Grapher

Grapher displays one or more numeric values on a moving graph for easy visualization. This plugin might be most useful to teachers who are helping others to learn about Isadora.

Grapher was created by Isadora’s creator Mark Coniglio specifically for his workshop “What Do We Do With the Data?” at the Isadora Werkstatt 2019.

If anything is unclear about these instructions, or if you have a problem using this actor, please let us know by making a post in the forum. One of our team, or one of the members of our awesome community, will be there to help.

Apple silicon (ARM/M1)

The macOS version of this plugin has been compiled to run natively on both Intel-based and Apple silicon based computers.

Instructions

Remember, you can see helpful instructions for any actor by mousing over the actor’s inputs or outputs and seeing what appears in the Help View at the bottom right of the main Isadora window. But here is a quick summary of Grapher’s inputs and what they do.

Try Out the Grapher Actor

Let’s start with a simple example.

1) Connect a numeric input to ‘value 1’ input – you could use the output of a Mouse Watcher or a Wave Generator actor to give this actor a try.
2) Connect the ‘video out’ to a projector and Show Stages to see the graphed output.

You’ll see that the value received at ‘value 1’ is being drawn onto the graph, and that the graph slides to the right as time passes, as you might see on a heart monitor or chart recorder.

Set the Vertical Range

The vertical range for the graph is set by the ‘range min’ and ‘range max’ inputs, which default to -100 and +100. If you’re using the Mouse Watcher, you’d want to set ‘range min’ to 0 so that Grapher’s range matches the range of the Mouse Watcher.

If the value you are receiving is small (e.g., -0.1 to +0.1) then you’d want to use those values for ‘range min’ and ‘range max’ so that the representation of the signal fills the entire graph vertically.

Set the Time Scale

The amount of time represented by the entire width of the graph is set by the ‘time scale input, which is given in seconds. If you want to see the last 20 seconds of data in the output, set this input to 20.

Working with Multiple Values

If you want to graph multiple values:

1) Set the ‘values’ input to the number of values you require.
2) Additional ‘value’ inputs to which you can connect other values will appear below ‘value 1’
3) You will see a line for each ‘value’ input drawn in the graph.

To see this in action, set ‘values’ to 2 and connect the two outputs of a Mouse Watcher to the ‘value 1’ and ‘value 2’ inputs.

Usually, when you are graphing multiple values, you’ll want to set the ‘color min’ and ‘color max’ inputs to two different colors so each line in the graph will be a different color. For the greatest variation, pure red and pure blue are a good choices for these inputs. If you do this, the first line in the graph will be red, the last line will be blue, and the lines in between will show equally spaced colors between ‘min color’ and ‘max color’.

Other Parameters

The ‘line size’ controls the size of the lines drawn in the graph, while the ‘grid lines’ and ‘grid size’ inputs allow you to draw equally spaced divisions on the horizontal axis.

The ‘width’ and ‘height’ inputs determine the resolution of the output image, which is usually sent to a Projector actor but can be passed to any Isadora actor that accepts video input. You can enter any values you like here to control the aspect ratio and resolution of the output graph. We’ve found the default 1280 x 720 work quite well.