Each sprite has an anchorPoint property, or an origin. The anchorPoint property allows you to choose which part of the sprite aligns to the sprite's overall position.

To illustrate this, let's examine the blue square sprite we just drew on the screen. Our sprite is 50 points wide and 50 points tall, and its position is (150,150). Since we have not modified the anchorPoint property, its anchor point is (0.5,0.5). This means that the sprite will be perfectly centered over the (150,150) position on the scene's grid. Our sprite's left edge begins at 125 and the right edge terminates at 175. Likewise, the bottom starts at 125 and the top ends at 175. The following diagram illustrates our block's position on the grid:

Why do we prefer centered sprites by default? You may think it's simpler to position elements by their bottom-left corner with an anchorPoint property setting of (0,0). However, the centered behavior benefits us when we scale or rotate sprites:

There are some cases where you will want to change an anchor point. For instance, if you are drawing a rocket ship, you may want the ship to rotate around the front nose of its cone rather than its center.