fix(computer-use): surround cursor with a soft contour shadow

src/apps/desktop/src/computer_use/macos_capture.m

@@ -615,22 +615,26 @@ - (void)drawRect:(NSRect)rect {
     [arrow transformUsingAffineTransform:size];
     arrow.lineWidth = 3;
     arrow.lineJoinStyle = NSLineJoinStyleRound;
-    [NSGraphicsContext saveGraphicsState];
-    NSShadow *shadow = [[NSShadow alloc] init];
-    shadow.shadowColor = [NSColor colorWithWhite:0 alpha:0.45];
-    shadow.shadowBlurRadius = 3;
-    // This view is flipped, so positive Y places the shadow below the cursor.
-    shadow.shadowOffset = NSMakeSize(0, 2);
-    [shadow set];
-    // Cast one shadow from the complete silhouette, including its white edge.
-    CGContextRef context = NSGraphicsContext.currentContext.CGContext;
-    CGContextBeginTransparencyLayer(context, NULL);
-    [[NSColor colorWithSRGBRed:64.0/255 green:64.0/255 blue:64.0/255 alpha:1] setFill];
-    [arrow fill];
-    [NSColor.whiteColor setStroke];
-    [arrow stroke];
-    CGContextEndTransparencyLayer(context);
-    [NSGraphicsContext restoreGraphicsState];
+    // A broad halo plus a denser contact shadow, both centered on the complete
+    // silhouette. Zero offset keeps the falloff even around every white edge.
+    const CGFloat blur[] = {5, 1.5};
+    const CGFloat opacity[] = {0.5, 0.8};
+    for (NSUInteger layer = 0; layer < 2; ++layer) {
+        [NSGraphicsContext saveGraphicsState];
+        NSShadow *shadow = [[NSShadow alloc] init];
+        shadow.shadowColor = [NSColor colorWithWhite:0 alpha:opacity[layer]];
+        shadow.shadowBlurRadius = blur[layer];
+        shadow.shadowOffset = NSZeroSize;
+        [shadow set];
+        CGContextRef context = NSGraphicsContext.currentContext.CGContext;
+        CGContextBeginTransparencyLayer(context, NULL);
+        [[NSColor colorWithSRGBRed:64.0/255 green:64.0/255 blue:64.0/255 alpha:1] setFill];
+        [arrow fill];
+        [NSColor.whiteColor setStroke];
+        [arrow stroke];
+        CGContextEndTransparencyLayer(context);
+        [NSGraphicsContext restoreGraphicsState];
+    }
 }
 @end
 static NSPanel *obfPointerPanel;

src/apps/desktop/src/computer_use/windows_pointer_feedback.rs

@@ -219,21 +219,30 @@ fn pointer_pixels(clicked: bool) -> Vec<u32> {
         }
     }
     let weights: Vec<f64> = (-5..=5)
-        .map(|n| (-(f64::from(n).powi(2)) / (2.0 * 1.5 * 1.5)).exp())
+        .map(|n| (-(f64::from(n).powi(2)) / (2.0 * 2.0 * 2.0)).exp())
+        .collect();
+    let edge_weights: Vec<f64> = (-5..=5)
+        .map(|n| (-(f64::from(n).powi(2)) / (2.0 * 0.65 * 0.65)).exp())
         .collect();
     let sum: f64 = weights.iter().sum();
+    let edge_sum: f64 = edge_weights.iter().sum();
     let mut pixels = vec![0u32; 1600];
     for y in 0..40i32 {
         for x in 0..40i32 {
             let mut shadow = 0.0;
+            let mut edge_shadow = 0.0;
             for dy in -5..=5 {
                 for dx in -5..=5 {
-                    let (mx, my) = (x - dx, y - 2 - dy);
+                    let (mx, my) = (x - dx, y - dy);
                     if (0..40).contains(&mx) && (0..40).contains(&my) {
-                        shadow += mask[(my * 40 + mx) as usize]
-                            * weights[(dx + 5) as usize]
-                            * weights[(dy + 5) as usize]
-                            / (sum * sum);
+                        let coverage = mask[(my * 40 + mx) as usize];
+                        shadow +=
+                            coverage * weights[(dx + 5) as usize] * weights[(dy + 5) as usize]
+                                / (sum * sum);
+                        edge_shadow += coverage
+                            * edge_weights[(dx + 5) as usize]
+                            * edge_weights[(dy + 5) as usize]
+                            / (edge_sum * edge_sum);
                     }
                 }
             }
@@ -247,7 +256,9 @@ fn pointer_pixels(clicked: bool) -> Vec<u32> {
             } else {
                 0.0
             };
-            let behind = ring + shadow * 0.45 * (1.0 - ring);
+            // Center both layers: dark beside the white edge, softer farther out.
+            let halo = edge_shadow * 0.8 + shadow * 0.5 * (1.0 - edge_shadow * 0.8);
+            let behind = ring + halo * (1.0 - ring);
             let alpha = silhouette + behind * (1.0 - silhouette);
             let channel =
                 (64.0 * fill + 255.0 * stroke + 166.0 * ring * (1.0 - silhouette)).round() as u32;
@@ -433,5 +444,25 @@ mod tests {
         assert!(pixels.iter().all(|p| p & 255 <= p >> 24));
         assert_eq!(pixels[0], 0);
         assert_ne!(pixels, pointer_pixels(true));
+        // The contour is diagonal-symmetric; directional shadow offsets must
+        // not bias one side. Outside each edge, black fades toward transparency.
+        for y in 0..40 {
+            for x in 0..40 {
+                assert_eq!(pixels[y * 40 + x], pixels[x * 40 + y]);
+            }
+        }
+        for ray in [
+            [(12, 5), (12, 4), (12, 3)],
+            [(5, 12), (4, 12), (3, 12)],
+            [(28, 16), (29, 16), (30, 16)],
+            [(16, 28), (16, 29), (16, 30)],
+        ] {
+            let alpha = ray.map(|(x, y)| {
+                let pixel = pixels[y * 40 + x];
+                assert_eq!(pixel & 0xffffff, 0);
+                pixel >> 24
+            });
+            assert!(alpha[0] > alpha[1] && alpha[1] > alpha[2] && alpha[2] > 0);
+        }
     }
 }

src/web-ui/src/app/components/ComputerUseControlCard.scss

@@ -47,7 +47,10 @@
       stroke: var(--openbitfun-color-content-on-dark);
       stroke-width: 3px;
       stroke-linejoin: round;
-      filter: drop-shadow(0 2px 3px color-mix(in srgb, var(--openbitfun-color-content-on-light) 45%, transparent));
+      // Centered contour shadows: a dark contact edge with a wider soft halo.
+      filter:
+        drop-shadow(0 0 1px color-mix(in srgb, var(--openbitfun-color-content-on-light) 80%, transparent))
+        drop-shadow(0 0 4px color-mix(in srgb, var(--openbitfun-color-content-on-light) 50%, transparent));
     }
 
   }