feat: propagate selective corner rounding flags to GPU vertex generator

 src/backend/window_runner.rs |  6 +++---
 src/layout.rs                | 29 +++++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/backend/window_runner.rs b/src/backend/window_runner.rs
index 8599605..c199ded 100644
--- a/src/backend/window_runner.rs
+++ b/src/backend/window_runner.rs
@@ -818,7 +818,7 @@ pub trait Application: Sized + 'static {
     fn update(&mut self, msg: Self::Message, needs_rebuild: &mut bool, exit: &mut bool);
     fn tick(&mut self, dt: f32, needs_rebuild: &mut bool);
     fn view(&mut self, quads: &mut Vec<(f32, f32, f32, f32, [f32; 4])>, size: LogicalSize, scale: f64);
-    fn view_rounded_quads(&mut self, _quads: &mut Vec<(f32, f32, f32, f32, f32, [f32; 4])>, _size: LogicalSize, _scale: f64) {}
+    fn view_rounded_quads(&mut self, _quads: &mut Vec<(f32, f32, f32, f32, f32, [f32; 4], (bool, bool, bool, bool))>, _size: LogicalSize, _scale: f64) {}
     fn view_vectors(&mut self, _vectors: &mut Vec<(f32, f32, f32, f32, f32, [f32; 4], LineCap)>, _size: LogicalSize, _scale: f64) {}
     fn overlay_quads(&mut self, _quads: &mut Vec<(f32, f32, f32, f32, [f32; 4])>, _size: LogicalSize, _scale: f64) {}
     fn text_items(&self) -> &[TextItem];
@@ -1080,9 +1080,9 @@ impl<A: Application> EngineState<A> {
         for &(qx, qy, qw, qh, qc) in &quads {
             verts.extend(quad_vertices(qx, qy, qw, qh, logical_w, logical_h, qc));
         }
-        for &(qx, qy, qw, qh, qr, qc) in &rounded_quads {
+        for &(qx, qy, qw, qh, qr, qc, qcorners) in &rounded_quads {
             if qr > 0.1 {
-                push_rounded_rect_vertices_corners(qx, qy, qw, qh, qr, logical_w, logical_h, qc, [0.0, 0.0, 0.0], (true, true, true, true), None, &mut verts);
+                push_rounded_rect_vertices_corners(qx, qy, qw, qh, qr, logical_w, logical_h, qc, [0.0, 0.0, 0.0], qcorners, None, &mut verts);
             } else {
                 verts.extend(quad_vertices(qx, qy, qw, qh, logical_w, logical_h, qc));
             }
diff --git a/src/layout.rs b/src/layout.rs
index cd23954..9fad040 100644
--- a/src/layout.rs
+++ b/src/layout.rs
@@ -1171,6 +1171,9 @@ pub trait RenderTarget {
     fn rect_with_radius(&mut self, color: [f32; 4], x: f32, y: f32, w: f32, h: f32, _radius: f32) {
         self.rect(color, x, y, w, h);
     }
+    fn rect_with_radius_corners(&mut self, color: [f32; 4], x: f32, y: f32, w: f32, h: f32, radius: f32, _corners: (bool, bool, bool, bool)) {
+        self.rect_with_radius(color, x, y, w, h, radius);
+    }
     fn text(&mut self, content: &str, x: f32, y: f32, size: f32, color: [f32; 4]);
     fn text_with_font(&mut self, content: &str, x: f32, y: f32, size: f32, color: [f32; 4], _font: &str) {
         self.text(content, x, y, size, color);
@@ -1218,13 +1221,35 @@ impl RenderTarget for PopoverCollector {
 
 pub fn render_widget<T: Element + 'static>(pc: &mut dyn RenderTarget, w: &mut T, x: f32, y: f32, ww: f32, wh: f32, ctx: &mut UiContext) {
     w.layout(crate::widget::Point { x, y }, crate::widget::LayoutConstraints::new(ww, ww, wh, wh), ctx);
-    let r = if w.rounded_corners() != (false, false, false, false) {
+    let corners = w.rounded_corners();
+    let r = if corners != (false, false, false, false) {
         w.corner_radius()
     } else {
         0.0
     };
+    let (wx, mut wy, www, mut whh) = w.rect();
+    let top_room = crate::widget::label_offset(w);
+    wy += top_room;
+    whh -= top_room;
+
     for (qx, qy, qw, qh, qc) in w.all_quads(ctx) {
-        pc.rect_with_radius(qc, qx, qy, qw, qh, r);
+        if r <= 0.1 || corners == (false, false, false, false) {
+            pc.rect_with_radius_corners(qc, qx, qy, qw, qh, 0.0, (false, false, false, false));
+            continue;
+        }
+
+        let extra_corners = (
+            corners.0 && qx <= wx + 0.1 && qy <= wy + 0.1,
+            corners.1 && qx + qw >= wx + www - 0.1 && qy <= wy + 0.1,
+            corners.2 && qx + qw >= wx + www - 0.1 && qy + qh >= wy + whh - 0.1,
+            corners.3 && qx <= wx + 0.1 && qy + qh >= wy + whh - 0.1,
+        );
+
+        if extra_corners == (false, false, false, false) {
+            pc.rect_with_radius_corners(qc, qx, qy, qw, qh, 0.0, (false, false, false, false));
+        } else {
+            pc.rect_with_radius_corners(qc, qx, qy, qw, qh, r, extra_corners);
+        }
     }
     let font_opt = w.widget_font();
     for (label, bounds) in w.text_labels_with_bounds(ctx) {