The Document Coordinate System

To first specify a shape within a document the document coordinate system must be understood. This system has both an x and y component and starts with a value of (0,0) in the upper left corner of the document. As the x-coordinate increases, the point will move to the right. As the y-coordinate increases, the point will move downwards. The units of measurement within the document coordinate system are EMUs (91440 EMUs/U.S. inch, 36000 EMUs/cm). In addition to specifying a position for the shape, you must also specify the width and height of the shape, which is called the extent of the shape. This value is again measured in EMUs. To specify these two values, the following transform would be used.

<p:sp>
  <p:spPr>
    <a:xfrm>
      <a:off x="3200400" y="1600200"/>
      <a:ext cx="1200000" cy="1000000"/>
    </a:xfrm>
  </p:spPr>
</p:sp>

Here we can see that this new shape will be placed at x = 3200400 and y = 1600200 within the document coordinate system. In addition, we see that this shape will have a width of 1200000 EMUs and a height of 1000000 EMUs.

The width and height set the bounding box within which the entire shape will be contained.