From f8f6ea9729bf32ee3ca80e4d7bfe8b75ec80626f Mon Sep 17 00:00:00 2001
From: jacob <jacob@cagori.com>
Date: Wed, 5 Nov 2025 19:30:38 -0600
Subject: [PATCH] defer non-layout-axis fill size calculations

---
 src/ui/ui_common.c |  4 ----
 src/ui/ui_core.c   | 60 ++++++++++++++++++++++++++++++----------------
 src/ui/ui_core.h   |  3 ++-
 3 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/src/ui/ui_common.c b/src/ui/ui_common.c
index e524f7ab..a1cbd40d 100644
--- a/src/ui/ui_common.c
+++ b/src/ui/ui_common.c
@@ -31,10 +31,8 @@ UI_Box *UI_BuildLabelF_(char *fmt_cstr, ...)
 UI_Box *UI_BuildSpacer(UI_Size size)
 {
     UI_Box *box = 0;
-
     UI_Box *old_parent = UI_UseTop(Parent);
     Axis axis = old_parent->child_layout_axis;
-
     UI_PushEmptyStack();
     {
         UI_Push(Tint, 0);
@@ -50,13 +48,11 @@ UI_Box *UI_BuildSpacer(UI_Size size)
 UI_Box *UI_BuildDivider(UI_Size size)
 {
     UI_Box *box = 0;
-
     UI_Box *old_parent = UI_UseTop(Parent);
     u32 old_tint = UI_UseTop(Tint);
     f32 old_border = UI_UseTop(Border);
     u32 old_border_color = UI_UseTop(BorderColor);
     Axis axis = old_parent->child_layout_axis;
-
     UI_PushEmptyStack();
     {
         UI_Push(Parent, old_parent);
diff --git a/src/ui/ui_core.c b/src/ui/ui_core.c
index a367d35a..3163cc07 100644
--- a/src/ui/ui_core.c
+++ b/src/ui/ui_core.c
@@ -708,8 +708,6 @@ i64 UI_EndFrame(UI_Frame frame)
     render_viewport.pos = VEC2(0, 0);
     render_viewport.size = VEC2(draw_size.x, draw_size.y);
 
-    /* TODO: Ensure root is parent */
-
     //////////////////////////////
     //- Layout
 
@@ -812,12 +810,13 @@ i64 UI_EndFrame(UI_Frame frame)
         }
     }
 
-    /* Calculate upwards-dependent sizes */
+    /* Calculate upwards-dependent sizes along layout axis */
     for (u64 pre_index = 0; pre_index < boxes_count; ++pre_index)
     {
         UI_Box *box = boxes_pre[pre_index];
-        for (Axis axis = 0; axis < Axis_CountXY; ++axis)
+        if (box->parent)
         {
+            Axis axis = box->parent->child_layout_axis;
             UI_Size pref_size = box->pref_size[axis];
             if (pref_size.kind == UI_SizeKind_Fill)
             {
@@ -867,6 +866,21 @@ i64 UI_EndFrame(UI_Frame frame)
         }
     }
 
+    /* Calculate upwards-dependent sizes along non-layout axis */
+    for (u64 pre_index = 0; pre_index < boxes_count; ++pre_index)
+    {
+        UI_Box *box = boxes_pre[pre_index];
+        if (box->parent)
+        {
+            Axis axis = !box->parent->child_layout_axis;
+            UI_Size pref_size = box->pref_size[axis];
+            if (pref_size.kind == UI_SizeKind_Fill)
+            {
+                box->solved_dims[axis] = box->parent->solved_dims[axis] * pref_size.v;
+            }
+        }
+    }
+
     /* Solve violations */
     for (u64 pre_index = 0; pre_index < boxes_count; ++pre_index)
     {
@@ -927,23 +941,7 @@ i64 UI_EndFrame(UI_Frame frame)
                     }
                     size_accum = adjusted_size_accum;
                 }
-                /* Initialize layout cursor based on alignment */
-                if (axis == box->child_layout_axis)
-                {
-                    UI_AxisAlignment alignment = box->child_alignment[axis];
-                    switch(alignment)
-                    {
-                        default: break;
-                        case UI_AxisAlignment_Center:
-                        {
-                            box->layout_cursor = box_size / 2 - size_accum / 2;
-                        } break;
-                        case UI_AxisAlignment_End:
-                        {
-                            box->layout_cursor = box_size - size_accum;
-                        } break;
-                    }
-                }
+                box->final_children_size_accum[axis] = size_accum;
             }
             /* Solve floating violations */
             for (UI_Box *child = box->first; child; child = child->next)
@@ -968,6 +966,26 @@ i64 UI_EndFrame(UI_Frame frame)
         UI_Box *box = boxes_pre[pre_index];
         UI_Box *parent = box->parent;
 
+        /* Initialize layout cursor based on alignment */
+        {
+            Axis axis = box->child_layout_axis;
+            UI_AxisAlignment alignment = box->child_alignment[axis];
+            f32 box_size = box->solved_dims[axis];
+            f32 size_accum = box->final_children_size_accum[axis];
+            switch(alignment)
+            {
+                default: break;
+                case UI_AxisAlignment_Center:
+                {
+                    box->layout_cursor = box_size / 2 - size_accum / 2;
+                } break;
+                case UI_AxisAlignment_End:
+                {
+                    box->layout_cursor = box_size - size_accum;
+                } break;
+            }
+        }
+
         /* Position */
         {
             f32 *dims_arr = box->solved_dims;
diff --git a/src/ui/ui_core.h b/src/ui/ui_core.h
index 2ab0bcce..480ecbe3 100644
--- a/src/ui/ui_core.h
+++ b/src/ui/ui_core.h
@@ -244,8 +244,9 @@ Struct(UI_Box)
     //- Layout data
     F_Run glyph_run;
     F_Font *font;
-    f32 solved_dims[Axis_CountXY];
     f32 layout_cursor;
+    f32 solved_dims[Axis_CountXY];
+    f32 final_children_size_accum[Axis_CountXY];
 
     //- Post-layout data
     Vec2 p0;