Th30z - Coding on the Fly » Qt4

PyQt4 Schema Script

Matteo Bertozzi — Sat, 30 Jan 2010 10:12:21 +0000

I’ve received a couple of emails asking me what I use to draw various graphs and schema that I post on this blog. And the obviously answer is QPainter! I’ve a small PyQt script that does the easy things but the more difficult one is coded every time…

The script is really simple, it take an xml input and just draw the few items that can recognize. You can use RGBA colors and you can draw linee-paths, like in the image above. The XML looks like this one:






    I'm just a Test!

I know that it’s a stupid thing and making xml seems to be a long job, but this is what I need at the moment, maybe in the future this script will get a WYSIWYG ui but at this time is just a simple script that generate an image

The source code with the above example is available here: PyQt4 Schema Script.

Qt4 Image Crop Item

Matteo Bertozzi — Sat, 16 Jan 2010 13:29:49 +0000

Just a quick break from Math, File-System and Data Structure (I’m overly busy). The example below is a simple QGraphicsItem, that allow the user to select an area on the screen, like the “crop tool” that you can see in every Image Editor. The source code is very simple, just paint() and moveEvent() handlers.

The source code is available here: Qt4 Image Crop Item Source Code.

Qt4/OpenGL: Pose Editor

Matteo Bertozzi — Sun, 13 Dec 2009 08:57:08 +0000

Last week I’ve published an automated “Puppet Animation” to show how Skeletal Animation and OpenGL works. Today, I’ve made something more to help you in the Animation Design Process.

The Qt code is really simple, it was just an UI with some slider connected to the Model Bones Matrix to performs Rotations and Translations and a QGLWidget that displays the OpenGL that you’ve already seen in the last post. I’ve also added a Useful ListWidget to display textures that are loaded by the model.

To get some cool models you can start by checking Blender’s Open Projects that allows you to download models from Elephants Dream (see the screenshot above), Big Buck Bunny or Yo Frankie!. I’m still working on a better way to export Bones from Blender, If you’ve already tried and want to share some information, give me a mail! (thanks).

For this example, I’ve made a Big Package that contains the OpenGL engine that allows you to load and drows models and the Qt4 Pose Editor Tool that you can easily find in tools/ folder. The Source code is available here: Qt4/OpenGL Pose Editor Source Code.

Qt4 Imap API

Matteo Bertozzi — Sat, 01 Aug 2009 05:39:07 +0000

Pushed in my GitHub repo the first draft of the Qt4 Imap (RFC 3501 Interne Message Access Protocol) Library.
I’ve implemented a sync communication because it’s much easier to use, so if you want to use it in async way you need to implement a thread class that wrap the Imap class and throws the events that you need.


Imap imap;
if (!imap.connectToHost(IMAP_HOST, IMAP_PORT, IMAP_USE_SSL))
   IMAP_MAIN_ABORT("connectToHost()", imap.errorString());

if (!imap.login(IMAP_USERNAME, IMAP_PASSWORD, IMAP_LOGIN_TYPE))
   IMAP_MAIN_ABORT("login()", imap.errorString());

ImapMailbox *mailbox = imap.select("INBOX");
qDebug() << "INBOX";
qDebug() << " - Exists:" << mailbox->exists();
qDebug() << " - Unseen:" << mailbox->unseen();

QList messageList = imap.searchRecentUnseen();
imap.fetch(mailbox, messageList);
foreach (int msgId, messageList) {
   ImapMessage *message = mailbox->findById(msgId);
   if (message == NULL) continue;

   imap.fetchBodyStructure(message);

   qDebug() << "FROM" << message->fromAddress().toString();
   foreach (ImapAddress address, message->toAddresses())
      qDebug() << " - TO" << address.toString();
   qDebug() << "SUBJECT" << message->subject();

   for (int i = 0; i < message->bodyPartCount(); ++i) {
      ImapMessageBodyPart *bodyPart = message->bodyPartAt(i);
      imap.fetchBodyPart(message, i);

      qDebug() << bodyPart->isAttachment() << bodyPart->contentType();
      qDebug() << bodyPart->data();
   }
}

delete mailbox;

imap.logout();
imap.disconnectFromHost();

Qt4 Google Contacts APIs

Matteo Bertozzi — Fri, 24 Jul 2009 05:53:54 +0000

Just pushed at GitHub the first draft of the Qt4 Google Contacts Service…

Contacts APIs allows client applications to view and update Contacts content in the form of Google Data API feeds. Your client application can request a list of a user’s contacts, edit or delete content in an existing contact.


// Setup Contact
THGoogleContact *contact = new THGoogleContact;
contact->setFullName("John Doe");

THGoogleIm *im = new THGoogleIm;
im->setRel(THGoogleIm::relWork());
im->setAddress("john.doe@aim.com");
im->setProtocol(THGoogleIm::protocolAim());
contact->addImAddress(im);

THGoogleEmail *email = new THGoogleEmail;
email->setAddress("john.doe@mail.com");
email->setRel(THGoogleEmail::relWork());
contact->addEmailAddress(email);

// Insert Contact
THGoogleContactsService *gContacts = new THGoogleContactsService;
gContacts->setAuthToken(...);
gContacts->insertContact(contact);

Take a look at contacttest.cpp for a more complete usage example.

Qt4 Google MapView

Matteo Bertozzi — Sun, 12 Jul 2009 09:07:07 +0000

I’ve received a couple of requests about Google Maps and Qt4. Today I’ve written a simple Widget that allows you to interact with Google Maps and Google Geocoder. You can set Map Type (Roadmap, Satellite, Terrain and Hybrid), you can set your center Coordinate, add Markers, add Info Windows get the User Click Coordinates and other things that Google Maps allows to do.

With few lines of code, you can interact with Google Maps, and below you can see how to do it. (Other methods and overloads are available, check the GKMapView.h in the Source Code packet, link is at the end of the post).


GKMapView mapView;

// Change the Default MapType (Roadmap, Satellite, Terrain, Hybrid)
mapView.setMapType(GKMapTypeSatellite);

// Use Geocoder to Get Location from Address or Viceversa.
// See the Signals locationFound, locationNotFound() and
// addressFound(), addressNotFound() to get your results.
mapView.locationFromAddress("San Mateo");
mapView.addressFromLocation(32.718834, -117.164);

// Add Marker With Info Window at Specified Address (or Location)
mapView.addMarkerWithWindow("Bedford MA Marker",
                            "Bedford MA Marker",
                            "Bedford MA");

// Add Info Window without Marker using Address or Coordinates
mapView.addInfoWindow("Hello from San Mateo", "San Mateo");
mapView.addInfoWindow("Hello from San Diego", 32.718834, -117.164);

// Change your Current Location
mapView.setLocation("Phoenix AZ");

The Source Code is available Here with a small example: Qt4 Google Map View Source Code.

Qt4 Canvas Plugins

Matteo Bertozzi — Sun, 28 Jun 2009 10:52:46 +0000

Today, during my Sunday morning bike trip I’ve had an Idea on how to simply implement a Canvas Plugins in Qt Applications, to give you an idea of How browser external plugins like flash or others works. The Code is really simple there’s a class CanvasPlugin with a couple of Abstract Methods Init, UnInit, Resize, MouseEvent and a signal that says “Hey, Paint this Image!”. To give you an Idea of the result below you can see a Window with two Widgets, a CanvasPluginViewer and a Label. Canvas Plugin Viewer load an external Library (.so) passed to the command line as first argument.

You can interact with the canvas like a normal widget (the red square moves along the window and you can stop and resume its animation). But you can extend the sample sending and receiving information from a server, or you can do other crazy external things. (See flash usage for more ideas).

That’s all folks, it’s lunch time. If you’ve any question send me a mail or write a comment, and remember that this is just a couple of minutes coded example, so don’t use in your highly stable app.

The Source Code is Available Here: Qt4 Canvas Plugins Source Code.

Qt4 iPhone Like Cut/Copy/Paste Widget

Matteo Bertozzi — Sat, 13 Jun 2009 17:36:55 +0000

I’m watching the WWDC Keynote podcast, Just finished the Bertrand Serlet Talk, about Snow Leopard. Now before watching Scott Forstall with the new iPhone 3GS, a little break with an example of Cut, Copy and Paste like Widget. (In the Snow Leopard dock demo, I’ve seen “the same” widget used to do expose)

It’s a really simple example but it can be useful to someone to understand how to add actions to a custom shape.

The Source Code is available Here: Qt4 iPhone Like Cut, Copy Paste Source Code.

Qt4 Geo IP Location

Matteo Bertozzi — Fri, 12 Jun 2009 05:52:57 +0000

In a time of Google Maps, Geo Location and other services like this… Here an example of Geo IP Location Service (http://www.hostip.info/) is really far from perfect, but it’s just an example.

The sample uses QNetworkAccessManager to get the Geo Location of the IP, and Webkit to display the address on the Google Map.

The Source Code is available Here: Qt4 Geo IP Location Source Code.

Qt4 Google Services: Translator, Spell Checker and more…

Matteo Bertozzi — Sat, 06 Jun 2009 07:31:16 +0000

Last month I’ve made a simple wrapper for Google Authentication, Today I’ve written other 4 classes to wrap the Google’s Translator, Language Detector, Suggestions and the Spell Checker Services.

Translator Example


QEventLoop l;
THGoogleTranslator gTranslator;
connect(&gTranslator, SIGNAL(finished(bool)), &l, SLOT(quit()));
gTranslator.setDestinationLanguage("en");
gTranslator.translate("Ciao");
l.exec();

qDebug() << gTranslator.translatedText(); // Maybe "Hello"
qDebug() << gTranslator.detectedSourceLanguage(); // Maybe "it"

Suggest Example


QEventLoop l;
THGoogleSuggest gSuggest;
connect(&gSuggest, SIGNAL(finished(bool)), &l, SLOT(quit()));
gSuggest.suggest("Qt Softw");
l.exec();

qDebug() << gSuggest.suggestions();
// ("qt software", "qt software download", "qt software gpl exception", ...)

Spell Checker Example


QEventLoop l;
THGoogleSpellChecker gSpellChecker;
connect(&gSpellChecker, SIGNAL(finished(bool)), &l, SLOT(quit()));
gSpellChecker.spellCheck("Gogl Spll");
l.exec();

// "Gogl" ("Google", "Gogol", "Gog", "Goal", "Gog's")
// "Spll" ("Spell", "Sp ll", "Sp-ll", "Spill", "Sell")
foreach (QString original, gSpellChecker.keys())
    qDebug() << original << gSpellChecker.suggestions(original);

Language Detector Example


QEventLoop l;
THGoogleDetectLanguage gDetectLang;
connect(&gDetectLang, SIGNAL(finished(bool)), &l, SLOT(quit()));
gDetectLang.detectLanguage("Ciao");
l.exec();

qDebug() << "Query" << gDetectLang.query();
qDebug() << "Language" << gDetectLang.language(); // Maybe "it"
qDebug() << "Is Reliable" << gDetectLang.isReliable();
qDebug() << "Confidence" << gDetectLang.confidence();

You can find the source at GitHub (Git WebView) or you can download the source code Here: Qt4 Google Services Take 2 Source Code.

Qt4 Jump Away Animation

Matteo Bertozzi — Sat, 16 May 2009 16:24:53 +0000

When I’ve started working on Mac OS X with Core Animation, I was impressed by an Example (I don’t remember the link, if someone knows it, post it in the comments! thanks)… Very few lines of code for a great effect.

After a year, or probably more.. this example was came back to my mind, so I’ve decided to clone using Qt. And below you can see a short Demonstration Video. Your desktop jump away.. full screen is fantastic

The Source Code is Available Here: Qt4 Jump Away Animation Source Code.

PyQt4: PyCon3 Photos on Flickr

Matteo Bertozzi — Sat, 16 May 2009 05:44:19 +0000

PyCon3 was finished, Only one week is passed and I already miss it. Guido van Rossum, Alex Martelli, Ariya Hidayat, Raymond Hettinger, David Boddie, Fredrik Lundh… C/C++ and Python Developer not .NET “coders” (I hate even more my boring .NET job).

Following the PyCon week, here a simple example of PyQt4 that allows you to see up to 500 photos tagged PyCon3 on Flickr.

As always the source code is available here: PyQt4 PyCon3 Flickr Source Code.

Qt4 Touch and Rotate

Matteo Bertozzi — Thu, 07 May 2009 04:27:01 +0000

Alan has asked my How I’ve implemented the Touch and Rotate feature of the Moko. The answer is very simple, It’s all Magic! There’re very few lines of code to do it, because all the magic is made by atan2.

Atan2 is a variation of the arctangent function. For any real arguments x and y not both equal to zero, atan2(y, x) is the angle in radians between the positive x-axis of a plane and the point given by the coordinates (x, y) on it.

The Source Code is available here: Qt4 Touch and Rotate Source Code.

OT: PyCon3 (Italia) starts Tomorrow!

Qt4 JSON Stream Reader

Matteo Bertozzi — Sat, 02 May 2009 09:00:43 +0000

JSON, short for JavaScript Object Notation, is a lightweight computer data interchange format. It is a text-based, human-readable format for representing simple data structures and associative arrays (called objects).

One way to use JSON with Qt4 is using the QScriptEngine (engine.Evaluate(jsonSource)), But I like Reinventing the wheel, so I’ve written a simple JSON Stream Reader that works “almost” like the QXmlStreamReader.

You’ve a readNext() method that read the next token and returns its type, and two properties name() and values() that Returns the name of the Property, Object or Array and the Value of the Property in a QVariant that can be Bool, Int, Double or String.

Below there’s an Example of How to use the JSON Stream Reader. Maybe you can use it to create an automatic Object Mapper like the Xml Object Mapper that I’ve posted a couple of weeks ago.


QFile file("test.json");
if (!file.open(QIODevice::ReadOnly)) {
   qDebug() << file.errorString();
   return(1);
}

THJsonStreamReader reader(&file);
while (!reader.atEnd()) {
   switch (reader.readNext()) {
      case THJsonStreamReader::PropertyNumerical:
         qDebug() << " - Property Numerical" << reader.name() << reader.value();
         break;
      case THJsonStreamReader::PropertyString:
         qDebug() << " - Property String" << reader.name() << reader.value();
         break;
      case THJsonStreamReader::PropertyFalse:
         qDebug() << " - Property False" << reader.name() << reader.value();
         break;
      case THJsonStreamReader::PropertyTrue:
         qDebug() << " - Property True" << reader.name() << reader.value();
         break;
      case THJsonStreamReader::PropertyNull:
         qDebug() << " - Property Null" << reader.name();
         break;
      case THJsonStreamReader::Object:
         qDebug() << "Object" << reader.name();
         break;
      case THJsonStreamReader::ObjectEnd:
         qDebug() << "Object End";
         break;
      case THJsonStreamReader::Array:
         qDebug() << "Array" << reader.name();
         break;
      case THJsonStreamReader::ArrayEnd:
         qDebug() << "Array End";
         break;
   }
}

file.close();

The Source Code is Available Here: Qt4 JSON Stream Reader Source Code.

Qt4 Google Authentication

Matteo Bertozzi — Fri, 01 May 2009 11:53:11 +0000

Today, I’m looking at Google services, Contacts, Maps, Search… to use all this service in your app you need to get The Authentication Token (see the Google Auth For Installed Apps page). So, I’ve implemented a simple class to do this.


QEventLoop q;
THGoogleAuth gAuth("MYNAME@gmail.com");
QObject::connect(&gAuth, SIGNAL(authenticated()), &q, SLOT(quit()));
gAuth.login(THGoogleAuth::Contacts, "MYPASSWORD");
q.exec();

if (gAuth.error() == THGoogleAuth::NoError) {
    qDebug() << "SID" << gAuth.sid();
    qDebug() << "LSID" << gAuth.lsid();
    qDebug() << "AUTH" << gAuth.auth();
} else {
    qDebug() << gAuth.errorString();
}

The Source Code is Available Here: Qt4 Google Auth Source Code.