::NAN; 3]
                }
            })
            .collect();
        if pts.len() < 2 {
            return None;
        }
        Some(WireModel::solid_f64(
            handle.value().to_string(),
            pts,
            m.color,
            false,
        ))
    }

    /// Build wire models for an arbitrary slice of entities (e.g. clipboard contents).
    /// Entities need not be in the document — they are tessellated directly.
    pub fn wires_for_entities(&self, entities: &[acadrust::EntityType]) -> Vec<WireModel> {
        entities
            .iter()
            .flat_map(|e| self.tessellate_one(e))
            .collect()
    }

    pub fn set_interim_wire(&mut self, w: WireModel) {
        // Overlay wire — same reasoning as `set_preview_wires`: no geometry
        // bump, so the model isn't re-tessellated on every interim update.
        self.interim_wire = Some(w);
    }
}