refactored example by Robin

src/lib/include/paradiso/bitmap_io.hpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2023 Hartmut Seichter
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#ifndef PARADISO_BITMAP_IO_HPP
+#define PARADISO_BITMAP_IO_HPP
+
+#include <paradiso/bitmap.hpp>
+
+#include <string_view>
+#include <memory>
+
+namespace paradiso {
+
+struct BitmapIO {
+
+    static BitmapIO& get();
+
+    Bitmap load(std::string_view filename, bool ignore_cache = false) const;
+
+    void set_path(std::string_view path);
+
+    std::string path() const;
+
+  private:
+
+    struct Impl;
+    std::unique_ptr<Impl> impl_;
+
+    BitmapIO();
+    ~BitmapIO() = default;
+    BitmapIO(const BitmapIO&) = delete;
+    BitmapIO(BitmapIO&&) = delete;
+};
+
+} // namespace paradiso
+
+#endif