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1 files changed, 88 insertions, 0 deletions

diff --git a/CruUI/ui/controls/linear_layout.cpp b/CruUI/ui/controls/linear_layout.cpp
new file mode 100644
index 00000000..f639720d
--- /dev/null
+++ b/CruUI/ui/controls/linear_layout.cpp
@@ -0,0 +1,88 @@
+#include "linear_layout.h"
+
+namespace cru::ui::controls
+{
+    LinearLayout::LinearLayout(const Orientation orientation)
+        : Control(true), orientation_(orientation)
+    {
+
+    }
+
+    Size LinearLayout::OnMeasure(const Size& available_size)
+    {
+        const auto layout_params = GetLayoutParams();
+
+        if (!layout_params->Validate())
+            throw std::runtime_error("LayoutParams is not valid. Please check it.");
+
+        auto&& get_available_length_for_child = [](const MeasureLength& layout_length, const float available_length) -> float
+        {
+            switch (layout_length.mode)
+            {
+            case MeasureMode::Exactly:
+            {
+                return std::min(layout_length.length, available_length);
+            }
+            case MeasureMode::Stretch:
+            case MeasureMode::Content:
+            {
+                return available_length;
+            }
+            default:
+                UnreachableCode();
+            }
+        };
+
+        Size total_available_size_for_children(
+            get_available_length_for_child(layout_params->width, available_size.width),
+            get_available_length_for_child(layout_params->height, available_size.height)
+        );
+
+        auto rest_available_size_for_children = total_available_size_for_children;
+
+        ForeachChild([this, &rest_available_size_for_children](Control* const control)
+        {
+            control->Measure(rest_available_size_for_children);
+            if (orientation_ == Orientation::Horizontal)
+                rest_available_size_for_children.width -= control->GetDesiredSize().width;
+            else
+                rest_available_size_for_children.height -= control->GetDesiredSize().height;
+        });
+
+        auto actual_size_for_children = total_available_size_for_children - rest_available_size_for_children;
+
+        auto&& calculate_final_length = [](const MeasureLength& layout_length, const float length_for_children, const float max_child_length) -> float
+        {
+            switch (layout_length.mode)
+            {
+            case MeasureMode::Exactly:
+            case MeasureMode::Stretch:
+                return length_for_children;
+            case MeasureMode::Content:
+                return max_child_length;
+            default:
+                UnreachableCode();
+            }
+        };
+
+        return Size(
+            calculate_final_length(layout_params->width, total_available_size_for_children.width, actual_size_for_children.width),
+            calculate_final_length(layout_params->height, total_available_size_for_children.height, actual_size_for_children.height)
+        );
+    }
+
+    void LinearLayout::OnLayout(const Rect& rect)
+    {
+        auto current_anchor = Point::zero;
+        ForeachChild([this, &current_anchor](Control* control)
+        {
+            const auto size = control->GetDesiredSize();
+            control->Layout(Rect(current_anchor, size));
+
+            if (orientation_ == Orientation::Horizontal)
+                current_anchor.x += size.width;
+            else
+                current_anchor.y += size.height;
+        });
+    }
+}