tree: Fix Transformation & Support Node-Anchors (#904)

* tree: Fix transformation and support named nodes

- Fixes transformations on the tree
- Support named elements in tree nodes

* tree: Fix transformation + node anchors

* changes: Update changelog

Author: johannes-wolf

CHANGES.md

@@ -1,9 +1,11 @@
 # 0.4.1
-- Added a `n-star` shape for drawing n-pointed stars (#886)
-- Added `breakable: false` to the `block` element of the canvas (#880)
-- A new tree layout algorithm, implemented by @MichaelGoodale in Rust, can handle differently sized tree nodes (#889)
-- **BREAKING** The `tree` callback for drawing nodes does not pass the parent nodes name anymor (new signature is `(node) => elements`) (#889)
-- **BREAKING** The `parent-position` argument of `tree` got removed (#889, #891)
+- Added a `n-star` shape for drawing n-pointed stars
+- Added `breakable: false` to the `block` element of the canvas
+- A new tree layout algorithm, implemented by @MichaelGoodale in Rust, can handle differently sized tree nodes
+- **BREAKING** The `tree` callback for drawing nodes does not pass the parent nodes name anymore (new signature is `(node) => elements`)
+- **BREAKING** The `parent-position` argument of `tree` got removed
+- Tree nodes now support anchors: custom anchors from the `draw-node` callback
+  are accessible.
 - `styles.resolve` now supports nested roots by passing an array (#914)
 
 # 0.4.0

src/lib/tree.typ

@@ -129,17 +129,15 @@
         depth: depth,
         children: children,
         content: content,
-        drawables: none,
       )
 
-      // Pre-Render the node
-      let (ctx: _, drawables, bounds) = process.many(ctx, draw.scope({
-        draw.set-origin((0, 0))
-        (draw-node)(node)
-      }))
-      node.drawables = drawables
-
+      // Measure the node
       if measure-content {
+        let (ctx: _, drawables: _, bounds) = process.many(ctx, {
+          draw.set-origin((0, 0))
+          (draw-node)(node)
+        })
+
         if bounds != none {
           (node.width, node.height, _) = aabb.size(bounds)
         }
@@ -190,21 +188,11 @@
       node.group-name = "g" + name
       node.element = {
         draw.anchor(node.name, node-position(node))
-        draw.group(
-          name: node.group-name,
-          {
-            draw.anchor("default", node-position(node))
-
-            (ctx => {
-              let (x, y) = node-position(node)
-              let translation = matrix.transform-translate(x, -y, 0)
-
-              return (
-                ctx: ctx,
-                drawables: drawable.apply-transform(
-                  translation, node.drawables),
-              )
-            },)
+        draw.group(name: node.group-name, ctx => {
+            let (x, y) = node-position(node)
+            draw.translate((x, y, 0))
+            draw.anchor("default", (0, 0))
+            draw-node(node)
           },
         )
       }

src/process.typ

@@ -35,6 +35,7 @@
   }
 
   let name = element.at("name", default: none)
+  element.name = name
   if name != none {
     assert.eq(type(name), str,
       message: "Element name must be a string")
@@ -64,6 +65,7 @@
     ctx: ctx,
     bounds: bounds,
     drawables: element.at("drawables", default: ()),
+    element: element,
   )
 }
 
@@ -74,6 +76,7 @@
 #let many(ctx, body) = {
   let drawables = ()
   let bounds = none
+  let elements = ()
 
   for el in body {
     let r = element(ctx, el)
@@ -85,6 +88,7 @@
       ctx = r.ctx
       drawables += r.drawables
     }
+    elements.push(r.element)
   }
-  return (ctx: ctx, bounds: bounds, drawables: drawables)
+  return (ctx: ctx, bounds: bounds, drawables: drawables, elements: elements)
 }