Sorted out the animation vs. easing contradiction I believe. Now there's a separate easing_duration that's calculated from the total duration of all frames. Then a easing_position determines where in the total the animation is, which is fed to the asing functions as a ration of easing_position / easing_duration.

animate2.hpp

@@ -29,6 +29,7 @@ namespace animate2 {
     double current_time = 0.0;
     double frame_duration = 0.0;
     double alpha = 0.0;
+    int elapsed_ticks = 0;
     sf::Clock clock{};
 
     std::pair<int, double> commit();
@@ -40,12 +41,14 @@ namespace animate2 {
 
   struct Sequence {
     std::vector<int> frames{};
-    std::vector<std::chrono::milliseconds> durations{};
+    std::vector<int> durations{}; // in ticks
     size_t current{0};
     int loop_count{0};
     size_t frame_count{0};
     Timer timer{};
-    float subframe{0.0f};
+    int subframe{0};
+    float easing_duration{0.0f};
+    float easing_position{0.0f};
   };
 
   struct Transform {
@@ -55,7 +58,6 @@ namespace animate2 {
     float max_x{1.0f};
     float max_y{1.0f};
     bool flipped{false};
-    float ease_rate{0.5f};
     bool scaled{false};
     bool relative{false};
 
@@ -123,7 +125,6 @@ namespace animate2 {
       void update();
       void motion(sf::Transformable& sprite, sf::Vector2f pos, sf::Vector2f scale);
       void motion(sf::View& view_out, sf::Vector2f pos, sf::Vector2f scale);
-      std::pair<int, double> commit();
   };
 
   Animate2 load(const std::string &file, const std::string &anim_name);
@@ -131,6 +132,6 @@ namespace animate2 {
   ENROLL_COMPONENT(Sheet, frames, frame_width, frame_height);
   ENROLL_COMPONENT(Sequence, frames, durations);
   ENROLL_COMPONENT(Transform, min_x, min_y, max_x, max_y,
-      flipped, ease_rate, scaled, relative, toggled, looped, easing, motion);
+      flipped, scaled, relative, toggled, looped, easing, motion);
   ENROLL_COMPONENT(Animate2, sheet, sequences, transforms, forms, sounds);
 }