add internal holes detection in jump-hop image processing

server-rs/crates/platform-image/src/generated_asset_sheets/alpha.rs

@@ -38,6 +38,10 @@ pub struct GeneratedAssetSheetAlphaOptions {
     pub key_color: GeneratedAssetSheetKeyColor,
     pub remove_near_white_background: bool,
     pub remove_disconnected_hard_key_background: bool,
+    // 中文注释：检测并清除被主体包围、不与画布四边连通的品红镂空区域。
+    // 仅对独立连通域整体判定，通过 min_pixels 过滤微小噪点。
+    pub detect_internal_holes: bool,
+    pub internal_hole_min_pixels: usize,
 }
 
 impl GeneratedAssetSheetAlphaOptions {
@@ -46,6 +50,8 @@ impl GeneratedAssetSheetAlphaOptions {
             key_color: GeneratedAssetSheetKeyColor::GREEN_SCREEN,
             remove_near_white_background: true,
             remove_disconnected_hard_key_background: true,
+            detect_internal_holes: false,
+            internal_hole_min_pixels: 0,
         }
     }
 
@@ -54,6 +60,8 @@ impl GeneratedAssetSheetAlphaOptions {
             key_color: GeneratedAssetSheetKeyColor::MAGENTA_SCREEN,
             remove_near_white_background: false,
             remove_disconnected_hard_key_background: false,
+            detect_internal_holes: true,
+            internal_hole_min_pixels: 16,
         }
     }
 }
@@ -216,6 +224,66 @@ fn remove_generated_asset_sheet_green_screen_background(
         }
     }
 
+    // 中文注释：内部镂空洞检测——寻找与四边不连通、被主体包围的品红区域。
+    // 必须在软 matte 扩展之前执行，避免软扩展跨越窄前景通道误判。
+    if options.detect_internal_holes && options.internal_hole_min_pixels > 0 {
+        let mut hole_visited = vec![false; pixel_count];
+        let mut hole_queue = Vec::<usize>::new();
+
+        for start_index in 0..pixel_count {
+            if background_mask[start_index] != 0
+                || key_scores[start_index] < GENERATED_ASSET_SHEET_GREEN_SCREEN_MIN_SCORE
+                || hole_visited[start_index]
+            {
+                continue;
+            }
+
+            // 中文注释：BFS 收集当前候选背景连通域
+            hole_queue.clear();
+            hole_queue.push(start_index);
+            hole_visited[start_index] = true;
+            let mut component = Vec::<usize>::new();
+            let mut touches_border = false;
+            let mut queue_cursor = 0usize;
+
+            while queue_cursor < hole_queue.len() {
+                let pixel_index = hole_queue[queue_cursor];
+                queue_cursor += 1;
+                component.push(pixel_index);
+
+                let x = pixel_index % width;
+                let y = pixel_index / width;
+                if x == 0 || x == width.saturating_sub(1) || y == 0 || y == height.saturating_sub(1) {
+                    touches_border = true;
+                }
+
+                let neighbors = [
+                    if x > 0 { Some(pixel_index - 1) } else { None },
+                    if x + 1 < width { Some(pixel_index + 1) } else { None },
+                    if y > 0 { Some(pixel_index - width) } else { None },
+                    if y + 1 < height { Some(pixel_index + width) } else { None },
+                ];
+
+                for next in neighbors.into_iter().flatten() {
+                    if background_mask[next] != 0 || hole_visited[next] {
+                        continue;
+                    }
+                    if key_scores[next] < GENERATED_ASSET_SHEET_GREEN_SCREEN_MIN_SCORE {
+                        continue;
+                    }
+                    hole_visited[next] = true;
+                    hole_queue.push(next);
+                }
+            }
+
+            if !touches_border && component.len() >= options.internal_hole_min_pixels {
+                for pixel_index in component {
+                    background_mask[pixel_index] = 1;
+                }
+            }
+        }
+    }
+
     let soft_green_cleanup_rounds = (width.min(height) / 40).clamp(4, 14);
     for _ in 0..soft_green_cleanup_rounds {
         let mut expanded_mask = background_mask.clone();