QTextDocument, HTML, and Unicode: It’s All Greek To Me

To generate reports in my Qt-based software, I create a QTextDocument, which may contain some Unicode characters, convert it to HTML, and then save it to a file.

But the Unicode characters were not being being displayed properly when I opened it in a browser:

Unicode Not Displayed Properly

Unicode Not Displayed Properly

Taking a look at the generated HTML, I noticed that the content encoding was not being set:

So I thought I could simply specify the encoding in the call to toHtml() which would set the encoding in the HTML header.

That looks better! But wait…

Unicode Still Not Displayed Properly

Unicode Still Not Displayed Properly

Uhhh… That looks worse.

After scouring the interwebs, I eventually found the answer. The QTextStream encodes based on the system locale so if you don’t set it explicitly you might not get what you expect. According to the QTextStream docs:

By default, QTextCodec::codecForLocale() is used, and automatic unicode detection is enabled.

For some reason the automatic detection did not work for my case, but the solution is to set the encoding manually using QTextStream::setCodec() like this:

Aha! Now my Greek looked Greek!

Unicode Displayed Properly

Unicode Displayed Properly

Torque Console Messages and Static Initialization

I figured I’d write this up for the one other person in the world that is going to run into this. Might save someone some time.

Several years ago I used to work at GarageGames on the Torque game engine. I worked on an internal version of the engine that was used for several of our games and by a few third-party games. While this version of the engine was never released, a whole bunch of our work ended up in TGEA at some point. So what I’m describing applies to at least some versions of Torque Game Engine Advanced (TGEA) as well [I have 1.8.2]. It may apply to the current iteration of the Torque engine – Torque 3D – but I don’t have it so I don’t know for sure.

Recently I was reviving a game that was written using an early version of this internal engine. I was updating the FMOD library and ran into a loading problem. While tracking it down, I found myself in sfx/fmod/SFXFMODProvider.cpp where the SFXFMODProvider constructor had a bunch of calls to Con::warnf(), but I wasn’t seeing anything in the console log. The problem was that the console log hadn’t been created yet because the SFXFMODProvider constructor is called during static initialization.

Taking a look at console/console.cpp, Con::printf(), Con::warnf(), and Con::errorf() ultimately call a static function _printf() which starts like this:

Guess that’s why I wasn’t seeing anything – we’re just throwing away all messages if we aren’t active yet!

So the obvious way to fix this is simply to save our messages instead of throwing them away and then to output them when we do become active. Easy as pie.

Now any messages that are sent using Con::printf(), Con::warnf(), or Con::errorf() during static initialization or before the console is active will show up at the top of console.log.

Hope the one guy who finds this useful in the future buys me a beer…

PHP and Default Timezones

Just in case anyone else runs into this I thought I’d record it for Google’s sake…

My business website was down. My web host was being non-helpful – “we’re aware there’s a problem and we’re working on it” – so there was nothing I could do but sleep on it and hope the site would be back up in the morning. When it finally came back online, I was faced with dozens of warnings like this:

Warning: strftime() [function.strftime]: It is not safe to rely on the system’s timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected ‘America/New_York’ for ‘EST/-5.0/no DST’ instead in [file name & line number]

Obviously they’d updated PHP or changed some settings.

Slightly panicked, a quick Google led to a bunch of solutions involving changing php.ini which I do not have access to because the site is on a shared host. I could probably have saved some time by, uh, you know, actually reading the warning.

The solution was to add a call the PHP function date_default_timezone_set() with one of the supported timezones in my config.php:

Oddly enough, the list of supported timezones for America does not include Ottawa, Ontario – the capital of Canada and fourth largest city in the country – but includes the tiny town of Swift Current, Saskatchewan [Pop. 15,000]. Quoi?

In-memory ZIP File Access Using Qt

A while ago I was working on a little tool to manage my media files – TV shows and movies that I’d ripped from my DVD collection that I wanted to make available through XBMC on my home theater system. To display things like plot, characters, runtime, etc., XBMC reads NFO files – which are just XML files – one for each media file. Entering this information by hand is not a fun afternoon activity, so I looked for a way to automate it. I found a couple of different sites that provided the data I needed via APIs and eventually settled on TheTVDB.com for TV series and themoviedb.org for movies. So all I needed to do was read the data using the APIs and write it to the NFO files. Simple!

For each TV series, TheTVDB provides a ZIP file containing several XML files which splits up the information to make it more manageable and allows for easier internationalization. A typical ZIP from TheTVDB contains files such as actors.xml, banners.xml, and en.xml. The actors.xml file contains a list of actors, the roles they play, a link to an image, etc.. banners.xml provides links to fan art and thumbnails which XBMC can use for display. en.xml provides the core data: a description of the TV series and a list of all the episodes from the series including plot, runtime, air date, etc. for each of them.

So what’s the best way to download and access this zipped data? Continue reading

QString::toStdString, QString::fromStdString, and -no-stl

I use the Qt library in my day-to-day development work. I build my Qt libraries directly from the git repository and they are configured specifically for my projects. On the Mac OS X side, this is the command line I use:

The Windows one is similar:

You will notice that I am explicitly removing a whole bunch of stuff – SVG, WebKit, audio, etc.. The time it takes to build the Qt libraries is not insignificant and since I typically track the git repo, I don’t want to waste time building things I will not be using in my projects. The WebKit code takes an extraordinary amount of time to build, for example. I also don’t want to build things into the libs that I’m not going to be using for my commercial software – such as STL. One of the problems this poses, however, is how to handle build problems with other projects I want to build, for example the GUI for the open-source Cppcheck program.

For the most part the projects I’m interested in don’t use any of the capabilities I’m eliminating from my Qt build, but one option has been problematic for a couple of projects: -no-stl. This is because the projects use the functions QString::toStdString() and QString::fromStdString() which do not exist when you build Qt with the -no-stl option. While STL may be available to the source you are building, it was not compiled into the Qt libs, so this causes an error.

When I try to build Cppcheck using my own Qt build, I get errors like this:

../gui/mainwindow.cpp: In member function ‘Settings MainWindow::GetCppcheckSettings()’: ../gui/mainwindow.cpp:457: error: ‘class QString’ has no member named ‘toStdString’

../gui/threadresult.cpp: In member function ‘virtual void ThreadResult::reportOut(const std::string&)’: ../gui/threadresult.cpp:42: error: ‘fromStdString’ is not a member of ‘QString’

Solutions?

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COLLADA Files and SketchUp Component Hierarchies

One of the formats my bloodstain pattern analysis software will export data to is COLLADA. COLLADA is an open format used to exchange 3D scene data between software packages. It is an XML format, meaning it’s readable in a text editor, but it is extremely verbose and not a simple thing to understand unless you know what you’re looking at [and even then…]. Before using it for my current work, I’d used COLLADA with an internal version of the Torque game engine at GarageGames, so I had some familiarity with the format before using it this time.

SketchUp is a powerful free modelling tool from Google. As with any software importing COLLADA, some of the concepts in the format map to concepts within the software, while others do not. One of the things that was not obvious to me when I started exporting COLLADA files for use in Google SketchUp was how to set up my COLLADA so it had hierarchical components upon import. My scenes always showed up as one monolithic component which meant that modifying parts of it to add textures or colours was not easy.

For the bloodstain analysis work, I only have to deal with simple scenes consisting of planar surfaces and lines.

SketchUp COLLADA Import Example

SketchUp COLLADA Import Example

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Cppcheck

Cppcheck is an open source cool tool by Daniel Marjamäki used to statically analyse C/C++ code for errors, questionable code, and style. I’ve been tracking it for a number of months and, while it is still in active development, it is already a very useful tool. There are command line and GUI versions available for several platforms.

The Cppcheck wiki page gives a lot more information about it, and lists a couple of hundred checks that are performed on your code.

A git repository is available which makes it easy to keep up-to-date with the latest developments. The source also includes a Qt-based GUI which is quite straightforward to compile using Qt Creator. The GUI is functional, but could use a little bit of work to make it more friendly. In order to view error or warning in the source, for example, Cppcheck requires an external program. It really ought to show you the code in context in the main window, allowing you to correct things within the application.

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