2 files changed, 51 insertions, 1 deletions
diff --git a/src/anim.cpp b/src/anim.cpp
new file mode 100644
index 00000000..f4850deb
--- /dev/null
+++ b/src/anim.cpp
@@ -0,0 +1,33 @@
+#include "anim.hpp"
+#include "compat/exception.hpp"
+#include <cmath>
+
+namespace floormat {
+
+Vector2ui anim_scale::scale_to(Vector2ui image_size) const
+{
+    fm_soft_assert(image_size.product() > 0);
+    Vector2ui ret;
+    switch (type)
+    {
+    default:
+        fm_throw("invalid anim_scale_type '{}'"_cf, (unsigned)type);
+    case anim_scale_type::invalid:
+        fm_throw("anim_scale is invalid"_cf);
+    case anim_scale_type::fixed:
+        fm_soft_assert(f.width_or_height > 0);
+        if (f.is_width)
+            ret = { f.width_or_height, (unsigned)std::round((float)f.width_or_height * (float)image_size.y()/(float)image_size.x()) };
+        else
+            ret = { (unsigned)std::round((float)f.width_or_height * (float)image_size.x()/(float)image_size.y()), f.width_or_height };
+        break;
+    case anim_scale_type::ratio:
+        fm_soft_assert(r.f > 0 && r.f <= 1);
+        ret = { (unsigned)std::round(image_size.x() * r.f), (unsigned)std::round(image_size.y() * r.f) };
+        break;
+    }
+    fm_soft_assert(ret.product() > 0);
+    return ret;
+}
+
+} // namespace floormat
diff --git a/src/anim.hpp b/src/anim.hpp
index 674895ed..a8fb63a3 100644
--- a/src/anim.hpp
+++ b/src/anim.hpp
@@ -28,6 +28,22 @@ struct anim_group final
     Vector3b offset;
 };
 
+enum class anim_scale_type : std::uint8_t { invalid, ratio, fixed, };
+
+struct anim_scale final
+{
+    struct ratio { float f; };
+    struct fixed { bool is_width; unsigned width_or_height; };
+    struct empty {};
+    union {
+        struct ratio r;
+        struct fixed f;
+        struct empty e = {};
+    };
+    anim_scale_type type = anim_scale_type::invalid;
+    Vector2ui scale_to(Vector2ui image_size) const;
+};
+
 struct anim_def final
 {
     static constexpr int default_fps = 24;
@@ -35,7 +51,8 @@ struct anim_def final
     String object_name, anim_name;
     std::vector<anim_group> groups;
     Vector2ui pixel_size;
-    std::size_t nframes = 0, width = 0, height = 0, fps = default_fps, actionframe = 0;
+    anim_scale scale;
+    std::size_t nframes = 0, fps = default_fps, actionframe = 0;
 };
 
 } // namespace floormat