GravityBlast » Development

Don’t abuse NSLog in your iPhone game

Andrea Franz — Thu, 08 Apr 2010 08:12:49 +0000

I’m working on a simple game for iPhone based on cocos2d. Yesterday I installed it on my old iPhone3G and it was veeeeeeeery slow. After a lot of refactoring I found a NSLog call inside my game loop. It basically logged all the collision detection of the player with all the tiles in the map. After removing that it’s even faster then before. So, if you want to log something, do it, but remember to remove all these logging calls later.

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Using CouchDB from Air applications with CouchDB Flex

Andrea Franz — Tue, 03 Nov 2009 14:31:37 +0000

In the last weeks I played a lot with CouchDB and I love it. I always used it from ruby but yesterday I tried to use it with flex. I started a new Actionscript project called CouchDB Flex, you can browse the source from github. The implementation is inspired by couchrest, but it’s asynchronous because I use URLLoader internally. Since the flash player doesn’t support the PUT and DELETE HTTP methods, you must create an AIR project if you want to try the library. You can find a compiled swc here, put it in your libs folder and you are ready to go. Here a small example, but it’s still in development, and a lot of functionality are not implemented yet.

CouchdbFlexExample.mxml: the main mxml file, it’s just a window with a textarea that will display the data loaded from CouchDB.

xml version="1.0" encoding="utf-8"?>
<c:App xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:c="com.gravityblast.couchdbflexexample.*">
  <s:TextArea id="textarea" width="100%" height="100%" text="{log}"/>			
c:App>

com/gravityblast/couchdbflexexample/Contact.as: the model I’ll save on CouchDB. By default the model has a name and an email, but I can add more properties since it’s a dynamic class.

package com.gravityblast.couchdbflexexample
{
  import com.gravityblast.couchdb.Document;
 
  public dynamic class Contact extends Document
  {		
    public var name:String;
    public var email:String;
 
    public function Contact()
    {
      super();
    }
  }
}

com/gravityblast/couchdbflexexample/App.as: the main application, where I create a new Contact Document, and I load all the contacts using a view created with the Design and View classes.

package com.gravityblast.couchdbflexexample
{
  import com.gravityblast.couchdb.CouchDb;
  import com.gravityblast.couchdb.Database;
  import com.gravityblast.couchdb.Design;
  import com.gravityblast.couchdb.View;
  import com.gravityblast.couchdb.events.CouchRestEvent;
  import com.gravityblast.couchdb.events.DocumentEvent;
  import com.gravityblast.couchdb.events.ViewEvent;
 
  import mx.events.FlexEvent;
 
  import spark.components.TextArea;
  import spark.components.WindowedApplication;
 
  public class App extends WindowedApplication
  {		
    private var couchdb:CouchDb;
    private var database:Database;
 
    [Bindable]
    public 	var log:String;
    public 	var textarea:TextArea;
 
    public function App()
    {			
      this.couchdb = new CouchDb();
      this.database = this.couchdb.database("couchdb-flex-example");
      this.log = "";
      this.addEventListener(FlexEvent.CREATION_COMPLETE, this.creationCompleteHandler);
      super();
    }
 
    private function creationCompleteHandler(event:FlexEvent):void
    {			
      this.database.create(this.databaseCreateHandler);	
    }
 
    private function databaseCreateHandler(event:CouchRestEvent):void
    {
      trace(event.data);
      if (event.json.ok || event.json.error.toString() == "file_exists")
      {
        var map:String = "function(doc) {if (doc['couchdb-flex-type'] == 'com.gravityblast.couchdbflexexample::Contact') emit(null, doc);}";
        var view:View = new View("all", map);
        var design:Design = new Design("contacts");
        design.addView(view);
        design.save(this.designSaveHandler);	
      }
    }
 
    private function designSaveHandler(event:DocumentEvent):void
    {
      trace(event.data);									
      if (event.json.ok || event.json.error == "conflict")			
        this.createContacts();
      else
        trace("Error saving design document: " + event.data)			
    }
 
    private function createContacts():void
    {
      var contact:Contact = new Contact();
      contact.name    = "jack";
      contact.email   = "jack@example.com";
      contact.address = "Jack Street";
      contact.save(this.contactSaveHandler);			
    }
 
    private function contactSaveHandler(event:DocumentEvent):void
    {			
      trace(event.data);
      var contact:Contact = event.document as Contact;
      contact.address = "Jack Street updated at " + (new Date()).toString();
      contact.save(this.contactUpdateHandler);			
    }
 
    private function contactUpdateHandler(event:DocumentEvent):void
    {			
      trace(event.data);
      View.load("contacts", "all", {}, this.contactsLoadHandler);
    }
 
    private function contactsLoadHandler(event:ViewEvent):void
    {					
      for each (var contact:Contact in event.documents)
      {
        for (var property:String in contact.attributes)
        {
          this.log += property + ": " + contact[property] + "\n";	
        }
        this.log += "-------------\n";
      }
    }
  }
}

I’ll write more about the library as soon as it’s more stable.

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Flex functional testing with FunFx and Cucumber

Andrea Franz — Thu, 20 Aug 2009 13:11:56 +0000

Cucumber is a great tool I usually use for BDD in my ruby projects, but yesterday I tried it with Flex, and it was very enjoyable. Here a little example on how to test Flex applications with Cucumber.

First of all you need ruby, then you need to install the following gems:

sudo gem install rspec cucumber watir safariwatir funfx

(I used the following codes on mac os x, with ruby 1.8.6, safari 4.0.3 and funx 0.2.2)

After that open Flex Builder and create a new project called CucumberExample and use the following code for your main mxml file:

xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
	<mx:Number id="index">0mx:Number>
	<mx:VBox width="300" height="200" backgroundColor="white">
		<mx:HBox width="100%" height="30">			
			<mx:Button id="buttonDecrement" label="-" width="100%" />
			<mx:Button id="buttonIncrement" label="+" width="100%" />
		mx:HBox>
		<mx:HBox width="100%" height="100%" verticalAlign="middle" horizontalAlign="center">
			<mx:Label id="myLabel" text="{index}"/>			
		mx:HBox>
	mx:VBox>
mx:Application>

As you can see, we have a number, 2 buttons and a label. Now create a directory called features inside your flex project folder and create the first Cucumber feature file, called counter:

CucumberExample/features/counter.feature:

Feature: Counter
  In order to count something
  As a flex rock star
  I want to use my great flex app
 
  Scenario: Increment index
    Given I open my flex app
    And I click the increment button
    Then the label text should be "1"
    When I click the decrement button
    Then the label text should be "0"
    When I click the decrement button
    Then the label text should be "-1"

It’s a test written in pure plain text.

In the features folder create another folder called step_definitions with a blank file called counter_steps.rb, we’ll use it later.

Now open the console, go the to flex project root and run your test:

cd /path/to/CucumberExample
cucumber features

You should see something like this:

...
1 scenario (1 undefined)
7 steps (7 undefined)
0m0.002s

You can implement step definitions for undefined steps with these snippets:

Given /^I open my flex app$/ do
  pending
end
 
Given /^I click the increment button$/ do
  pending
end
 
Then /^the label text should be "([^\"]*)"$/ do |arg1|
  pending
end
 
When /^I click the decrement button$/ do
  pending
end

Before implementing the steps above, we need to add the funfx component to our library.

Download the latest swc file from rubyforge and place it in your CucumberExample/libs folder (I used the version 0.2.2).

Duplicate the bin-debug folder and rename it to test (you have a bin-debug folder after the first time you run the CucumberExample from FlexBuilder).

Inside the test directory create a file called test_server.rb with the following content:

require 'webrick'
 
server = WEBrick::HTTPServer.new :Port => 9852, :DocumentRoot => File.dirname(__FILE__)
trap("INT"){ server.shutdown }
server.start

Now you need a compiled version of your project that includes funfx.We’ll use it just for testing:

build_test.sh

#!/bin/sh
FLEX_SDK_HOME="/Applications/Adobe Flex Builder 3/sdks/3.2.0"
"$FLEX_SDK_HOME/bin/mxmlc" -verbose-stacktraces -include-libraries ./libs/funfx-0.2.2.swc "$FLEX_SDK_HOME/frameworks/libs/automation.swc" "$FLEX_SDK_HOME/frameworks/libs/automation_dmv.swc"  "$FLEX_SDK_HOME/frameworks/libs/automation_agent.swc" -output ./test/CucumberExample.swf -- ./src/CucumberExample.mxml

Run test compile_test.sh

chmod 755 ./build_test.sh
./build_test.sh

Now open another terminal window and start the test server:

cd /path/to/CucumberExample/test
ruby test_server.rb

Open http://localhost:9852/CucumberExample.html with your browser and you should see your flex app.

Now you can come back to your features and implement the step we leave before. Here my implementation:

CucumberExample/features/step_definitions/counter_steps.rb

Given /^I open my flex app$/ do
  open_flex_app
end
 
Given /^I click the (increment|decrement) button$/ do |button|  
  click_button("button#{button.capitalize}")  
end
 
Then /^the label text should be "([^\"]*)"$/ do |text|
  label_text.should == text  
end

open_flex_app, click_button and label_text are methods defined in my env.rb file.

CucumberExample/features/support/env.rb

require "rubygems"
require 'funfx/browser/safariwatir'
 
module FlexWorld
  def open_flex_app
    @browser.goto("http://localhost:9852/CucumberExample.html")
  end
 
  def click_button(button_id)
    @flex_app.button(:id => button_id).click
  end
 
  def label_text
    @flex_app.label(:id => "myLabel").text
  end
end
 
Before do
  @browser  = Watir::Safari.new
  @flex_app = @browser.flex_app("CucumberExample", "CucumberExample")  
end
 
After do
  @browser.close
end
 
World(FlexWorld)

Now you are ready to run your tests. Start the test_server and then the features. You should have an error:

Then the label text should be "1"  # features/step_definitions/counter_steps.rb:9
      expected: "1",
           got: "0" (using ==)

This because we didn’t implement the functionality yet in our flex app. So, change the mxml file with the following:

xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
	<mx:Number id="index">0mx:Number>
	<mx:VBox width="300" height="200" backgroundColor="white">
		<mx:HBox width="100%" height="30">			
			<mx:Button id="buttonDecrement" label="-" width="100%" click="index--" />
			<mx:Button id="buttonIncrement" label="+" width="100%" click="index++" />
		mx:HBox>
		<mx:HBox width="100%" height="100%" verticalAlign="middle" horizontalAlign="center">
			<mx:Label id="myLabel" text="{index}"/>			
		mx:HBox>
	mx:VBox>
mx:Application>

It’s the same code but I added the click action to the increment and decrement buttons. Now compile the new code and run the features again:

./build_test.sh
cucumber features

You shoiuld have the following output, with all the seven steps passed:

Feature: Counter
  In order to count something
  As a flex rock star
  I want to use my great flex app
 
  Scenario: Increment index            # features/counter.feature:6
    Given I open my flex app           # features/step_definitions/counter_steps.rb:1
    And I click the increment button   # features/step_definitions/counter_steps.rb:5
    Then the label text should be "1"  # features/step_definitions/counter_steps.rb:9
    When I click the decrement button  # features/step_definitions/counter_steps.rb:5
    Then the label text should be "0"  # features/step_definitions/counter_steps.rb:9
    When I click the decrement button  # features/step_definitions/counter_steps.rb:5
    Then the label text should be "-1" # features/step_definitions/counter_steps.rb:9
 
1 scenario (1 passed)
7 steps (7 passed)
0m9.781s

If you have any problems you may want to clear the cache from safari.

I used the funfx gem from rubyforge but it’s not up to date. If you want you can get the new code from github, it should have new features.

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Hostname middleware for rails apps on multiple servers

Andrea Franz — Sat, 15 Aug 2009 22:37:36 +0000

If you run a rails application on multiple servers behind a load balancer, almost every time you make a request you have a response from a different host. If you want to know which host has sent back the response, you can use a middleware that adds the hostname in the page title of each request.

lib/hostname.rb:

class Hostname  
  TITLE_REGEXP = /(<title>)([^<]*)(<\/title>)/i
 
  def initialize(app, hostname="")
    @app          = app
    @title_suffix = " - on #{hostname}"
  end
 
  def call(env)
    status, headers, response = @app.call(env)
    add_hostname(response, headers) if headers["Content-Type"] =~ %r{text/html}
    [status, headers, response]
  end  
 
  def add_hostname(response, headers)
    response.each{|s| s.sub!(TITLE_REGEXP, "\\1\\2#{@title_suffix}\\3") if s =~ TITLE_REGEXP}
    headers["Content-Length"] = (headers["Content-Length"].to_i + @title_suffix.length).to_s
    nil
  end
end

To use it, add this line in your environment.rb:

config.middleware.use "Hostname", %x"hostname".chomp

When you don’t need it anymore you can simply remove the line above.

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Testing rails generators with Cucumber

Andrea Franz — Tue, 11 Aug 2009 13:43:59 +0000

In the last days I switched a lot of old projects to use Cucumber, then I started writing test for Web App Theme. Here I haven’t models or controllers to test, because it’s just a generator, but I found enjoyable the use of plain text features to describe the ThemeGenerator behavior:

Feature: Layout generation
  In order to create a great application
  I should be able to generate a layout with Web App Theme
 
  # script/generate theme
  Scenario: Generate a layout    
    Given I have a new rails app
    And I have no layouts
    And I have no stylesheets
    When I generate a theme
    Then I should have a layout named "application.html.erb"
    And I should have a stylesheet named "web_app_theme.css"
    And I should have a stylesheet named "web_app_theme_override.css"
    And I should have a stylesheet named "themes/default/style.css"
 
  # script/generate theme admin
  Scenario: Generate a layout with a name
    Given I have a new rails app
    And I have no layouts
    And I generate a theme with name "admin"
    Then I should have a layout named "admin.html.erb"
 
  # script/generate theme --theme="drastic-dark"
  Scenario: Generate a layout choosing a theme
    Given I have a new rails app
    And I have no stylesheets
    And I generate a theme choosing the "drastic-dark" theme
    Then I should have a stylesheet named "themes/drastic-dark/style.css"
 
  # script/generate theme --theme=bec --no_layout
  Scenario: Generate only stylesheets without layout
    Given I have a new rails app
    And I have no layouts
    And I generate a theme without layout choosing the "bec" theme
    Then I should have a stylesheet named "themes/bec/style.css"
    But I should not have any layouts
 
  # script/generate theme --app_name="My New Application"
  Scenario: Generate layout with application name
    Given I have a new rails app
    And I have no layouts
    And I generate a theme with application name "My New Application"
    Then the layout "application.html.erb" should have "My New Application" as page title
 
  # script/generate theme --type=sign
  Scenario: Generate layout for signin and signup
    Given I have a new rails app
    And I have no layouts
    And I generate a theme for signin and signup
    Then I should have a layout named "sign.html.erb"
    And I should have a layout named "sign.html.erb" with just a box

Here my steps:

Given /^I have a new rails app$/ do
  generate_rails_app
end
 
Given /^I have no layouts$/ do
  remove_layouts  
end
 
Given /^I have no stylesheets$/ do
  remove_stylesheets
end
 
Given /^I generate a theme$/ do
  generate_layout(:theme)  
end
 
Given /^I generate a theme with name "([^\"]*)"$/ do |name|
  generate_layout(:theme, name)
end
 
Given /^I generate a theme choosing the "([^\"]*)" theme$/ do |theme_name|
  generate_layout(:theme, :theme => theme_name)
end
 
Then /^I should have a layout named "([^\"]*)"$/ do |filename|
  layout_exists?(filename).should be_true  
end
 
Then /^I should have a stylesheet named "([^\"]*)"$/ do |filename|
  stylesheet_exists?(filename).should be_true    
end
 
Given /^I generate a theme without layout choosing the "([^\"]*)" theme$/ do |theme_name|
  generate_layout(:theme, :theme => theme_name, :no_layout => true )
end
 
Then /^I should not have any layouts$/ do
  layouts_count.should == 0
end
 
Given /^I generate a theme with application name "([^\"]*)"$/ do |name|
  generate_layout(:theme, :app_name => name )
end
 
Then /^the layout "([^\"]*)" should have "([^\"]*)" as page title$/ do |layout, title|
  layout_title(layout).should == title
end
 
Given /^I generate a theme for signin and signup$/ do
  generate_layout(:theme, :layout_type => :sign)
end
 
Then /^I should have a layout named "([^\"]*)" with just a box$/ do |layout|
  layout_with_box?(layout).should be_true
end

Basically I create a temp folder that I use as fake rails root, and there I launch the generator. After each feature I remove that folder.

And here my env.rb

$:.unshift(File.dirname(__FILE__) + "/../../rails_generators")
require "rubygems"
require "rails_generator"
require 'rails_generator/scripts/generate'
require "fileutils"
require "theme/theme_generator"
 
web_app_theme_root  = File.join(File.dirname(__FILE__), "/../../")
tmp_rails_app_name  = "tmp_rails_app"
tmp_rails_app_root  = File.join(web_app_theme_root, tmp_rails_app_name)
 
Rails::Generator::Base.append_sources(Rails::Generator::PathSource.new(:plugin, "#{web_app_theme_root}/rails_generators/"))
 
module GeneratorHelpers
  def generate_rails_app
    FileUtils.mkdir(File.join(@app_root))
  end    
 
  def remove_layouts
    FileUtils.rm_rf(File.join(@app_root, "app", "views", "layouts"))
  end
 
  def remove_stylesheets
    FileUtils.rm_rf(File.join(@app_root, "public", "stylesheets"))
  end
 
  def generate_layout(*args)
    options = !args.empty? && args.last.is_a?(Hash) ? args.pop : {}
    options.merge!({:destination => @app_root, :quiet => true})    
    Rails::Generator::Scripts::Generate.new.run(args, options)
  end
 
  def layouts_count
    Dir[File.join(@app_root, "app", "views", "layouts", "**", "*.erb")].size
  end
 
  def layout_exists?(filename)
    File.exists?(File.join(@app_root, "app", "views", "layouts", filename))
  end
 
  def stylesheet_exists?(relative_path)
    File.exists?(File.join(@app_root, "public", "stylesheets", relative_path)).should be_true
  end
 
  def layout_title(layout)
    File.open(File.join(@app_root, "app", "views", "layouts", layout), "r").read.match(/<title>([^<]*)<\/title>/)[1]
  end
 
  def layout_with_box?(layout)
    File.open(File.join(@app_root, "app", "views", "layouts", layout), "r").read =~ %r|<div id="box">|
  end
end
 
Before do
  @app_root = tmp_rails_app_root  
end
 
After do
  FileUtils.rm_rf(tmp_rails_app_root)
end
 
World(GeneratorHelpers)

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2 minutes admin layout with rails and the web-app-theme generator

Andrea Franz — Thu, 30 Jul 2009 14:02:19 +0000

Many people found out a rails generator inside my web-app-theme project and asked me how to use it.
Here an example, starting from scratch with a new rails app that manages music Albums.

rails cool_albums
cd cool_albums
script/generate scaffold Album name:string artist:string date:date
rake db:migrate

After creating the first controller with a scaffold or with your hands, start creating a theme:

script/plugin install git://github.com/pilu/web-app-theme.git
script/generate theme application --app_name="My Cool Albums" --theme="drastic-dark"

The first argument (“application”) is the name of the layout that the generator will create (application.html.erb).
The –app_name option specifies the name used as page title, and with the –theme specifies which theme to use among all the available themes inside the plugin.

Now remove the default index.html created by rails and the layout created by the scaffold:

rm app/views/layouts/albums.html.erb 
rm public/index.html

Add the following line in your routes.rb to set the default page of the application:

map.root :controller => :albums

Start the server

script/server

Ok, the layout has been successfully created, but we need to apply a theme for each one of the views generated by the scaffold.

script/generate themed albums album --layout=application --with_will_paginate

With the first 2 arguments I specified the controller path (albums) and the model used (album).
The –layout options is used by the themed generator to know where to add the Albums menu link.

Since we want to use will paginate (we set the –with_will_paginate option), we need to change one line in our albums controller from:

@albums = Album.all

to:

@albums = Album.paginate(:per_page => 10, :page => params[:page])

Here a trick to show form error messages inside the auto generated forms, you can add the following lines in your environment.rb:

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance| 
  if html_tag =~ /<label/
    %|<div class="fieldWithErrors">#{html_tag} #{[instance.error_message].join(', ')}

| else html_tag end end

Ok, restart your server and you are done.

Feel free to fork the project from github to improve the generator or to add a new theme.

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Creating PDF with images using flex and AlivePDF

Andrea Franz — Sun, 19 Jul 2009 00:25:39 +0000

Today I’m working on an AIR application, and I need to create a PDF starting from a list of images. This PDF needs to have one image for each page. I used AlivePDF, a very useful ActionScript3 library for PDF generation, and I created a simple class that takes an array of image paths and creates the PDF I need.

Here the class I use:

package
{	
  import flash.events.Event;
  import flash.events.EventDispatcher;
  import flash.filesystem.File;
  import flash.filesystem.FileMode;
  import flash.filesystem.FileStream;
  import flash.net.URLLoader;
  import flash.net.URLLoaderDataFormat;
  import flash.net.URLRequest;
  import flash.utils.ByteArray;
 
  import org.alivepdf.pdf.PDF;	
  import org.alivepdf.display.Display;
  import org.alivepdf.images.ResizeMode;
  import org.alivepdf.layout.Layout;
  import org.alivepdf.layout.Orientation;
  import org.alivepdf.layout.Size;
  import org.alivepdf.layout.Unit;
  import org.alivepdf.saving.Method;
 
  public class PdfGenerator extends EventDispatcher
  {		  
    private var pdf:PDF;
    private var images:Array;		
    private var outFilePath:String;
    private var completedPages:int;
 
    public function PdfGenerator(images:Array, outFilePath:String)
    {
      this.outFilePath = outFilePath;
      this.images = images;
    }				
 
    public function generate():void
    {						
      this.completedPages = 0;
      this.pdf = new PDF(Orientation.LANDSCAPE, Unit.MM, Size.A4);
      this.nextPage();		
    }
 
    private function nextPage():void
    {
      this.completedPages < this.images.length ? this.loadImage(this.images[this.completedPages++]) : this.save();
    }
 
    private function loadImage(path:String):void
    {						
      var urlLoader:URLLoader = new URLLoader();			
      urlLoader.dataFormat = URLLoaderDataFormat.BINARY;
      urlLoader.addEventListener(Event.COMPLETE, this.onImageLoadComplete);
      urlLoader.load(new URLRequest(path));						
    }
 
    private function onImageLoadComplete(event:Event):void
    {						
      this.pdf.addPage();
      this.pdf.addImageStream(ByteArray(event.target.data), 0, 0, 0, 0, 1, ResizeMode.FIT_TO_PAGE);
      this.dispatchEvent(new PdfGeneratorEvent(PdfGeneratorEvent.PDF_GENERATOR_PAGE_COMPLETE, false, false, this.images.length, this.completedPages));
      this.nextPage();
    }
 
    private function save():void
    {				
      this.pdf.end();
      this.writeOutFile();												
      this.dispatchEvent(new PdfGeneratorEvent(PdfGeneratorEvent.PDF_GENERATOR_COMPLETE));
    }
 
    private function writeOutFile():void
    {
      var fileStream:FileStream = new FileStream();								
      fileStream.open(new File(this.outFilePath), FileMode.WRITE);			
      fileStream.writeBytes(this.pdf.save(Method.LOCAL));
      fileStream.close();
    }
  }
}

Basically for each image it creates a new URLRequest and when the request is completed it adds a new page with the image. As you can see I also dispatch a custom Event called PdfGeneratorEvent. That because I need to create a PDF with a large number of images, and doing like this I can give a feedback to the user with a ProgressBar that display the generation progress.

package
{
  import flash.events.Event;
 
  public class PdfGeneratorEvent extends Event
  {			
    public static const PDF_GENERATOR_PAGE_COMPLETE:String = "PDF_GENERATOR_PAGE_COMPLETE";
    public static const PDF_GENERATOR_COMPLETE:String      = "PDF_GENERATOR_COMPLETE";			
 
    public var totalPages:int;
    public var completedPages:int;
 
    public function PdfGeneratorEvent(type:String, bubbles:Boolean=false, cancelable:Boolean=false, totalPages:int=0, completedPages:int=0)
    {			
      super(type, bubbles, cancelable);
      this.totalPages     = totalPages;
      this.completedPages = completedPages;
    }
  }
}

And here the main file that uses this class:

public function createPdf(images:Array):void
{
  var generator:PdfGenerator = new PdfGenerator(images, "/path/to/my/test.pdf");
  generator.addEventListener(PdfGeneratorEvent.PDF_GENERATOR_COMPLETE, this.onPdfComplete);
  generator.addEventListener(PdfGeneratorEvent.PDF_GENERATOR_PAGE_COMPLETE, this.onPdfPageComplete);				
  generator.generate();				
}
 
public function onPdfPageComplete(event:PdfGeneratorEvent):void
{					
  progressBar.setProgress(event.completedPages, event.totalPages);
  progressBar.label = event.completedPages + " of " + event.totalPages;															
}
 
public function onPdfComplete(event:PdfGeneratorEvent):void
{											
  trace("completed")
}

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Mask problem with flex canvas and drag & drop

Andrea Franz — Sun, 12 Jul 2009 23:34:37 +0000

Some weeks ago a spent a lot of time trying to fix a bug inside an AIR application I was working on.
I wrote a custom component that has an image as child. This image is draggable, and the container should act as a mask. The problem was that when I started dragging the picture, the picture went outside its container, like the following example.

Try dragging the red square outside the white one:

I fixed this bug just setting the scrollRect property to the container:

Only when I realized how to fix the bug I found another guy with the same problem and the same solution.

Here the code:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application width="500" height="300" xmlns:mx="http://www.adobe.com/2006/mxml" 
  layout="vertical" verticalAlign="middle" horizontalAlign="center"
  applicationComplete="init()">
  <mx:Script>
    [CDATA[												
      public function init():void
      {				
        this.container.scrollRect = new Rectangle(0, 0, this.container.width, this.container.height);																
        this.draggableCanvas.addEventListener(MouseEvent.MOUSE_UP, this.mouseUpHandler);				
        this.draggableCanvas.addEventListener(MouseEvent.MOUSE_DOWN, this.mouseDownHandler);
      }			
 
      private function mouseDownHandler(event:MouseEvent):void
      {
        this.draggableCanvas.startDrag();
      }
 
      private function mouseUpHandler(event:MouseEvent):void
      {
        this.draggableCanvas.stopDrag();
        }
    ]]>
  mx:Script>
  <mx:Canvas id="container" width="300" height="250" backgroundColor="white" horizontalScrollPolicy="off" verticalScrollPolicy="off">
    <mx:Canvas id="draggableCanvas" x="50" y="25" width="200" height="200" backgroundColor="#AA0000">			
    mx:Canvas>
  mx:Canvas>
mx:Application>

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2 things I like in prototype 1.6.1

Andrea Franz — Tue, 31 Mar 2009 13:11:02 +0000

The stable version of prototype is 1.6.0.3. I just fiddled around with the edge version (1.6.1_rc2) and I found 2 new features I really like. The first one is the Element#clone method. At last I can easily clone an element, or make a deep clone of it passing true as first argument:

<div id="genres">
  <div class="genre">
    <select name="genre[]">
      <option>Your favorite genre...</option>
      <option>Death Metal</option>
      <option>Black Metal</option>
      <option>Speed Metal</option>
    </select>
  </div>
</div>
<a id="add-genre" href="#">Add</a>

document.observe("dom:loaded", function() {
  $("add-genre").observe("click", function(event) {
    event.stop();
    var genres = $("genres"); 
    genres.insert(genres.down(".genre").clone(true));
  });
});

Just click the Add link to add a new the select tag.

Another cool new feature is the Element Storage. You can store any kind of data inside a element, and retrieve it when you need it.

Here an example:

<div id="items">
  <div class="item" id="item-1">
    <h1>Item 1</h1>
    <a href="#" class="save">Save</a>
  </div>
  <div class="item" id="item-2">
    <h1>Item 2</h1>
    <a href="#" class="save">Save</a>
  </div>
</div>

document.observe("dom:loaded", function() {
  var item = $("item-1");
  var data = item.retrieve("data", {});
  data.url = "http://cowboys.from.hell/items/1";			
 
  $("items").select("a.save").invoke("observe", "click", function(event) {
    alert(event.target.up(".item").retrieve("data").url);
  });
});

Just click the first save link and an alert will display the url I previously stored inside the first item element.

Given what I’m seeing I’m pretty excited about the upcoming version of prototype.

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Terror the micro aggregator

Andrea Franz — Tue, 17 Mar 2009 15:55:54 +0000

Terror is a micro feed aggregator made with sinatra and bundled as a gem. It’s very simple to use, just install the gem:

gem sources -a http://gems.github.com
sudo gem install pilu-terror

Create a new project

terror new_aggregator_name
cd new_aggregator_name

Start the server

thin start -C config/thin.yml

Run the feeds fetcher

rake feeds:fetch # run it as a cron job

You can browse the source and fork it on github.

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