[jawsscripts] Re: Opinion post: Time to change where new scripters begin
- From: Soronel Haetir <soronel.haetir@xxxxxxxxx>
- To: jawsscripts@xxxxxxxxxxxxx, Doug Lee <doug.lee@xxxxxxxxxxxxxxxx>
- Date: Thu, 27 Feb 2014 06:14:13 -0900
I agree fully with the idea that UIA should be the starting point for
anyone picking up scripting from jaws 15 on. My answer to your point
about UIA being complicated is that programming simply is complicated.
The main reason I would say that UIA should be the starting point is
(and you did mention this) the fact that old style window navigation
simply will not work for lots of new programs because they are not
written using individual windows for each UI element. Visual studio
is a great example of this, it switched to WPF awhile back and so now
only has a single window for the entire main UI (transient child
windows are still created and plugins can still be window based, but
everything that is present in the typical visual studio layout is now
rendered in just one HWND). Such programs are only going to become
more common as time goes on.
On 2/27/14, Doug Lee <doug.lee@xxxxxxxxxxxxxxxx> wrote:
> For years I have complained, as many probably have, that it is hard to
> know how to start off a new JAWS scripter in a way that will empower
> him or her to script the average application without getting
> hopelessly lost or buried in details. A common initial approach has
> been to teach window hierarchy navigation and cursor manipulation, but
> these techniques increasingly fail to be sufficient to fix major
> problems in current applications. This leaves new scripters stuck in
> dead ends wondering where to go next. I believe it is time to change
> where we start them off.
>
> I believe, starting in recent JAWS 15 updates, that we finally have
> one consistent, all-empowering path for scripters to take. There are of
> course caveats, but I'll get to that. This path will give scripters
> access to many things that previously required entire different
> sets of function calls - window tree functions here, MSAA functions
> there, HTML DOM access, etc.
>
> JAWS 15, particularly starting with the 15.0.5056 update, introduces
> direct scripter access to the Microsoft User Interface Automation (UIA)
> API. This single API provides a way to get to pretty much everything
> else one would usually need: window tree information, MSAA properties,
> information from HTML nodes, and of course, native UIA support for newer
> platforms like WPF and Silverlight. I regard the current interface as
> complicated, I admit; but I think it is worth learning for any JAWS
> scripter because of how much it can do.
>
> Wherever JAWS itself provides ways to get information not provided by
> this UIA interface, the UIA interface can help you find where to start
> using other methods. For example, if you need to test the style bits of
> a window though the UIA interface does not provide a means for this,
> you can find the window's UIA object via the UIA interface, get the
> nativeWindowHandle for it, and then call the JAWS getWindowStyleBits()
> function on that handle. In other words, whereas we used to think of
> navigating the window tree as the first step to finding things, I now
> think we should consider navigating the UIA tree the first step. What
> we do from there, in both cases, will depend on what we need.
>
> The definitive reference document for the JAWS UIA interface is located at
> http://www.freedomscientific.com/documentation/scripts/JAWS-UIAScriptAPI.asp.
> It is likely to be a tough read for anyone who is not already familiar
> with objects and object-oriented programming, so I imagine my post is
> going to start a lot of chatter on this list about how this system
> works.
>
> The caveats:
>
> 1. As I said, it's complicated: Scripters must understand some
> concepts of object-oriented programming and COM in order to use this
> system. Objects, in JAWS scripting at least, have long been considered
> an advanced topic. I say it's time to consider them central to
> scripting.
>
> 2. It can be slow. Wise scripters should minimize UIA queries because
> of this, by caching results, asking for as few nodes as possible by
> crafting searches carefully, etc.
>
> 3. As already mentioned, this system will not work before JAWS
> 15.0.5056. (The fine print: Some of this works as far back as JAWS 14,
> but several things aren't there that far back, some key items are
> there but with different names, etc.) This means that you can't write
> scripts this way if you want compatibility with old JAWS versions.
>
> 4. As the aforementioned Freedom Scientific reference document for the
> UIA script API says, some of the features of UIA do not work on all
> Windows versions. The document implies that support for this system
> may start in Windows 7, but I have successfully used much of this
> under Windows Vista and even XP.
>
> In conclusion:
>
> I do not think we are at the point of saying the old ways of
> navigating window trees, working directly with MSAA objects, etc. are
> obsolete and useless. I simply think the new UIA interface is the
> single most promising place for a new scripter to begin, since it
> doesn't miss much in terms of what it can let you find. Direct window
> tree traversal and FindWindow calls, MSAA getFocusObject calls and
> direct MSAA object access, etc., will sometimes run faster and should
> not be dismissed as valid pursuits. The UIA interface, though,
> certainly seems sufficient for solving many current scripting
> problems, even if in a "fix first, optimize later" sort of way.
>
> --
> Doug Lee, Senior Accessibility Programmer
> SSB BART Group - Accessibility-on-Demand
> mailto:doug.lee@xxxxxxxxxxxxxxxx http://www.ssbbartgroup.com
> "While they were saying among themselves it cannot be done,
> it was done." --Helen Keller
> __________�
>
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>
--
Soronel Haetir
soronel.haetir@xxxxxxxxx
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