asp.net barcode generator Working with Different Platforms in Font

Printing Data Matrix ECC200 in Font Working with Different Platforms

There are many reasons why you might want to be able to handle platform specifics when using a platform-neutral toolkit such as Qt. For example, you might want to use different icons on different platforms or have a piece of custom source code that is platform-dependent. QMake makes it easy to build your project in slightly different ways, depending on the platform being used. The different platforms are handled using a concept called scopes. There are lots of scopes supported by Qt, but the most common are these: debug: The project is being built in debug mode. release: The project is being built in release mode. win32: The project is being built in a Windows environment. macx: The project is being built in a Mac OS X environment. unix (including Linux): The project is being built in a Unix environment. You can handle scopes in two different ways. You can use brackets, as shown in the library choosing if-else structure here: win32 { LIBS += -lmywin32lib } else macx { LIBS += -lmymacxlib } else { LIBS += -lmyunixlib } You can combine scopes by using the : operator; for example, macx:debug: ... is equivalent to writing macx { debug { ... } }. The : operator brings an alternate way of specifying scopes. You can set the LIBS variable like this: win32:LIBS += -lmywin32lib macx:LIBS += -lmymacxlib !win32:!macx:LIBS += -lmyunixlib

Notice that the ! operator was used to invert the scope. The expression !win32:!macx means not win32 nor macx.

If you want to be able to show debug output, you can add the value console to the CONFIG variable. A more delicate way of doing this is to limit the change to Windows and debug mode applications: win32:debug:CONFIG += console It ensures that you do not open a console window for applications built in release mode. Another issue that you need to take care of when building applications for the Windows platform is the application icon (the icon that Explorer uses when showing the executable).

The application icon on Windows is represented by a Windows resource (not to be confused with Qt resources), so you have to create a Windows resource file and add it to the Qt project file. First you need to create an icon with the ico file format. There are many tools for creating these files (examples include the Gimp and the icon editor in Visual Studio, but searching the Internet shows numerous alternatives). After you create an icon, you need to create the Windows resource file, which is a file with the file extension rc. The file should consist of the following line. IDI_ICON1 ICON DISCARDABLE "filename.ico" Replace filename.ico with your icon. To add the resource file to your project file, simply add a line reading RC_FILE += filename.rc, where filename.rc is your Windows resource file. There is no need to prefix this line with a win32 scope because it is ignored on the platforms where it does not apply.

The biggest difference between Mac OS X and the other platforms supported by Qt is the ability to run the same application on several processor platforms. The processors available, PowerPC and Intel x86, have many differences most troublesome is the endianess. Make sure to always use Qt streams to load and store data not only to files but also to databases, network streams, and other buffers that can be read and written by both processors. The problem exists in the order of the bytes in multibyte values. For instance, a 32-bit integer reading 0x12345678 on one of the platforms will be read as 0x78563412 on the other if you do not decide which endianess to stick to. When configuring Qt on the Mac OS X platform, you can use the -universal flag, which makes it possible to create universal binaries. You control which processors to support using the CONFIG variable and the ppc and x86 values. Typing CONFIG += x86 ppc creates a universal project that can be executed on either platform.