From f6d820e51b2d20448368a93a88efc75f8e877f96 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Fri, 19 Jan 2024 17:56:49 +0100
Subject: [PATCH] WIP

---
 Cargo.lock                      |  2 +-
 crates/gpui/Cargo.toml          |  2 +-
 crates/gpui/src/elements/div.rs |  9 +++------
 crates/gpui/src/taffy.rs        |  7 ++++++-
 crates/gpui/src/window.rs       | 12 ++++++++++--
 5 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 010e7763e4..015f96033a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -7774,7 +7774,7 @@ dependencies = [
 [[package]]
 name = "taffy"
 version = "0.3.11"
-source = "git+https://github.com/DioxusLabs/taffy?rev=1876f72bee5e376023eaa518aa7b8a34c769bd1b#1876f72bee5e376023eaa518aa7b8a34c769bd1b"
+source = "git+https://github.com/DioxusLabs/taffy?rev=64f8aa0fb114d939ca0d53ddc44045a03fde548d#64f8aa0fb114d939ca0d53ddc44045a03fde548d"
 dependencies = [
  "arrayvec 0.7.4",
  "grid",
diff --git a/crates/gpui/Cargo.toml b/crates/gpui/Cargo.toml
index 70608ccb0c..4b5baf1ed2 100644
--- a/crates/gpui/Cargo.toml
+++ b/crates/gpui/Cargo.toml
@@ -46,7 +46,7 @@ serde_derive.workspace = true
 serde_json.workspace = true
 smallvec.workspace = true
 smol.workspace = true
-taffy = { git = "https://github.com/DioxusLabs/taffy", rev = "1876f72bee5e376023eaa518aa7b8a34c769bd1b" }
+taffy = { git = "https://github.com/DioxusLabs/taffy", rev = "64f8aa0fb114d939ca0d53ddc44045a03fde548d", features = ["content_size"] }
 thiserror.workspace = true
 time.workspace = true
 tiny-skia = "0.5"
diff --git a/crates/gpui/src/elements/div.rs b/crates/gpui/src/elements/div.rs
index aa912eadbe..3b3e35a9e5 100644
--- a/crates/gpui/src/elements/div.rs
+++ b/crates/gpui/src/elements/div.rs
@@ -802,6 +802,7 @@ impl Element for Div {
         (
             layout_id,
             DivState {
+                layout_id,
                 interactive_state,
                 child_layout_ids,
             },
@@ -839,12 +840,7 @@ impl Element for Div {
             }
             (child_max - child_min).into()
         } else {
-            for child_layout_id in &element_state.child_layout_ids {
-                let child_bounds = cx.layout_bounds(*child_layout_id);
-                child_min = child_min.min(&child_bounds.origin);
-                child_max = child_max.max(&child_bounds.lower_right());
-            }
-            (child_max - child_min).into()
+            cx.layout_scroll_size(element_state.layout_id)
         };
 
         self.interactivity.paint(
@@ -876,6 +872,7 @@ impl IntoElement for Div {
 }
 
 pub struct DivState {
+    layout_id: LayoutId,
     child_layout_ids: SmallVec<[LayoutId; 2]>,
     interactive_state: InteractiveElementState,
 }
diff --git a/crates/gpui/src/taffy.rs b/crates/gpui/src/taffy.rs
index 26d5a2e69e..b77e91056d 100644
--- a/crates/gpui/src/taffy.rs
+++ b/crates/gpui/src/taffy.rs
@@ -1,5 +1,5 @@
 use crate::{
-    AbsoluteLength, Bounds, DefiniteLength, Edges, Length, Pixels, Point, Size, Style,
+    size, AbsoluteLength, Bounds, DefiniteLength, Edges, Length, Pixels, Point, Size, Style,
     WindowContext,
 };
 use collections::{FxHashMap, FxHashSet};
@@ -227,6 +227,11 @@ impl TaffyLayoutEngine {
 
         bounds
     }
+
+    pub fn layout_scroll_size(&self, id: LayoutId) -> Size<Pixels> {
+        let layout = self.taffy.layout(id.into()).expect(EXPECT_MESSAGE);
+        size(layout.scroll_width().into(), layout.scroll_height().into())
+    }
 }
 
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
diff --git a/crates/gpui/src/window.rs b/crates/gpui/src/window.rs
index 4e7ba2001a..b7dcda548e 100644
--- a/crates/gpui/src/window.rs
+++ b/crates/gpui/src/window.rs
@@ -874,12 +874,20 @@ impl<'a> WindowContext<'a> {
             .layout_engine
             .as_mut()
             .unwrap()
-            .layout_bounds(layout_id)
-            .map(Into::into);
+            .layout_bounds(layout_id);
         bounds.origin += self.element_offset();
         bounds
     }
 
+    /// todo!()
+    pub fn layout_scroll_size(&self, layout_id: LayoutId) -> Size<Pixels> {
+        self.window
+            .layout_engine
+            .as_ref()
+            .unwrap()
+            .layout_scroll_size(layout_id)
+    }
+
     fn window_bounds_changed(&mut self) {
         self.window.scale_factor = self.window.platform_window.scale_factor();
         self.window.viewport_size = self.window.platform_window.content_size();