refactor: move built-in icon upload into imgui backend

tests/editor/CMakeLists.txt

@@ -11,6 +11,7 @@ set(EDITOR_TEST_SOURCES
     test_scene_viewport_picker.cpp
     test_scene_viewport_overlay_renderer.cpp
     test_viewport_host_surface_utils.cpp
+    test_builtin_icon_layout_utils.cpp
     ${CMAKE_SOURCE_DIR}/editor/src/Core/UndoManager.cpp
     ${CMAKE_SOURCE_DIR}/editor/src/Managers/SceneManager.cpp
     ${CMAKE_SOURCE_DIR}/editor/src/Managers/ProjectManager.cpp

tests/editor/test_builtin_icon_layout_utils.cpp

@@ -0,0 +1,40 @@
+#include <gtest/gtest.h>
+
+#include "UI/BuiltInIconLayoutUtils.h"
+
+namespace {
+
+using XCEngine::Editor::UI::ComputeFittedIconSize;
+
+TEST(BuiltInIconLayoutUtilsTest, ReturnsZeroWhenTextureOrBoundsAreInvalid) {
+    EXPECT_EQ(
+        ComputeFittedIconSize(0, 64, ImVec2(0.0f, 0.0f), ImVec2(64.0f, 64.0f)).x,
+        0.0f);
+    EXPECT_EQ(
+        ComputeFittedIconSize(64, 64, ImVec2(10.0f, 0.0f), ImVec2(10.0f, 64.0f)).y,
+        0.0f);
+}
+
+TEST(BuiltInIconLayoutUtilsTest, FitsWidthLimitedRegions) {
+    const ImVec2 size = ComputeFittedIconSize(
+        256,
+        128,
+        ImVec2(0.0f, 0.0f),
+        ImVec2(64.0f, 64.0f));
+
+    EXPECT_FLOAT_EQ(size.x, 64.0f);
+    EXPECT_FLOAT_EQ(size.y, 32.0f);
+}
+
+TEST(BuiltInIconLayoutUtilsTest, FitsHeightLimitedRegions) {
+    const ImVec2 size = ComputeFittedIconSize(
+        128,
+        256,
+        ImVec2(0.0f, 0.0f),
+        ImVec2(80.0f, 40.0f));
+
+    EXPECT_FLOAT_EQ(size.x, 20.0f);
+    EXPECT_FLOAT_EQ(size.y, 40.0f);
+}
+
+} // namespace