layout: rethonk layouts from the ground up (#12890)

Rewrites layouts to be much smaller, and deal with much less annoying
BS. Improves the overall architecture, unifies handling of pseudotiling,
and various other improvements.

1 files changed, 54 insertions, 0 deletions

diff --git a/src/layout/algorithm/ModeAlgorithm.hpp b/src/layout/algorithm/ModeAlgorithm.hpp
new file mode 100644
index 00000000..90d7ce58
--- /dev/null
+++ b/src/layout/algorithm/ModeAlgorithm.hpp
@@ -0,0 +1,54 @@
+#pragma once
+
+#include "../../helpers/math/Math.hpp"
+#include "../../helpers/math/Direction.hpp"
+#include "../../helpers/memory/Memory.hpp"
+
+#include "../LayoutManager.hpp"
+
+#include <expected>
+
+namespace Layout {
+
+    class ITarget;
+    class CAlgorithm;
+
+    class IModeAlgorithm {
+      public:
+        virtual ~IModeAlgorithm() = default;
+
+        // a completely new target
+        virtual void newTarget(SP<ITarget> target) = 0;
+
+        // a target moved into the algorithm (from another)
+        virtual void movedTarget(SP<ITarget> target, std::optional<Vector2D> focalPoint = std::nullopt) = 0;
+
+        // a target removed
+        virtual void removeTarget(SP<ITarget> target) = 0;
+
+        // a target is being resized by a delta. Corner none likely means not interactive
+        virtual void resizeTarget(const Vector2D& Δ, SP<ITarget> target, eRectCorner corner = CORNER_NONE) = 0;
+
+        // recalculate layout
+        virtual void recalculate() = 0;
+
+        // swap targets
+        virtual void swapTargets(SP<ITarget> a, SP<ITarget> b) = 0;
+
+        // move a target in a given direction
+        virtual void moveTargetInDirection(SP<ITarget> t, Math::eDirection dir, bool silent) = 0;
+
+        // optional: handle layout messages
+        virtual std::expected<void, std::string> layoutMsg(const std::string_view& sv);
+
+        // optional: predict new window's size
+        virtual std::optional<Vector2D> predictSizeForNewTarget();
+
+      protected:
+        IModeAlgorithm() = default;
+
+        WP<CAlgorithm> m_parent;
+
+        friend class Layout::CAlgorithm;
+    };
+}
\ No newline at end of file