Remap event positions on rotated display

If the display is rotated, the position of clicks must be adapted.

app/src/input_manager.c

@@ -442,15 +442,46 @@ input_manager_process_key(struct input_manager *im,
     }
 }
 
+static struct point
+rotate_position(struct screen *screen, int32_t x, int32_t y) {
+    unsigned rotation = screen->rotation;
+    assert(rotation < 4);
+
+    int32_t w = screen->content_size.width;
+    int32_t h = screen->content_size.height;
+    struct point result;
+    switch (rotation) {
+        case 0:
+            result.x = x;
+            result.y = y;
+            break;
+        case 1:
+            result.x = h - y;
+            result.y = x;
+            break;
+        case 2:
+            result.x = w - x;
+            result.y = h - y;
+            break;
+        case 3:
+            result.x = y;
+            result.y = w - x;
+            break;
+        default:
+            assert(!"Unreachable");
+    }
+    return result;
+}
+
 static bool
 convert_mouse_motion(const SDL_MouseMotionEvent *from, struct screen *screen,
                      struct control_msg *to) {
     to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
     to->inject_touch_event.action = AMOTION_EVENT_ACTION_MOVE;
     to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
     to->inject_touch_event.position.screen_size = screen->frame_size;
-    to->inject_touch_event.position.point.x = from->x;
-    to->inject_touch_event.position.point.y = from->y;
+    to->inject_touch_event.position.point =
+        rotate_position(screen, from->x, from->y);
     to->inject_touch_event.pressure = 1.f;
     to->inject_touch_event.buttons = convert_mouse_buttons(from->state);
 
@@ -490,8 +521,9 @@ convert_touch(const SDL_TouchFingerEvent *from, struct screen *screen,
     to->inject_touch_event.pointer_id = from->fingerId;
     to->inject_touch_event.position.screen_size = frame_size;
     // SDL touch event coordinates are normalized in the range [0; 1]
-    to->inject_touch_event.position.point.x = from->x * frame_size.width;
-    to->inject_touch_event.position.point.y = from->y * frame_size.height;
+    float x = from->x * frame_size.width;
+    float y = from->y * frame_size.height;
+    to->inject_touch_event.position.point = rotate_position(screen, x, y);
     to->inject_touch_event.pressure = from->pressure;
     to->inject_touch_event.buttons = 0;
     return true;
@@ -526,8 +558,8 @@ convert_mouse_button(const SDL_MouseButtonEvent *from, struct screen *screen,
 
     to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
     to->inject_touch_event.position.screen_size = screen->frame_size;
-    to->inject_touch_event.position.point.x = from->x;
-    to->inject_touch_event.position.point.y = from->y;
+    to->inject_touch_event.position.point =
+        rotate_position(screen, from->x, from->y);
     to->inject_touch_event.pressure = 1.f;
     to->inject_touch_event.buttons =
         convert_mouse_buttons(SDL_BUTTON(from->button));