tawasuyu/brahman

Fase F: primer stub de pineal cerrado.

pineal-render:
- PlanRecorder — un Canvas que graba cada llamada como RenderCmd en un
  RenderPlan. Es el puente painter→backend-diferido y la infraestructura
  de testing (snapshot de planes).

pineal-export:
- svg::to_svg(plan, w, h) — RenderPlan → documento SVG completo.
  Cubre FillRect/StrokeRect/StrokeLine/StrokePolyline/DrawText +
  FillTriangleStrip (strip→polígonos con color promedio). XML-escape
  en texto. v1: clips ignorados (documentado).
- pdf queda como placeholder documentado.

Tests: 1 recorder + 4 svg (well-formed, primitivas, xml-escape,
triangle-strip→polygons). cargo check --workspace verde.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

diff --git a/crates/modules/pineal/export/src/lib.rs b/crates/modules/pineal/export/src/lib.rs
index 3ac171a..0ee9fea 100644
--- a/crates/modules/pineal/export/src/lib.rs
+++ b/crates/modules/pineal/export/src/lib.rs
@@ -1,23 +1,21 @@
-//! `pineal-export` — exporters.
+//! `pineal-export` — exporters de `RenderPlan`.
 //!
-//! Estrategia: implementar `pineal_render::Canvas` con un
-//! adapter que emite elementos SVG (o instrucciones PDF). El mismo
-//! painter que dibuja en pantalla escribe en el exporter — un sólo
-//! camino de código.
+//! Estrategia: el painter dibuja contra el trait `Canvas`; un
+//! `PlanRecorder` (en `pineal-render`) lo graba como `RenderPlan`; este
+//! crate consume el plan y emite el formato destino. Un solo camino de
+//! código para screen y export.
 //!
-//! Decimación contextual:
-//! ```text
-//! target = width_inches × dpi × vertices_per_pixel
-//! ```
-//! Print (300 dpi) saca ~3× más vértices que screen (96 dpi) del
-//! mismo source data (sección 3.10).
-//!
-//! - **`svg`** — exporter SVG.
-//! - **`pdf`** — placeholder; cuando se implemente, vía `printpdf`
-//!   sobre el mismo `RenderPlan` que el SVG.
+//! - [`svg`] — exporter SVG (implementado).
+//! - [`pdf`] — placeholder; cuando se implemente, vía `printpdf` sobre
+//!   el mismo `RenderPlan`, con decimación contextual por DPI
+//!   (`target = width_inches × dpi × vertices_per_pixel`).
 
 #![forbid(unsafe_code)]
-#![allow(dead_code)]
 
-pub mod svg {}
+pub mod svg;
+
+/// Exporter PDF — pendiente. Se implementará sobre `printpdf`
+/// consumiendo el mismo `RenderPlan` que `svg`.
 pub mod pdf {}
+
+pub use svg::to_svg;
diff --git a/crates/modules/pineal/export/src/svg.rs b/crates/modules/pineal/export/src/svg.rs
new file mode 100644
index 0000000..93f418b
--- /dev/null
+++ b/crates/modules/pineal/export/src/svg.rs
@@ -0,0 +1,223 @@
+//! Exporter SVG: un [`RenderPlan`] → documento SVG completo.
+//!
+//! El mismo painter que dibuja en pantalla (vía el trait `Canvas`) se
+//! graba con un `PlanRecorder` y el plan resultante se vuelca acá. Un
+//! solo camino de código para screen y export.
+//!
+//! v1: los comandos de clip (`PushClip`/`PopClip`) se ignoran — el
+//! recorte no es crítico para la mayoría de exports y SVG `clipPath`
+//! agrega complejidad de IDs. Se puede agregar después sin romper API.
+
+use pineal_render::{Color, RenderCmd, RenderPlan};
+use std::fmt::Write;
+
+/// Convierte un `RenderPlan` a un documento SVG de `width × height`.
+pub fn to_svg(plan: &RenderPlan, width: f32, height: f32) -> String {
+    let mut s = String::with_capacity(256 + plan.cmds.len() * 80);
+    let _ = write!(
+        s,
+        "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"{width}\" \
+         height=\"{height}\" viewBox=\"0 0 {width} {height}\">"
+    );
+    for cmd in &plan.cmds {
+        emit_cmd(&mut s, cmd);
+    }
+    s.push_str("</svg>");
+    s
+}
+
+fn emit_cmd(s: &mut String, cmd: &RenderCmd) {
+    match cmd {
+        // v1: clips ignorados (ver doc del módulo).
+        RenderCmd::PushClip(_) | RenderCmd::PopClip => {}
+
+        RenderCmd::FillRect { rect, color } => {
+            let (c, a) = svg_color(*color);
+            let _ = write!(
+                s,
+                "<rect x=\"{}\" y=\"{}\" width=\"{}\" height=\"{}\" \
+                 fill=\"{c}\" fill-opacity=\"{a}\"/>",
+                rect.x, rect.y, rect.w, rect.h
+            );
+        }
+
+        RenderCmd::StrokeRect { rect, stroke } => {
+            let (c, a) = svg_color(stroke.color);
+            let _ = write!(
+                s,
+                "<rect x=\"{}\" y=\"{}\" width=\"{}\" height=\"{}\" \
+                 fill=\"none\" stroke=\"{c}\" stroke-opacity=\"{a}\" \
+                 stroke-width=\"{}\"/>",
+                rect.x, rect.y, rect.w, rect.h, stroke.width
+            );
+        }
+
+        RenderCmd::StrokeLine { a: p0, b: p1, stroke } => {
+            let (c, alpha) = svg_color(stroke.color);
+            let _ = write!(
+                s,
+                "<line x1=\"{}\" y1=\"{}\" x2=\"{}\" y2=\"{}\" \
+                 stroke=\"{c}\" stroke-opacity=\"{alpha}\" stroke-width=\"{}\"/>",
+                p0.x, p0.y, p1.x, p1.y, stroke.width
+            );
+        }
+
+        RenderCmd::StrokePolyline { coords, stroke } => {
+            let (c, alpha) = svg_color(stroke.color);
+            s.push_str("<polyline points=\"");
+            emit_points(s, coords);
+            let _ = write!(
+                s,
+                "\" fill=\"none\" stroke=\"{c}\" stroke-opacity=\"{alpha}\" \
+                 stroke-width=\"{}\"/>",
+                stroke.width
+            );
+        }
+
+        RenderCmd::FillTriangleStrip { coords, colors } => {
+            emit_triangle_strip(s, coords, colors);
+        }
+
+        RenderCmd::DrawText { p, text, color, size_px } => {
+            let (c, a) = svg_color(*color);
+            let _ = write!(
+                s,
+                "<text x=\"{}\" y=\"{}\" fill=\"{c}\" fill-opacity=\"{a}\" \
+                 font-size=\"{size_px}\">{}</text>",
+                p.x, p.y, escape_xml(text)
+            );
+        }
+    }
+}
+
+/// Emite `x0,y0 x1,y1 …` para el atributo `points` de polyline/polygon.
+fn emit_points(s: &mut String, coords: &[f32]) {
+    for (i, pair) in coords.chunks_exact(2).enumerate() {
+        if i > 0 {
+            s.push(' ');
+        }
+        let _ = write!(s, "{},{}", pair[0], pair[1]);
+    }
+}
+
+/// Un triangle strip de N vértices = N-2 triángulos. Cada triángulo se
+/// emite como `<polygon>` con el color promedio de sus 3 vértices (SVG
+/// no tiene gradient por-vértice trivial).
+fn emit_triangle_strip(s: &mut String, coords: &[f32], colors: &[Color]) {
+    let n = coords.len() / 2;
+    if n < 3 {
+        return;
+    }
+    for t in 0..n - 2 {
+        let (i0, i1, i2) = (t, t + 1, t + 2);
+        let avg = avg_color(&[
+            colors.get(i0).copied(),
+            colors.get(i1).copied(),
+            colors.get(i2).copied(),
+        ]);
+        let (c, a) = svg_color(avg);
+        let _ = write!(
+            s,
+            "<polygon points=\"{},{} {},{} {},{}\" fill=\"{c}\" fill-opacity=\"{a}\"/>",
+            coords[i0 * 2], coords[i0 * 2 + 1],
+            coords[i1 * 2], coords[i1 * 2 + 1],
+            coords[i2 * 2], coords[i2 * 2 + 1],
+        );
+    }
+}
+
+fn avg_color(cs: &[Option<Color>]) -> Color {
+    let mut acc = Color::rgba(0.0, 0.0, 0.0, 0.0);
+    let mut n = 0.0;
+    for c in cs.iter().flatten() {
+        acc.r += c.r;
+        acc.g += c.g;
+        acc.b += c.b;
+        acc.a += c.a;
+        n += 1.0;
+    }
+    if n == 0.0 {
+        return Color::TRANSPARENT;
+    }
+    Color::rgba(acc.r / n, acc.g / n, acc.b / n, acc.a / n)
+}
+
+/// `Color` f32 → (`rgb(R,G,B)` con enteros 0-255, alpha 0-1).
+fn svg_color(c: Color) -> (String, f32) {
+    let to255 = |v: f32| (v.clamp(0.0, 1.0) * 255.0).round() as u8;
+    (
+        format!("rgb({},{},{})", to255(c.r), to255(c.g), to255(c.b)),
+        c.a.clamp(0.0, 1.0),
+    )
+}
+
+/// Escapa los 5 caracteres especiales de XML en contenido de texto.
+fn escape_xml(text: &str) -> String {
+    let mut out = String::with_capacity(text.len());
+    for ch in text.chars() {
+        match ch {
+            '&' => out.push_str("&amp;"),
+            '<' => out.push_str("&lt;"),
+            '>' => out.push_str("&gt;"),
+            '"' => out.push_str("&quot;"),
+            '\'' => out.push_str("&apos;"),
+            c => out.push(c),
+        }
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pineal_render::{Canvas, Point, Rect, StrokeStyle};
+
+    fn sample_plan() -> RenderPlan {
+        let mut rec = pineal_render::PlanRecorder::new();
+        rec.fill_rect(Rect::new(1.0, 2.0, 30.0, 40.0), Color::from_hex(0xff0000));
+        rec.stroke_line(
+            Point::new(0.0, 0.0),
+            Point::new(100.0, 50.0),
+            StrokeStyle::new(2.0, Color::BLACK),
+        );
+        rec.draw_text(Point::new(5.0, 10.0), "a<b&c", Color::WHITE, 12.0);
+        rec.into_plan()
+    }
+
+    #[test]
+    fn emits_well_formed_svg() {
+        let svg = to_svg(&sample_plan(), 200.0, 100.0);
+        assert!(svg.starts_with("<svg xmlns=\"http://www.w3.org/2000/svg\""));
+        assert!(svg.ends_with("</svg>"));
+        assert!(svg.contains("width=\"200\""));
+        assert!(svg.contains("viewBox=\"0 0 200 100\""));
+    }
+
+    #[test]
+    fn emits_each_primitive() {
+        let svg = to_svg(&sample_plan(), 200.0, 100.0);
+        assert!(svg.contains("<rect "));
+        assert!(svg.contains("fill=\"rgb(255,0,0)\""));
+        assert!(svg.contains("<line "));
+        assert!(svg.contains("<text "));
+    }
+
+    #[test]
+    fn escapes_xml_in_text() {
+        let svg = to_svg(&sample_plan(), 200.0, 100.0);
+        assert!(svg.contains("a&lt;b&amp;c"));
+        assert!(!svg.contains("a<b&c"));
+    }
+
+    #[test]
+    fn triangle_strip_becomes_polygons() {
+        let mut rec = pineal_render::PlanRecorder::new();
+        rec.fill_triangle_strip(
+            &[0.0, 0.0, 10.0, 0.0, 5.0, 10.0, 15.0, 10.0],
+            &[Color::WHITE, Color::WHITE, Color::WHITE, Color::WHITE],
+        );
+        let svg = to_svg(&rec.into_plan(), 20.0, 20.0);
+        // 4 vértices → 2 triángulos → 2 polígonos.
+        assert_eq!(svg.matches("<polygon").count(), 2);
+    }
+}
diff --git a/crates/modules/pineal/render/src/lib.rs b/crates/modules/pineal/render/src/lib.rs
index 281b446..7143c1d 100644
--- a/crates/modules/pineal/render/src/lib.rs
+++ b/crates/modules/pineal/render/src/lib.rs
@@ -23,6 +23,7 @@ pub mod color;
 pub mod geom;
 pub mod canvas;
 pub mod plan;
+pub mod recorder;
 
 #[cfg(feature = "gpui")]
 pub mod gpui_backend;
@@ -31,6 +32,7 @@ pub use color::Color;
 pub use geom::{Point, Rect};
 pub use canvas::{Canvas, StrokeStyle};
 pub use plan::{RenderCmd, RenderPlan};
+pub use recorder::PlanRecorder;
 
 #[cfg(feature = "gpui")]
 pub use gpui_backend::WindowCanvas;
diff --git a/crates/modules/pineal/render/src/recorder.rs b/crates/modules/pineal/render/src/recorder.rs
new file mode 100644
index 0000000..d36c0ff
--- /dev/null
+++ b/crates/modules/pineal/render/src/recorder.rs
@@ -0,0 +1,95 @@
+//! `PlanRecorder` — un [`Canvas`] que graba cada llamada como `RenderCmd`
+//! en un [`RenderPlan`], en vez de dibujar.
+//!
+//! Es el puente entre los painters (que hablan contra `Canvas`) y los
+//! backends diferidos: `pineal-export` consume el plan grabado y emite
+//! SVG; los tests de snapshot comparan planes.
+
+use crate::{Canvas, Color, Point, Rect, RenderCmd, RenderPlan, StrokeStyle};
+
+/// Canvas que materializa todo lo dibujado en un `RenderPlan`.
+#[derive(Debug, Default)]
+pub struct PlanRecorder {
+    plan: RenderPlan,
+}
+
+impl PlanRecorder {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Consume el recorder y devuelve el plan acumulado.
+    pub fn into_plan(self) -> RenderPlan {
+        self.plan
+    }
+
+    /// Acceso de sólo-lectura al plan en construcción.
+    pub fn plan(&self) -> &RenderPlan {
+        &self.plan
+    }
+}
+
+impl Canvas for PlanRecorder {
+    fn push_clip(&mut self, rect: Rect) {
+        self.plan.push(RenderCmd::PushClip(rect));
+    }
+
+    fn pop_clip(&mut self) {
+        self.plan.push(RenderCmd::PopClip);
+    }
+
+    fn fill_rect(&mut self, rect: Rect, color: Color) {
+        self.plan.push(RenderCmd::FillRect { rect, color });
+    }
+
+    fn stroke_rect(&mut self, rect: Rect, stroke: StrokeStyle) {
+        self.plan.push(RenderCmd::StrokeRect { rect, stroke });
+    }
+
+    fn stroke_line(&mut self, a: Point, b: Point, stroke: StrokeStyle) {
+        self.plan.push(RenderCmd::StrokeLine { a, b, stroke });
+    }
+
+    fn stroke_polyline(&mut self, coords: &[f32], stroke: StrokeStyle) {
+        self.plan.push(RenderCmd::StrokePolyline {
+            coords: coords.to_vec(),
+            stroke,
+        });
+    }
+
+    fn fill_triangle_strip(&mut self, coords: &[f32], colors: &[Color]) {
+        self.plan.push(RenderCmd::FillTriangleStrip {
+            coords: coords.to_vec(),
+            colors: colors.to_vec(),
+        });
+    }
+
+    fn draw_text(&mut self, p: Point, text: &str, color: Color, size_px: f32) {
+        self.plan.push(RenderCmd::DrawText {
+            p,
+            text: text.to_string(),
+            color,
+            size_px,
+        });
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn records_calls_in_order() {
+        let mut rec = PlanRecorder::new();
+        rec.fill_rect(Rect::new(0.0, 0.0, 10.0, 10.0), Color::WHITE);
+        rec.stroke_line(
+            Point::new(0.0, 0.0),
+            Point::new(10.0, 10.0),
+            StrokeStyle::new(1.0, Color::BLACK),
+        );
+        let plan = rec.into_plan();
+        assert_eq!(plan.cmds.len(), 2);
+        assert!(matches!(plan.cmds[0], RenderCmd::FillRect { .. }));
+        assert!(matches!(plan.cmds[1], RenderCmd::StrokeLine { .. }));
+    }
+}