A GOOD MILESTONE : Refactor title bar and toolbar typography, improve tooltip styles, and enhance selection transform functionality

- Updated typography constants for menu bar and tooltips to improve readability and consistency.
- Adjusted button padding and widths in the title bar for better layout.
- Replaced tooltip implementation with a new balloon tooltip style for improved visual feedback.
- Enhanced selection transform logic to support rotation and resizing, ensuring accurate hit testing and bounds calculations.
- Added tests for selection clearing and transformed bounds to ensure functionality and prevent regressions.
- Introduced a new module for managing selection transform dirty bounds during interactive previews.

hcie-engine-api/src/lib.rs

@@ -3400,11 +3400,32 @@ impl Engine {
     }
 
     /// Clear pixels only within the active selection mask. If no selection, clears all.
+    /// Records a full-layer draw snapshot so the operation is undoable.
     pub fn clear_selection_pixels(&mut self) {
-        let mask = self.cached_selection_mask.clone();
+        let mask = self.document.selection_mask.clone();
+        let active_idx = self.document.active_layer;
+        log::debug!(
+            "[Engine::clear_selection_pixels] active_layer={}, selection_active={}, document_mask_len={:?}, stroke_cache_mask_len={:?}",
+            active_idx,
+            self.document.selection_active,
+            mask.as_ref().map(Vec::len),
+            self.cached_selection_mask.as_ref().map(Vec::len),
+        );
         if let Some(ref mask_data) = mask {
             let w = self.document.canvas_width as usize;
             let h = self.document.canvas_height as usize;
+            let selected_pixels = mask_data.iter().filter(|coverage| **coverage > 0).count();
+            log::debug!(
+                "[Engine::clear_selection_pixels] clearing selected region: canvas={}x{}, selected_pixels={}",
+                w,
+                h,
+                selected_pixels,
+            );
+            let before_pixels = self
+                .document
+                .active_layer()
+                .map(|layer| layer.pixels.clone())
+                .unwrap_or_default();
             if let Some(layer) = self.document.active_layer_mut() {
                 for y in 0..h {
                     for x in 0..w {
@@ -3418,14 +3439,45 @@ impl Engine {
                     }
                 }
                 layer.dirty = true;
-                self.document.composite_dirty = true;
-                self.document.modified = true;
             }
+            self.document.push_draw_snapshot(
+                active_idx,
+                before_pixels,
+                None,
+                "Clear Selection".to_string(),
+            );
+            self.document.composite_dirty = true;
+            self.document.modified = true;
         } else {
-            self.clear_active_layer_pixels();
+            log::debug!(
+                "[Engine::clear_selection_pixels] no active document mask; clearing the entire active layer"
+            );
+            self.clear_active_layer_pixels_undoable();
         }
     }
 
+    /// Clears the entire active layer and records an undo snapshot.
+    pub fn clear_active_layer_pixels_undoable(&mut self) {
+        let active_idx = self.document.active_layer;
+        let before_pixels = self
+            .document
+            .active_layer()
+            .map(|layer| layer.pixels.clone())
+            .unwrap_or_default();
+        if let Some(layer) = self.document.active_layer_mut() {
+            layer.pixels.fill(0);
+            layer.dirty = true;
+        }
+        self.document.push_draw_snapshot(
+            active_idx,
+            before_pixels,
+            None,
+            "Clear Layer".to_string(),
+        );
+        self.document.composite_dirty = true;
+        self.document.modified = true;
+    }
+
     pub fn set_active_layer_pixels(&mut self, pixels: Vec<u8>) {
         if let Some(layer) = self.document.active_layer_mut() {
             layer.pixels = pixels;