Allows you change the pinned corner of the rectangle.
The Pin property can take any of the following values:
- 0 - bottom left (the default)
- 1 - top left
- 2 - bottom right
- 3 - top right
Some operations require that the rectangle be pinned to a
location. For example, if you want to change the width of a
rectangle, you can do this either by shifting the left side or the
right side. If the pin property is set to the bottom left or top
left, then the left side of the rectangle will be kept fixed and
the right side shifted. Conversely, if the pin property is set to
the bottom right or top right, then the right side of the rectangle
will be kept fixed and the left side shifted.