refactor: move built-in icon upload into imgui backend

editor/src/UI/BuiltInIconLayoutUtils.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <imgui.h>
+
+#include <algorithm>
+
+namespace XCEngine {
+namespace Editor {
+namespace UI {
+
+inline ImVec2 ComputeFittedIconSize(
+    int textureWidth,
+    int textureHeight,
+    const ImVec2& min,
+    const ImVec2& max) {
+    const float availableWidth = max.x - min.x;
+    const float availableHeight = max.y - min.y;
+    if (availableWidth <= 0.0f || availableHeight <= 0.0f || textureWidth <= 0 || textureHeight <= 0) {
+        return ImVec2(0.0f, 0.0f);
+    }
+
+    const float scale = (std::min)(
+        availableWidth / static_cast<float>(textureWidth),
+        availableHeight / static_cast<float>(textureHeight));
+    return ImVec2(
+        static_cast<float>(textureWidth) * scale,
+        static_cast<float>(textureHeight) * scale);
+}
+
+} // namespace UI
+} // namespace Editor
+} // namespace XCEngine