[jawsscripts] Re: Opinion post: Time to change where new scripters begin
- From: "Alex H." <linuxx64.bashsh@xxxxxxxxx>
- To: jawsscripts@xxxxxxxxxxxxx
- Date: Thu, 27 Feb 2014 10:56:06 -0500
Agreed with the thread. Also, I'd point out that UIA is quite a lot
newer than MSAA, and has improvements and fixes over it. It makes
sense to start someone learning valid and current APIs.
Alex
On 2/27/14, Soronel Haetir <soronel.haetir@xxxxxxxxx> wrote:
> 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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>
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