L.4.9.4.3 Geometry Guides

A guide within a shape is essentially an equation with a set number of inputs and a single output. A guide is used to calculate construction values for a shape and thus can be manipulated to govern the shape’s overall geometry.

An example of this can be seen in the following DrawingML.

<gdLst>
  <gd name="y1" fmla="*/ h adj1 100"/>
</gdLst>

This guide calculates it’s output based on 3 input parameters and assign this output to a guide named y1. The formula that is used in the calculation here is the multiply divide formula. The result for this guide is calculated in the following manner: y1 = ((h * adj1) / 100). After the result here is calculated, the guide y1 can be used later within the or to calculate further values. That is it can be used as an input for calculating another guide value. These guides then allow for a path to be based off of series of equations rather than static path coordinate values. To use a guide in the defining of a path we would simply specify the following within the path list.

<a:lnTo>
  <a:pt x="2" y="y1"/>
</a:lnTo>

This would draw a line to the point (2,y1) where y1 is the calculated result of the guide equation shown above. The drawing of this line then changes based on the input parameters of h and adj1 which are previously calculated guides as well.

Note that while h is a previously calculated guide. It is not calculated for each shape, rather it is a built-in guide that the generating application makes available to the shape.

Subsections

• L.4.9.4.3.1 Adjust Handles