topLeftPositionCalculation method

Offset topLeftPositionCalculation(
  1. Size buttonSize,
  2. Size popupSize,
  3. Offset offset
)

Calculate the location from (0, 0) of the screen if the menu is located at the top left of the dropdown button. Given the location of the button (offset), the size of the popup menu, and the size of the dropdown menu button, calculate location of the menu.

Implementation

Offset topLeftPositionCalculation(
    Size buttonSize, Size popupSize, Offset offset) {
  return Offset(
    offset.dx - popupSize.width,
    offset.dy - popupSize.height,
  );
}