How to animate data visualization in Processing? - processing

Question

I'm trying to create an animated data visualization and currently only know how to do the following "static" code, which puts a string of dots in a straight line. How do I make them jump up and down? Also, if there is anyone in Dublin, Ireland, who wouldn't mind giving a few tutorial sessions to a couple of college students working on a data visualization project in Processing, we have a small budget to compensate you for your time. Thanks very much!
For now, here's the code I was talking about...
SimpleSpreadsheetManager sm;
String sUrl = "t6mq_WLV5c5uj6mUNSryBIA";
String googleUser = "USERNAME";
String googlePass = "PASSWORD";
void setup() {
//This code happens once, right when our sketch is launched
size(800,800);
background(0);
smooth();
//Ask for the list of numbers
int[] numbers = getNumbers();
fill(255,40);
noStroke();
for (int i = 0; i < numbers.length; i++) {
ellipse(numbers[i] * 8, width/2, 8,8);
};
};
void draw() {
//This code happens once every frame.
};

Answer 1

Essentially the x position you use for drawing the ellipse is a number value you get from external data. You need a variable that changes value. Redrawing the ellipse at the updated value should get things animated.
Take this basic example:
float x,y;//position variables for the ellipse
void setup(){
size(800,800);
smooth();
fill(255,40);
noStroke();
y = 400;
}
void draw(){
//update values
x = mouseX + (sin(frameCount * .05) * 30);//update x to an arbitrary value
//draw
background(0);//clear the screen for the new frame
ellipse(x,y,8,8);//draw the ellipse at the new position
}
the x variable is a bit like numbers[i] - just a value that chances.
Nothing special happens in draw() other than clearing the screen(by calling background()) and drawing. The example above uses an arbitrary value, but with your setup that might be something else, maybe a certain value in a data set that changes in time (like the population of a country, etc.)
Another handy thing to keep in mind is the separation between the data and visuals code wise. If values in the data set are higher than what can be displayed on screen as raw values, you can map() values so they can be viewer, add some sort of navigation controls, etc. The values analysed will not be affected by what's being displayed. In programming terms this separation between the data/model, the visuals/view (how the data is rendered) and the controls/controller is known as the Model-View-Controller pattern.
This might be a bit much for people just starting with code, but just being aware of the separation without worrying to much on the specific implementation can be helpful.
Here's a very basic example having the width of the sketch mapped to the size of the data (numbers)
SimpleSpreadsheetManager sm;
String sUrl = "t6mq_WLV5c5uj6mUNSryBIA";
String googleUser = "USERNAME";
String googlePass = "PASSWORD";
int[] numbers;//data used for visualisation
void setup() {
//sketch setup
size(800,800);
smooth();
fill(255,40);
noStroke();
//retrieve data
numbers = getNumbers();
}
void draw() {
background(0);
int numId = int(map(mouseX,0,width,0,numbers.length));//map mouse x position based on sketch width and data size
ellipse(numbers[numId] * 8, height/2, 8,8);
}

Answer 2

For an animation you need one or more parameters that their values changed in time, currently there is a library for processing which do such things: Ani
For more information see the site and provided examples.