抽象多媒体类, 修复gtest问题

include/imageService.h

@@ -0,0 +1,18 @@
+#include <SFML/Graphics.hpp>
+#include <algorithm>
+
+class ImageService {
+private:
+    sf::Texture texture;
+public:
+    ImageService(const std::string& name){
+        texture.loadFromFile(name);
+    }
+    sf::Texture& GetTexture(){
+        return texture;
+    }
+    float GetScale(int width, int height){
+        auto imgSize = texture.getSize();
+        return std::min(static_cast<float>(width) / imgSize.x, static_cast<float>(height) / imgSize.y);
+    }
+};