Using dynamic libraries in Mac OS X

I downloaded and built the excellent Qwt widget collection on my Mac. When I built the examples I had trouble getting them to find the libqwt dynamic library. They built and linked just fine, but unless I added the path to the qwt install dir to my DYLD_LIBRARY_PATH environment variable launching the application fails with a dyld: Library not loaded: libqwt.5.dylib error.

On Linux the solution would be to add a -Wl -rpath /usr/local/qwt-5.0.2/lib to my LIBS directive in my projects’s .pro file (in this case the relevant line is in the examples/examples.pri config file). This should add the path to qwt’s dylib to my application’s runtime search path. Unfortunately this doesn’t work in Mac OS X. As it turns out, the library itself has to know its full install path.

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Graphing with yEd

I used to render UML graphs using the excellent GraphViz—writing out the graphs in dot formatted files by hand as GraphViz doesn’t have any GUI for graph editing. This worked pretty well until I started needing more fine control over the organization and appearance of my graphs. I resorted to ugly dot constructions like

{ rank=same ringbuffer inputproc; }  // put two nodes on the same level

and

buffer_a   [label="buffer"]  // give two nodes the same name
buffer_b   [label="buffer"]

Recently a coworker alerted me to the existence of yEd, an awesome free graphing program written in Java. It creates GraphML-format files using a slick, well-designed interface. It has powerful graph-organizing tools and supports SVG symbols as graph nodes. The graphs look great when printed, too.

WordRecorder 1.0 released

WordRecorder was a program I wrote for my friend Matt to help him record hundreds of spoken names for his video e-card site. It’s a pretty specialized program and I doubt more than a handful of people out there will actually have a need for it, but the source code may be of use to people trying to figure out how to use Apple’s CoreAudio Frameworks and the Qt Interface Toolkit.

I’ll try to post more details about its design and how it works in the coming days. For now, visit the main WordRecorder page here.

Xcode 3 doesn’t like projects generated by qmake

When trying to build a Universal version of my WordRecorder app I discovered that I could not view the properties window for my executable target, the project itself, or the project’s SCM options. Xcode gave me the following lovely error:

XCode: Internal Error

I don’t know what this is about, but through some hacking and tinkering with the Xcode file I came up with the following messy workaround:

  1. Make your Xcode project using qmake -spec macx-xcode if you haven’t already.
  2. Open/reload the resulting project in XCode 3. Trying to edit the project properties will yield the above error.
  3. Save the Project. This step is necessary as it makes Xcode totally reformat the file making the edit we’re about to do much easier.
  4. Open the project’s “project.pbxproj” file in your text editor. It lives inside the “.xcodeproject” folder so you’ll have to do a “Show Package Contents” to see it in the Finder.
  5. Find the following comment (“hello_world” will be the name of your own target) 
    /* Build configuration list for PBXNativeTarget "hello_world" */
  6. Beneath this comment you’ll see the following list of build configurations (the actual IDs will be different): 
    isa = XCConfigurationList;
buildConfigurations = (
2F9BD7250DBC2F9500BBEE4F /* Debug */,
2F9BD7260DBC2F9500BBEE4F /* Release */,
2F9BD7270DBC2F9500BBEE4F /* Default */,
);
  7. Remove the entire line containing the identifier with the name ‘Default’ and save the file. The result will look like this: 
    isa = XCConfigurationList;
buildConfigurations = (
2F9BD7250DBC2F9500BBEE4F /* Debug */,
2F9BD7260DBC2F9500BBEE4F /* Release */,
);
  8. Go back to Xcode. It should prompt you to reload the project from disk. Reload it. You should now be able to edit your project’s properties again. Unfortunately you will have to repeat this step whenever you rebuild your project using qmake.

I don’t know why this fix works, but it beats having to recreate our Xcode project by hand, and everything still seems to build without incident after the fix.

I’m not sure if this is Apple or Trolltech’s problem as I can’t remember if this worked in Qt 4.3.3 / Xcode 2. Xcode 3 probably isn’t officially supported by qmake yet, anyway.

Two-sided printing in OS X

So a while ago I bought an HP 6800 Inkjet Printer with the double sided printing option. It’s great, but the default HP drivers don’t support the double sided printing, so the extra money spent on that hardware is essentially wasted if you use a Mac.

A solution comes from the Open Printing Workgroup at the Linux Foundation. By first installing the ESP Ghostscript and Foomatic RIP packages on their website, you can install the hpijs package—too many names, yes. This gives you the hpijs driver for the Deskjet 6800 (and many other printers) with the double-sided option enabled.

I’ve found the hpijs driver isn’t as crisp as the HP drivers (HP Inkjet 3.3.1), and it’s even failed miserably when I’ve tried to print some more complicated PDF files, but otherwise it’s a great way to save paper when printing things like receipts and news articles where quality isn’t my highest priority.

UPDATE: A recent upgrade of the HP Printer Drivers for OS X has fixed this problem. The specific driver is called “HP Inkjet Version 3.3.3”.

While the standard print dialog still has the “Two Sided:” option grayed-out under the Layout tab, a new “Two-sided Printing” tab has appeared in the dropdown list. This one is enabled and actually seems to work properly.