Excellent points, Ian -- thanks. The XUL framework uses the IAccessible2 API, developed by Mozilla and IBM, and reflected in apps such as Firefox and Thunderbird. It is certainly intended to be cross-platform though by means of custom widgets that implement IA2, rather than native widgets of the platform. XUL apps can provide good accessibility on Windows and Linux, though not on the Mac, unfortunately, because Apple has not supported IA2.
Jamal On 6/13/2010 11:22 AM, Ian Sharpe wrote:
Hi Jamal I'm afraid I'm not sure on how accessible this is on the various platforms but XUL provides the GUI for Mozilla (and guess this includes Firefox?). When I looked at this way back now, it looked like a cross-platform XML based UI technology but never had enough time to investigate it properly. I certainly found Mozilla very accessible on Windows using custom colour schemes and screen magnification but suspect it was also accessible for screen reader users since I believe this browser was used by many blind people. I could be wrong but I got the impression XUL utilized the native capabilities of whichever platform the app was running on in much the way you describe. The other point I'd make is that just because your talking about a desktop scenario, there's no reason why you still can't use HTML to produce the UI which can be extremely accessible on all platforms if designed well and appropriate markup used. If I were asked to produce a cross platform accessible desktop app now, I'd probably use this approach but that maybe simply because it's because I very familiar with designing accessible web applications and wouldn't have to worry about platform specific implementations of native widgets as you say. Cheers Ian -----Original Message----- From: program-l-bounce@xxxxxxxxxxxxx [mailto:program-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jamal Mazrui Sent: 12 June 2010 15:57 To: programmingblind; program-l@xxxxxxxxxxxxx Subject: [program-l] Developing cross-platform, accessible apps This is to share some points I have learned about developing cross-platform, GUI-accessible, desktop apps. Currently, the key is using programming libraries that wrap native widgets of the platform. These native widgets generally implement the main accessibility API of the platform, much more so than custom widgets. On Windows, native widgets are most likely to implement Microsoft Active Accessibility, or increasingly, User Interface Automation as it replaces MSAA. On Linux, the GTK+ widgets that are native to the Gnome desktop implement the Assistive Technology Service Provider Interface. On the Mac, Cocoa-based widgets implement the Mac Accessibility Protocol. Thus, a cross-platform library is most likely to create accessible GUIs if it wraps native widgets of each platform, rather than defining its own widgets. A disadvantage of this approach is that the developer needs to be conscious of small differences in the behavior of widgets across platforms, even though wrapping code of the library tries to minimize such differences. Besides accessibility, an advantage of this approach is that widgets have the look and feel that sighted users are accustomed to experiencing on each platform. Sometimes, a GUI library is closely associated with a programming language that has especially strong support for that library in wrapper functions and design tools. A few language and library combinations that seem to work particularly well for cross-platform, accessible development are as follows: * Java and the Standard Widget Toolkit http://www.eclipse.org/swt/ * Python and wxWidgets http://wxPython.org * C# and the System.Windows.Forms classes of the Mono Framework http://mono-project.org Note that, in this case, the Microsoft .NET Framework should be used as the runtime environment on Windows in order to have native widget support. http://msdn.microsoft.com/en-us/netframework/default.aspx If others have further info or ideas on this topic, please share. Jamal ** To leave the list, click on the immediately-following link:- ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=unsubscribe] ** If this link doesn't work then send a message to: ** program-l-request@xxxxxxxxxxxxx ** and in the Subject line type ** unsubscribe ** For other list commands such as vacation mode, click on the ** immediately-following link:- ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=faq] ** or send a message, to ** program-l-request@xxxxxxxxxxxxx with the Subject:- faq ** To leave the list, click on the immediately-following link:- ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=unsubscribe] ** If this link doesn't work then send a message to: ** program-l-request@xxxxxxxxxxxxx ** and in the Subject line type ** unsubscribe ** For other list commands such as vacation mode, click on the ** immediately-following link:- ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=faq] ** or send a message, to ** program-l-request@xxxxxxxxxxxxx with the Subject:- faq
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