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Month: January 2009

JavaFX, easy use of tiles

Continuing my little JavaFX framework for game development, right now focused on use those tiles I’m drawing and posting here in my blog. This framework will be a group of classes for simplify and hide some complexities of common game development. Right now I wrote just a few of them.


We create a tileset from the files.png file that way

var tileset = Tileset {
    cols: 15 rows: 10 height: 32 width: 32
    image: Image {
        url: "{__DIR__}tiles.png"


Tileset are orthogonal, distributed into a grid of cols columns and rows rows. Each tile have dimensions height x width.

A Tileset is used into a Tilemap

var bg = Tilemap {
    set:tileset cols:5 rows:5
    map: [8,8,8,8,8,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3]

That shows

bg tilemap

Each number in the map represents a tile in the tilemap. Number 0 means the first tile at the upper left corner, numbers keep growing from left to right columns, from top to bottom rows.

Another example

var things = Tilemap {
    set:tileset cols:5 rows:5
    map: [80,55,56,145,145,96,71,72,61,62,0,0,0,77,78,122,0,0,93,94,138,0,0,0,0]

things tileset

A tilemap can also contains more than one layer

var room = Tilemap {
    set:tileset cols:5 rows:5 layers:2
    map: [



The Tileset class basically stores a Image and a collection of Rectangle2D objects, for be used as viewports in ImageView classes.

import javafx.scene.image.ImageView;
import javafx.scene.image.Image;
import javafx.geometry.Rectangle2D;

public class Tileset {
    public-init var      image: Image;
    public-init var      width: Integer = 32;
    public-init var     height: Integer = 32;
    public-init var       rows: Integer = 10;
    public-init var       cols: Integer = 15;
    protected   var       tile: Rectangle2D[];

    init {
        tile =  for (row in [0..rows]) {
            for (col in [0..cols]) {
                    minX: col * width, minY: row * height
                    height: width, width: height

The Tilemap is a CustomNode with a Group of ImageViews in a grid. The grid is mounted by iterating over the map as many layers was defined.

public class Tilemap extends CustomNode {
    public-init var   rows: Integer = 10;
    public-init var   cols: Integer = 10;
    public-init var    set: Tileset;
    public-init var layers: Integer = 1;
    public-init var    map: Integer[];

    public override function create(): Node {
        var tilesperlayer = rows * cols;
        return Group {
                for (layer in [0..layers]) {
                    for (row in [0..rows-1]) {
                        for (col in [0..cols-1]) {
                            ImageView {
                                image: set.image x: col * set.width y: row * set.height
                                viewport: set.tile[map[tilesperlayer*layer + row*rows+col]]

Next steps

  • Integrate to a map editor
  • Support some XML map format
  • Sprite classes for animation
  • Integrate those collision detection classes I posted before


Easily encrypt files with Gnu Privacy Guard

gnupg logo

Gpg is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool to provide digital encryption and signing services  using  the  OpenPGP  standard.

To easily encrypt a file called mydocs use:

gpg -c mydocs

You’ll be propted twice for a password, after that a encrypted file called mydocs.gpg is created. You can send this file to your it’s destine and send the password using some secure way. In the other side to decrypt the file:

gpg mydocs.gpg

That’s a very simple use of this tool, you can do much more.

Reading Twitter with JavaFX

twitter bird

Twitter is a social network and micro-blogging service that allow you to create and read tweets, 140 characters text-based posts. It’s becoming a popular tool to keep in touch with your friends, coworkers, bloggers, etc. Here we’ll create a very simple application that show us tweets related with a given word.

Twitter offers a very simple and powerfull REST API which supports XML, JSON, and the RSS and Atom formats. As we are aiming just to read tweets we’ll use just the Search API.

We do that in three steps:

  1. Query Tweets
  2. Parser the Atom result
  3. Show tweets into a GUI

Let’s see them in the order of dependence beetween them.

Displaying a Tweet

var gradient = LinearGradient {
    startX: 0.0,
    startY: 0.0,
    endX: 0.0,
    endY: 150.0
    proportional: false
    stops: [Stop {offset: 0.0 color: Color.DARKGRAY },
        Stop { offset: 1.0 color: Color.BLACK }]

public class Tweet extends CustomNode {
    public var image: Image;
    public var username: String;
    public var message: String;
    public override function create(): Node {
        var txt = Text {
            x: 65  y: 35 wrappingWidth: 150 fill: Color.WHITE
            content: "{message}"
        return Group {
            content: [
                Rectangle {
                    width: 220 height: txt.boundsInLocal.height + 40
                    arcHeight: 10 arcWidth: 10 fill: gradient
                ImageView {
                    x: 5 y: 20 image: image
                Text {
                    x: 65  y: 20 fill: Color.BLACK content: "{username} said"

For example, this tweet would become:

tweet example

Parsing ATOM result

In my last post about JavaFX I showed how to parse XML documents (and make sandwiches) with JavaFX. Here we’ll use the Atom format, but use any other would be almost the same. Parsing XML or JSON documents with JavaFX is both very simple using the class.

A query output is a Atom XML document with several information. We are interested only in the fields that holds the avatar image, the message and the user name.

var tweets = VBox {}
def parser = PullParser {
    var avatar;
    var firstname;
    var text;
    documentType: PullParser.XML;

    onEvent: function(event: Event) {
        if(event.type == PullParser.START_ELEMENT){
                if(event.getAttributeValue(QName{name: "rel"}) == "image"){
                    avatar = event.getAttributeValue(QName{name:"href"});

        if(event.type == PullParser.END_ELEMENT) {
            if( == "title"){
                    text = event.text;
            if(( == "name")and(event.level==3)){
                var names: String[] = event.text.split(" ");
                firstname = names[0];
                insert Tweet {
                        image: Image {
                            url: avatar
                        message: text
                        username: firstname
                    } into tweets.content;

Querying Tweets

We can get Atom results through url queries like that:

Notice that queries should be URL encoded. We will use a additional parameters &rpp=4 to receive only 4 results per page. To know more about search queries read the Search API Documentation. We get these results as InputStreams making asynchronous HTTP requests using the class, which it’s perfect to invoke RESTful Web Services.

word = "Beatles";
var request = HttpRequest {
    location: "{word}&rpp=4";
    onInput: function(stream: {
        parser.input = stream;


Here is the application running for the word “House”.

twitter with javafx

Is not a complete Twitter client, as it’s not intended to be, but can show you how to handle a simple asynchronous call and handle Twitter documents. There’s already a few beta JavaFX Twitter clients like Tweetbox and Twitterfx and certanly others will appears.


Sources and Netbeans project, fxtwitter.tar.bz2.

CEJUG Pizza Party

We had our OSUM Pizza Party and it was just great. We had a lot of delicious food and drinks. All paid by SUN OSUM as a prize for we become one of the Century Clubs, firsts communities to have more than 100 members in our OSUM.

Levantem os brindes
Everybody got some gift

A JavaFX application to select random numbers for prizes

brindesSome prizes

Banner do CEJUG
CEJUG Banner

More photos at this album.

Thanks for all friends that was there. Was a great celebration.