Question

Beginner rails/javascript question:

Let’s say that I have a simple Circle model in a Rails 3.1 app with a show action/view. Each Circle has a property called :radius – an integer value.

When I view the Circle via its show.html.erb file, I want a very simple processing.js sketch to receive the radius of the circle and draw the circle on the page. I’ve already included processing.js in my app by saving the file in the assets/javascripts folder.

My simple processing.js sketch is in a file called circle.js. Its contents are:

// Setup the Processing Canvas  
void setup(){  
  size( 200, 200 );  
  strokeWeight( 10 );  
  frameRate( 15 );  
  X = width / 2;  
  Y = height / 2;
  radius = 10;      
}  

// Main draw loop  
void draw(){    
  // Fill canvas grey  
  background( 100 );  

  // Set stroke-color white  
  stroke(255);   

  // Draw circle  
  ellipse( X, Y, radius, radius );                    
}  

1. How do I include the sketch into my show view as unobtrusively as possible and pass the radius value to it?
2. Where does the circle.js file go — in the view folder or in the asset pipeline?
3. Does it need to be named circle.js.erb?

Answer 1

You can put circle.js into app/assets/javascripts. It doesn’t need to be called circle.js.erb, but it could be.