处理3.0.1：滚动RSS源的最佳方式

Question

我是Processing的新手，我试图通过组合一些内置示例来开始。我正在通过图片滚动来自Google新闻的RSS源。它似乎工作得很好但代码仅限于一次滚动一个标题。如果我想限制每个标题之间的空间怎么办？我想到了两种方法：首先是将headlines转换成一个非常长的字符串。第二个是同时滚动两个headlines。第二种方法的问题在于，如果我继续更大的图像或开始滚动较小的字符串（如股票报价），我需要有许多语句来滚动许多headlines。有没有更好的方法，我没有想到？

/**
 * Scrolling Rss Feeds
 * 
 * Scroll headlines from Google News on top of an image
 */

PImage img;  // Declare variable "a" of type PImage
float x;  // horizontal location of headline
XML xml;
String[] headlines;
int index = 0;

void setup() {
  size(640, 360);
  x = width;
  // The image file must be in the data folder of the current sketch 
  // to load successfully
  img = loadImage("moonwalk.jpg");  // Load the image into the program 

  // The URL for the XML document
  String url = "http://news.google.com/news?cf=all&hl=en&pz=1&ned=us&output=rss";
  // Load the XML document
  xml = loadXML(url);
  // Grab the element we want
  XML[] headers = xml.getChildren("channel/item/title");
  headlines = new String[headers.length];
  for (int i = 0; i < headers.length; i++) {
     headlines[i] = headers[i].getContent();
  }
}

void draw() {
  // Displays the image at its actual size at point (0,0)
  image(img, 0, 0);
  textSize(32);
  text(headlines[index], x, 90);
  x = x - 3;
  float w = textWidth(headlines[index]);
  if (x < -w) {
    x = width; 
    index = (index + 1) % headlines.length;
  }
}