add splitbox ui element

src/graphics/ui/elements/SplitBox.cpp

@@ -0,0 +1,62 @@
+#include "SplitBox.hpp"
+
+using namespace gui;
+
+SplitBox::SplitBox(const glm::vec2& size, float splitPos, Orientation orientation)
+ : Container(size), splitPos(splitPos), orientation(orientation) {
+    setCursor(
+        orientation == Orientation::vertical ? CursorShape::NS_RESIZE
+                                             : CursorShape::EW_RESIZE
+    );
+}
+
+void SplitBox::mouseMove(GUI*, int x, int y) {
+    auto pos = calcPos();
+    auto size = getSize();
+    
+    glm::ivec2 cursor(x - pos.x, y - pos.y);
+    int axis = orientation == Orientation::vertical;
+
+    int v = cursor[axis];
+    v = std::max(std::min(static_cast<int>(size[axis]) - 10, v), 10);
+    float t = v / size[axis];
+    splitPos = t;
+
+    refresh();
+}
+
+void SplitBox::refresh() {
+    Container::refresh();
+
+    if (nodes.empty()) {
+        return;
+    }
+    glm::vec2 size = getSize();
+    if (nodes.size() == 1) {
+        auto node = nodes.at(0);
+        node->setPos(glm::vec2());
+        node->setSize(size);
+        return;
+    }
+    auto nodeA = nodes.at(0);
+    auto nodeB = nodes.at(1);
+    
+    nodeA->setPos(glm::vec2());
+    if (orientation == Orientation::vertical) {
+        float splitPos = this->splitPos * size.y;
+        nodeA->setSize(glm::vec2(size.x, splitPos - splitRadius));
+        nodeB->setSize(glm::vec2(size.x, size.y - splitPos - splitRadius));
+        nodeB->setPos(glm::vec2(0.0f, splitPos + splitRadius));
+    } else {
+        float splitPos = this->splitPos * size.x;
+        nodeA->setSize(glm::vec2(splitPos - splitRadius, size.y));
+        nodeB->setSize(glm::vec2(size.x - splitPos - splitRadius, size.y));
+        nodeB->setPos(glm::vec2(splitPos + splitRadius, 0.0f));
+    }
+}
+
+void SplitBox::fullRefresh() {
+    refresh();
+    reposition();
+    Container::fullRefresh();
+}