category_name=articles%2Fhowto
HOWTO: Answer the question “Is {some site} up or down?”
June 28, 2009 | Comments Off
I just stumbled on a very cool service that helps you answer the question “Is {some site} up or down?” It couldn’t be simpler. Visit http://downforeveryoneorjustme.com and you will see a very simple form that looks like this:
Enter the name of a site and the folks running the site will go check and see if it is possible to visit the site from their location on the net. If the site is reachable you will see something like this:
If it is not reachable you will see something like this:
Setting up Unit Testing in Xcode 3.1
July 28, 2008 | 2 Comments
Xcode includes OCUnit, so you don’t need to get a copy. But, you might want to take a look at their website (http://sente.epfl.ch/software/ocunit/) for information and tutorials on how OCUnit is intended to be used.
If you are planning on doing Test Driven Development (TDD) you may also want to get the following packages:
- OCMock – OCMock is an Objective-C implementation of mock objects. (http://www.mulle-kybernetik.com/software/OCMock/)
- Hamcrest – library of matchers for building test expressions (http://code.google.com/p/hamcrest/)
Other good articles on Xcode Unit Testing that I came across:
- Unit Testing with OCUnit – http://www.macdevcenter.com/pub/a/mac/2004/04/23/ocunit.html?page=1
- Test Driving Your Code with OCUnit – http://developer.apple.com/tools/unittest.html
- Xcode unit testing articles – http://chanson.livejournal.com/tag/unit+testing
- Unit Testing with Xcode – http://www.stiefels.net/2007/05/01/unit-testing-with-xcode/
By reading through the documents references above I was able to get OCUnit up and running for one of my projects. It took a bit of experimentation, but in the end it looks like OCUnit will work just fine for doing TDD in Xcode with Objective-C. Anyone wanting to try out TDD should give it a try. The benefits for your project are significant. Go for it!
Use QImage to create a composite image (i.e. One image with another overlaid on top of it.)
March 19, 2008 | Comments Off
Today I wanted to combine two images of similar size to create a new image. The new image was going to be used for a toolbar button. I have purchased a set of commercial images in the PNG format for use on application toolbars. The set came with a bunch of overlay images that could be used to modify each of the base images. The overlays included things like arrows, warning signs, arrows, people, etc. My first though for using these images was to fire up Adobe Illustrator and just create a new icon by merging the base and overlay together. Then I realized that Qt could do the job for me at runtime, and with a little work I could dynamically overlay different badges on a base icon.
The code below can be used to construct a composite image. You pass in references to a base image and an overlay image. These images are used to construct a third image, and that is returned to the caller.
QImage createImageWithOverlay(const QImage& baseImage, const QImage& overlayImage)
{
QImage imageWithOverlay = QImage(baseImage.size(), QImage::Format_ARGB32_Premultiplied);
QPainter painter(&imageWithOverlay);
painter.setCompositionMode(QPainter::CompositionMode_Source);
painter.fillRect(imageWithOverlay.rect(), Qt::transparent);
painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
painter.drawImage(0, 0, baseImage);
painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
painter.drawImage(0, 0, overlayImage);
painter.end();
return imageWithOverlay;
}
Here is an example of using this routine to create an image that might be used to represent something being transfered from a network attached machine.
QImage baseImage(":/Resources/connect_pc_64.png");
QImage overlayLogoff(":/Resources/overlay_arrow_east_64.png");
QImage logoffImage = createImageWithOverlay(baseImage, overlayLogoff)
The two source images and resulting composite are shown below.
- :/Resources/connect_pc_64.png
- :/Resources/overlay_arrow_east_64.png
- Generated Composite Image
HOWTO – Use Visual Studio 2005 for Qt Open Source Development
February 14, 2006 | Comments Off
THIS IS A WORK IN PROGRESS. EXPECT UPDATES AND DON’T BE SURPRISED BY INCOMPLETE INFORMATION
Trolltech has released Qt 4 under a dual-license for all supported platforms. In earlier versions of Qt they only released the open source version for Mac and Linux, leaving Windows developers with no choice but to purchase a commercial license. That all changed with the release of Qt 4 when Trolltech started to provide an open source version for Windows development too! The only catch was that Trolltech only supports the MinGW GCC compiler for development using the open source version.
This article describes how to patch Qt 4 open source edition on Windows so you can develop using Visual Studio 2005. You can even develop using the free Express edition of Visual Studio 2005 so long as you also install the latest Platform SDK.
Please keep in mind that these patches and tips are not provided so you can get around the very generous Trolltech dual-license terms of use. If you are developing or intend to develop a commercial application using Qt 4 you must purchase a commercial license for Qt 4. Only use the information provided in this article if you wish to develop open source GPL software for the Windows platform and wish to use the Microsoft Visual C++ 2005 compiler instead of the MinGW GCC compiler.
Download Qt 4.1 Source Code, Patches, and Notes
- Download the latest open source Windows version of Qt 4.1 from Trolltech at http://www.trolltech.com/download/qt/windows.html. Unzip the file to C:\. It will extract all of the files into a sub-directory called qt-win-opensource-src-4.1.0.
- Download the latest patch file used to modify the open source version of Qt 4.1 to support Microsoft Visual Studio 2005 from Source Forge at http://sourceforge.net/projects/qtwin/. Unzip the file to C:\qt-win-opensource-src-4.1.0.
- Download the build script, environment setup and notes from http://www.idevelopsoftware.com/downloads/qt/Qt41WinBuildScript.zip. Unzip the file to C:\qt-win-opensource-src-4.1.0.
- If you don’t already have Visual Studio 2005 you can download the Express edition. You will also need to download the Platform SDK.
http://msdn.microsoft.com/vstudio/express/visualC/default.aspx
http://msdn.microsoft.com/vstudio/express/visualc/usingpsdk/default.aspx
Building Qt 4.1 using Visual C++ 2005
Open C:\qt-win-opensource-src-4.1.0 in Windows Explorer.
Double-click on the “Qt 4.1 Command Prompt” shortcut to open a Command Prompt window with the environment setup for Qt 4.1 development. IMPORTANT: You must already have Visual Studio 2005 installed. You may need to edit setenv.cmd if your copy of Visual Studio 2005 is not in the default location.
Run “installpatch41.bat”
This will patch the Qt 4.1 source code so it builds properly using the Visual C++ 2005 compiler.
Run “build.cmd”
This will build all of the Qt 4.1 libraries, utilities, and sample applications using the Visual C++ 2005 compiler.
To rebuild, if necessary, make sure to first clean up the previous build. Do this by running
nmake distclean
from the C:\qt-win-opensource-src-4.1.0 directory.
External Tools Configuration in Visual Studio 2005
Launch Visual Studio 2005 and select the “External Tools…” item from the Tools menu.
Use the “Add button to define each of the following external tools:
Title ……………….. QMake (Project File Generation Mode)
Command ……………… D:\qt-win-opensource-src-4.1.0\bin\qmake.exe
Arguments ……………. -project -spec win32-msvc2005
Initial directory …….. $(ProjectDir)
Use Output window …….. [X]
Treat output as Unicode .. [ ]
Prompt for arguments ….. [ ]
Close on exit ………… [X]
Title ……………….. QMake (Makefile Generation Mode)
Command ……………… D:\qt-win-opensource-src-4.1.0\bin\qmake.exe
Arguments ……………. -makefile -spec win32-msvc2005
Initial directory …….. $(ProjectDir)
Use Output window …….. [X]
Treat output as Unicode .. [ ]
Prompt for arguments ….. [ ]
Close on exit ………… [X]
Title ……………….. Qt Designer
Command ……………… D:\qt-win-opensource-src-4.1.0\bin\designer.exe
Arguments …………….
Initial directory …….. $(ProjectDir)
Use Output window …….. [ ]
Treat output as Unicode .. [ ]
Prompt for arguments ….. [ ]
Close on exit ………… [ ]
Title ……………….. Qt Assistant
Command ……………… D:\qt-win-opensource-src-4.1.0\bin\assistant.exe
Arguments …………….
Initial directory …….. $(ProjectDir)
Use Output window …….. [ ]
Treat output as Unicode .. [ ]
Prompt for arguments ….. [ ]
Close on exit ………… [ ]
Adding a Qt 4.1 Development Toolbar
Add a new toolbar for Qt 4.1 Development by selecting “Customize…” from the Tools menu. Once the “Customize” dialog appears select the “Toolbars” tab and press “New…” For the toolbar name enter “Qt 4.1 Development” and press “OK”.
Select the “Commands” tab on the “Customize” dialog. Select “Tools” from the “Categories:” list. Scroll down in the “Commands:” list until you see “External Command 7″. Drag commands 7, 8, 9, and 10 onto the new “Qt 4.1 Development” toolbar.
Creating a New Visual Studio 2005 Project
Open the “New Project” dialog by selecting File->New->Project… from the menu. Under “Project types” on the left side of the dialog expand “Visual C++” and then select “General.” The right side of the dialog will display a list of all the general project types. Select “Makefile Project” from the list of project types. Provide a name for the project and set the location on disk where you wish the project to be saved. Be sure not to check “Create directory for solution”, as this will create an extra level of directories that is just confusing. Click the “OK” button and you will be presented with the “Makefile Application Wizard.” Simply press the “Finish” button on the first page of the wizard.
Once the project has been created and opened, set the NMake Configuration Properties for the project as shown below. In the “Solution Explorer” right-click on the name of your project. Select “Properties…” from the context menu. On the property pages dialog select “Configuration Properties” and “NMake” on the left side tree control. On the right side, enter the following information, making sure to set the properties for both the debug and release configurations.
Release Configuration Settings
General
——-
Build Command Line …………………. nmake release-all
Rebuild All Commaond Line …………… nmake release-clean release-all
Clean Command Line …………………. nmake release-clean
Output ……………………………. foo.exe
IntelliSense
————
Common Language Runtime Support ……… No Common Language Runtime support
Preprocessor Definitions ……………. WIN32;NDEBUG;UNICODE;QT_LARGEFILE_SUPPORT;QT_DLL;
QT_GUI_LIB;QT_CORE_LIB;QT_THREAD_SUPPORT
Include Search Path ………………… “c:/qt-win-opensource-src-4.1.0/include/QtCore”;
“c:/qt-win-opensource-src-4.1.0/include/QtGui”;
“c:/qt-win-opensource-src-4.1.0/include”;
“c:/qt-win-opensource-src-4.1.0/include/ActiveQt”;
“c:/qt-win-opensource-src-4.1.0/mkspecs/win32-msvc2005″
Forced Includes …………………….
Assembly Search Path ………………..
Forced Using Assemblies ……………..
Debug Configuration Settings
General
——-
Build Command Line …………………. nmake debug-all
Rebuild All Commaond Line …………… nmake debug-clean debug-all
Clean Command Line …………………. nmake debug-clean
Output ……………………………. food.exe
IntelliSense
————
Common Language Runtime Support ……… No Common Language Runtime support
Preprocessor Definitions ……………. WIN32;_DEBUG;UNICODE;QT_LARGEFILE_SUPPORT;QT_DLL;
QT_GUI_LIB;QT_CORE_LIB;QT_THREAD_SUPPORT
Include Search Path ………………… “c:/qt-win-opensource-src-4.1.0/include/QtCore”;
“c:/qt-win-opensource-src-4.1.0/include/QtGui”;
“c:/qt-win-opensource-src-4.1.0/include”;
“c:/qt-win-opensource-src-4.1.0/include/ActiveQt”;
“c:/qt-win-opensource-src-4.1.0/mkspecs/win32-msvc2005″
Forced Includes …………………….
Assembly Search Path ………………..
Forced Using Assemblies ……………..
QMake Project Settings
Create a project file called “foo.pro” in the directory for your makefile project. Replace the name “foo.pro” with the name of your actual application. Place the file in the directory where your Visual Studio project was created. To start with, the contents might look something like this:
CONFIG += qt
TEMPLATE = app
SOURCES += foo.cpp
HEADERS += foo.h
FORMS += foo.ui
You should be off and running now. For more detailed information I would suggest reading the qmake reference manual. You might also want to take a look at the Qt 4.1 tutorials in Qt Assistant. Have fun!
