Change placement of new floating windows

canonical · Jan 12, 2024 · ff77f3f · ff77f3f
1 parent a632621
commit ff77f3f
Showing 1 changed file with 86 additions and 0 deletions.
diff --git a/src/miral/basic_window_manager.cpp b/src/miral/basic_window_manager.cpp
@@ -29,6 +29,8 @@
 #include <boost/throw_exception.hpp>
 
 #include <algorithm>
+#include <random>
+#include <unordered_set>
 
 using namespace mir;
 using namespace mir::geometry;
@@ -2016,6 +2018,90 @@ auto miral::BasicWindowManager::place_new_surface(WindowSpecification parameters
 
         if (parameters.top_left().value().y < display_area.top_left.y)
             parameters.top_left() = Point{parameters.top_left().value().x, display_area.top_left.y};
+
+        if (parameters.state() == mir_window_state_restored)
+        {
+            Displacement const cascading_offset{48, 48};
+            Displacement const position_tolerance{12, 12};
+
+            auto unique_window_positions{[&]()
+            {
+                struct PointHash
+                {
+                    std::size_t operator() (Point const& point) const
+                    {
+                        std::size_t seed{};
+                        boost::hash_combine(seed, point.x.as_value());
+                        boost::hash_combine(seed, point.y.as_value());
+                        return seed;
+                    }
+                };
+                std::unordered_set<Point, PointHash> unique_positions;
+                for_each_application([&](ApplicationInfo& info)
+                {
+                    for (auto const& window : info.windows())
+                    {
+                        unique_positions.insert(window.top_left());
+                    }
+                });
+                return unique_positions;
+            }()};
+
+            auto const find_near_window_position{[&](Point const& point, Displacement const& tolerance)
+            {
+                return std::find_if(
+                    unique_window_positions.begin(),
+                    unique_window_positions.end(),
+                    [&](auto const& it)
+                    {
+                        return std::abs(it.x.as_value() - point.x.as_value()) <= tolerance.dx.as_value() &&
+                               std::abs(it.y.as_value() - point.y.as_value()) <= tolerance.dy.as_value();
+                    });
+            }};
+
+            auto new_position{parameters.top_left().value()};
+
+            auto near_window_position{find_near_window_position(new_position, position_tolerance)};
+            while (near_window_position != unique_window_positions.end())
+            {
+                unique_window_positions.erase(near_window_position);
+                new_position += cascading_offset;
+                near_window_position = find_near_window_position(new_position, position_tolerance);
+            }
+
+            if (!display_area.contains(new_position + as_displacement(parameters.size().value())))
+            {
+                Rectangle const placement_region{
+                    display_area.top_left,
+                    as_size(display_area.bottom_right() -
+                        as_displacement(parameters.size().value()) -
+                        as_displacement(display_area.top_left) + Displacement{1, 1})};
+                if (placement_region.size.width.as_value() > 0 && placement_region.size.height.as_value() > 0)
+                {
+                    std::random_device rd;
+                    std::default_random_engine gen(rd());
+                    std::uniform_int_distribution<int> dist_x(0, placement_region.size.width.as_value() - 1);
+                    std::uniform_int_distribution<int> dist_y(0, placement_region.size.height.as_value() - 1);
+                    new_position = placement_region.top_left + as_displacement(Point{dist_x(gen), dist_y(gen)});
+                }
+                else
+                {
+                    if(placement_region.size.width.as_value() <= 0)
+                    {
+                        new_position = Point{display_area.left(), new_position.y};
+                        parameters.size().value().width = display_area.size.width;
+                    }
+                    if(placement_region.size.height.as_value() <= 0)
+                    {
+                        new_position = Point{new_position.x, display_area.top()};
+                        parameters.size().value().height = display_area.size.height;
+                    }
+                }
+
+            }
+
+            parameters.top_left() = new_position;
+        }
     }
 
     return parameters;