Restore dbox behavior from ftxui5.0.0

Bug:https://github.com/eclipse-ecal/ecal/pull/2095

CHANGELOG.md

@@ -4,6 +4,10 @@ Changelog
 Future release
 ------------
 
+### dom
+- Bugfix: Restore the `dbox` behavior from ftxui 5.0.0. To apply bgcolor
+  blending between the two layers, a new `dboxBlend` will be added.
+
 6.1.8 (2025-05-01)
 ------------------
 

src/ftxui/dom/dbox.cpp

@@ -45,59 +45,6 @@ class DBox : public Node {
       child->SetBox(box);
     }
   }
-
-  void Render(Screen& screen) override {
-    if (children_.size() <= 1) {
-      Node::Render(screen);
-      return;
-    }
-
-    const int width = box_.x_max - box_.x_min + 1;
-    const int height = box_.y_max - box_.y_min + 1;
-    std::vector<Pixel> pixels(std::size_t(width * height));
-
-    for (auto& child : children_) {
-      child->Render(screen);
-
-      // Accumulate the pixels
-      Pixel* acc = pixels.data();
-      for (int x = 0; x < width; ++x) {
-        for (int y = 0; y < height; ++y) {
-          auto& pixel = screen.PixelAt(x + box_.x_min, y + box_.y_min);
-          acc->background_color =
-              Color::Blend(acc->background_color, pixel.background_color);
-          acc->automerge = pixel.automerge || acc->automerge;
-          if (pixel.character.empty()) {
-            acc->foreground_color =
-                Color::Blend(acc->foreground_color, pixel.background_color);
-          } else {
-            acc->blink = pixel.blink;
-            acc->bold = pixel.bold;
-            acc->dim = pixel.dim;
-            acc->inverted = pixel.inverted;
-            acc->italic = pixel.italic;
-            acc->underlined = pixel.underlined;
-            acc->underlined_double = pixel.underlined_double;
-            acc->strikethrough = pixel.strikethrough;
-            acc->hyperlink = pixel.hyperlink;
-            acc->character = pixel.character;
-            acc->foreground_color = pixel.foreground_color;
-          }
-          ++acc;  // NOLINT
-
-          pixel = Pixel();
-        }
-      }
-    }
-
-    // Render the accumulated pixels:
-    Pixel* acc = pixels.data();
-    for (int x = 0; x < width; ++x) {
-      for (int y = 0; y < height; ++y) {
-        screen.PixelAt(x + box_.x_min, y + box_.y_min) = *acc++;  // NOLINT
-      }
-    }
-  }
 };
 }  // namespace