New Widget Collection

I have uploaded a modest collection of widgets that I have found useful to GitHub at It includes four widgets: LEDWidget, IPAddressWidget, VerticalLabel, and NeedleGauge. Please feel free to use them as you see fit.

All constructive feedback is welcome, click Like even!


Solved Problem with SVN in Qt Creator

My Qt Creator installation on Windows 10 was having trouble with managing Subversion revisions.  Creator was complaining it couldn’t find svnversion.exe, but other things had to be wrong, as it was unable to add/delete/rename SVN repo files properly.  I figured the problem may be that Creator is a 32-bit application, and was unable to use SVN DLLs.   I re-installed (TortoiseSVN), but since my OS is 64-bit, I had to install the 64-bit version.  Then I noticed this on the download page:

Context menu in file-open/save dialogs on x64 OS

On x64 versions of Windows 7 and 8, the TortoiseSVN context menu and overlays won’t show for 32-bit applications in their file-open/save dialogs until you install the 2017 C-runtime for x86. (select the vc_redist.x86.exe file for download).

Note: this only applies to 32-bit applications on x64 OS. The Windows explorer is not affected by this.

So, I install the vc_redist.x86.exe and everything now works.

Resolving a Problem with Qt Charts in Qt Creator (procedure missing)

I’ve been working a project that uses Qt Charts, which is of course a great library.  I created a custom widget that incorporates a QChartView.  I then decided to create a designer plugin for my new widget.  Unfortunately, after I installed in plugins/designer under Qt Creator’s bin directory, it failed to load, stating “The specified procedure could not be found.”  Given the fact that Creator can’t or won’t show you what procedure is missing, I had to do a little debugging.  I determined that the Qt Charts DLL wasn’t being found.

The solution was to copy the Qt5Charts*.dll files to the Qt Creator bin directory with Qt5Core, etc.  Since Qt Creator is compiled with Visual Studio C++ (in my case MSVC 2015 32-bit), make sure you are copying from the correct bin directory in your installed Qt hierarchy.

This was Qt Creator 4.5.0, Based on Qt 5.10.0 (MSVC 2015, 32 bit)

A Simple Qt Diagram Layout Example

I have uploaded code for a simple Qt application that demonstrates how to make a simple layout using the library libavoid (written and maintained by Michael Wybrow, a member of MArVL: the Monash Adaptive Visualisation Lab at Monash University, Australia), which is part of the Adaptagram project.  The code can be found here on Github.  Libavoid provides fast connector routing around obstacles in a diagram. The application allows you to drag the boxes about the screen; the connecting lines are automatically routed by libavoid. The example was written on Windows 7, against Qt 5.7, using MinGW 5.3. The libavoid source is included in the repository.

Screen Shot 08-22-16 at 10.54 PM

New Article on C++ Design for an ImageBlock Class


I just published a new article under Articles->Miscellaneous->Design of a C++ Data Class for Images. I write about a class I designed some years ago that I used in an image acquisition and processing framework.  I remembered the class fondly, and decided to revisit it and share a little of the process I went through to design it.  Why do you care? Beats me!