internal static Vector3 ScreenToWorldDistance(SceneView view, Vector2 delta)
{
// Ensures that the camera matrix doesn't end up with gigantic or minuscule values in the clip to world matrix
const float k_MaxCameraSizeForWorldToScreen = 2.5E+7f;
// store original camera and view values
var camera = view.camera;
var near = camera.nearClipPlane;
var far = camera.farClipPlane;
var pos = camera.transform.position;
var size = view.size;
// set camera transform and clip values to safe values
view.size = Mathf.Min(view.size, k_MaxCameraSizeForWorldToScreen);
// account for the distance clamping
var scale = size / view.size;
var clip = view.GetDynamicClipPlanes();
view.camera.nearClipPlane = clip.x;
view.camera.farClipPlane = clip.y;
view.camera.transform.position = Vector3.zero;
// do the distance calculation
Vector3 pivot = camera.transform.rotation * new Vector3(0f, 0f, view.cameraDistance);
Vector3 screenPos = camera.WorldToScreenPoint(pivot);
screenPos += new Vector3(delta.x, delta.y, 0);
Vector3 worldDelta = camera.ScreenToWorldPoint(screenPos) - pivot;
worldDelta *= EditorGUIUtility.pixelsPerPoint * scale;
// restore original cam and scene values
view.size = size;
view.camera.nearClipPlane = near;
view.camera.farClipPlane = far;
view.camera.transform.position = pos;
return(worldDelta);
}