From a5af6b5af47b99e70a9d990f4783ca56175b71c5 Mon Sep 17 00:00:00 2001
From: Evan Reichard <evan@reichard.io>
Date: Mon, 3 Aug 2026 18:28:26 -0400
Subject: [PATCH] fix(node): only round a box that has a border

A filled box without one is a plain rectangle: rounding it leaves the
surface showing at the corners, which reads as a seam nobody asked for.
---
 native/src/node/painter.h    | 9 ++++++---
 native/test/runtime_test.cpp | 5 ++++-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/native/src/node/painter.h b/native/src/node/painter.h
index f519ef3..f76e757 100644
--- a/native/src/node/painter.h
+++ b/native/src/node/painter.h
@@ -78,13 +78,16 @@ class Painter {
     const bool hasFill = own && (own->set & S_FILL);
     if (!hasFill && !hasBorder) return;
 
-    const int32_t radius = tree.inherited(id, S_RADIUS).radius;
-    if (hasFill && radius == 0 && !hasBorder) {
+    // Only a bordered box rounds its corners. Filling a square first would leave corners
+    // outside the border, and rounding an unbordered fill puts a seam where a plain panel
+    // background was expected.
+    if (!hasBorder) {
       gui.fillRect(n.x, n.y, n.w, n.h, own->fill);
       return;
     }
     const int32_t fill = hasFill ? own->fill : tree.inherited(id, S_BG).bg;
-    gui.roundRect(n.x, n.y, n.w, n.h, radius, surfaceOf(id), &fill, &fill, hasBorder ? &own->border : nullptr);
+    gui.roundRect(n.x, n.y, n.w, n.h, tree.inherited(id, S_RADIUS).radius, surfaceOf(id), &fill, &fill,
+                  &own->border);
   }
 
   void paintButton(uint16_t id) {
diff --git a/native/test/runtime_test.cpp b/native/test/runtime_test.cpp
index 3246a34..9a70b7e 100644
--- a/native/test/runtime_test.cpp
+++ b/native/test/runtime_test.cpp
@@ -145,7 +145,8 @@ int main() {
       "local root = node.create(nil, {type = 'box', w = 'fill', h = 'fill', pad = 4, gap = 2})\n"
       "local label = node.create(root, {type = 'text', label = 'Hello'})\n"
       "local button = node.create(root, {type = 'button', h = 40, interactive = true})\n"
-      "node.setStyle(root, {background = 0xFFFFFF, fill = 0xFFFFFF, color = 0, face = 0xEEEEEE, focusColor = 0xFF0000})\n"
+      "node.setStyle(root, {background = 0xFFFFFF, fill = 0xFFFFFF, color = 0, face = 0xEEEEEE,\n"
+      "  border = 0x333333, focusColor = 0xFF0000})\n"
       "assert(node.layout(root, 0, 0, 320, 240))\n"
       "local x, y, w, h = node.getRect(label)\n"
       "assert(x == 4 and y == 4 and w == 312 and h == 16)\n"
@@ -161,6 +162,8 @@ int main() {
       "node.draw(root)\n"
       "node.dropScratch()");
   assert(bench.gui.trace.find("drawText(Hello);") != std::string::npos);
+  // The bordered box rounds its corners; the button fills without one.
+  assert(bench.gui.trace.find("roundRect(fill,border);") != std::string::npos);
   assert(bench.gui.trace.find("roundRect(fill,-);") != std::string::npos);
   expectError(state, "node.create(nil, {type = 'nope'})");