[Blindmath] Using Java Draw2D in an SWT GUI

Fri Feb 24 00:31:07 UTC 2012

Not trying to be contrary, but here is a direct quotation from the very top
of the page at http://www.eclipse.org/swt/

"SWT is an open source <http://www.eclipse.org/legal/> widget toolkit for
Java designed to provide efficient, portable access to the user-interface
facilities of the operating systems on which it is implemented."

No mention of the "Eclipse Rich Client Platform (Eclipse RCP)" there --
just Java.

If they had stopped at the level of "user-interface facilities," I would
have nothing to complain about and might even be happy with the product.
However, they didn't stop at that level and they succeeded in rendering
most existing Java graphics libraries unusable (from a practical
standpoint) in applications that use the SWT user interface by replacing
key Java classes, such as Image, Canvas, and numerous others with their own
incompatible versions of those classes.

Sorry, but those are simply the facts. My guess is that the requirement to
use the SWT for accessibility will deter many very capable Java programmers
from making software contributions to the needs of the blind.

Dick Baldwin

On Thu, Feb 23, 2012 at 4:27 PM, Michael Whapples <mwhapples at aim.com> wrote:

> I guess IBM/Eclipse project did give it a different name, its part of the
> Eclipse Rich Client Platform (Eclipse RCP).
>
> Michael Whapples
>
> -----Original Message----- From: Richard Baldwin
> Sent: Thursday, February 23, 2012 6:13 PM
>
> To: Blind Math list for those interested in mathematics
> Subject: Re: [Blindmath] Using Java Draw2D in an SWT GUI
>
> Michael has provided the answer to your question about the JAB.
>
> I can create workarounds.
>
> I can write complex code to make things work that don't fit together like
> they should.
>
> I can modify the code in textbooks to make it compatible with the SWT.
>
> I can modify the code in existing libraries to make them compatible with
> the SWT if the source code is available (which is what I am now being
> forced to do to provide GUI accessibity).
>
> However, the great promise of Java is the ability to use class libraries
> written using standard Java libraries without a requirement to modify those
> libraries. IBM and SWT have succeeded in breaking that promise. Therefore,
> IBM should have named their new product IBMJava (or maybe Java#) to make it
> clear that it is not Java. Once a naive programmer starts down the SWT
> route, thinking that she is programming in Java, she has just excluded most
> of the promise of Java from her programming product.
>
> Being essentially incompatible with the JFrame class, the standard Image
> class, and the standard Canvas class, to name just a few, IBM and SWT have
> made it impossible to use most existing Java graphics libraries without
> modification. The IBM versions of those classes aren't better, they are
> simply different and incompatible with standard Java. And the SWT graphics
> capability is, in my opinion, inferior to the Sun Graphic2D class.
>
> That might be a good product strategy for IBM, but it is definitely not
> good for the majority of Java programmers.
>
> Dick Baldwin
>
> On Thu, Feb 23, 2012 at 2:59 AM, Michael Whapples <mwhapples at aim.com>
> wrote:
>
>  Regarding your question on how good or bad is the JAB. Personally I like
>> the concept of the JAB from a development view, one full accessibility API
>> across all platforms, rather than one which maps to the native ones and so
>> has to cope with the differences of different platforms.
>>
>> However in practice as a user things seem to be simpler for SWT than Java
>> swing and JAB. I had some trouble getting the JAB working on a windows 7
>> 64-bit system, not sure precisely what the issue was but the JAB only
>> seemed to start working once I installed the 32-bit JVM, previously I only
>> had the 64-bit JVM installed. If the JAB does require the 32-bit JVM as
>> well as the 64-bit JVM then all I can say is this fact is not documented
>> anywhere. Even once the JAB is working the quality of accessibility can
>> differ between platforms, Linux I probably would give the best rating, on
>> windows you can even notice some issues with relatively simple
>> applications
>> such as MathTrax and on the Mac there are definitely issues (eg. the file
>> dialog for things like opening and saving files has issues on the Mac).
>>
>> In comparison SWT applications and certainly more sizable ones such as
>> eclipse tend to just work straight out of the box. This is not to say
>> their
>> always perfect but eclipse is mostly accessible and certainly most of its
>> functionality can be used by a blind user.
>>
>> Regarding your comment on reuse, may be accessibility is an example of
>> what you say. By reusing the native OS controls SWT picks up the
>> accessibility of those and the screen readers need not support another
>> accessibility API as they do for swing.
>>
>> I think though Richard's comments on reuse related more to do with non-UI
>> parts of eclipse RCP/SWT and how they just don't work with normal standard
>> JDK implementations. I think image objects were an example of this. May be
>> there is advantages to the Eclipse project versions not found in the
>> standard JDK classes.
>>
>>
>> Michael Whapples
>>
>> -----Original Message----- From: Carolyn MacLeod
>> Sent: Thursday, February 23, 2012 5:04 AM
>>
>> To: Blind Math list for those interested in mathematics
>> Subject: Re: [Blindmath] Using Java Draw2D in an SWT GUI
>>
>> Hi again.
>>
>> Sorry to take so long to reply.
>>
>> JFrame is not an embeddable component, so SWT (or any other embeddor)
>> can't embed JFrames.
>> SWT_AWT.new_Frame() returns a subclass of EmbeddedFrame, which is a
>> sibling of JFrame but it does not have a root pane.
>> JApplet is embeddable and it has a root pane. Can you make do with a
>> JApplet instead of a JFrame?
>>
>> I wrote another snippet for you (attached) that takes the root pane out of
>> a JFrame and sets it into a JApplet in an SWT GUI.
>> Hopefully you could do something similar with a JFrame from your
>> textbook's sample code.
>> But this won't solve the whole problem, because the Swing controls from
>> the JFrame still won't be accessible unless you have the JAB installed and
>> use an AT that works with it.
>> (Question for you: Are Swing controls really that inaccessible? Is the JAB
>> hard to install? Don't AT usually work once the JAB is installed? I don't
>> know because I don't use Swing.)
>>
>> Regarding event integration, this article might be helpful:
>> http://www.eclipse.org/****articles/Article-Swing-SWT-**<http://www.eclipse.org/**articles/Article-Swing-SWT-**>
>> Integration/index.html<http://**www.eclipse.org/articles/**
>> Article-Swing-SWT-Integration/**index.html<http://www.eclipse.org/articles/Article-Swing-SWT-Integration/index.html>
>> >
>>
>> The rule of thumb is to use SwingUtilities.invokeLater() and
>> Display.asyncExec() to pass work from AWT/Swing to SWT and vice-versa.
>> This article also discusses the tab traversal "glitch" that I tripped over
>> in the snippet I sent you earlier, and they show how to fix it in their
>> example code.
>>
>>  I really do believe in the OOP concept of "reuse, don't reinvent,"
>>
>>>
>>>  So do we, which is why we reused the OS controls instead of drawing our
>> own.  :)
>> We did talk about this with Sun in the beginning, but unfortunately it
>> didn't work out.
>>
>> Also, I happened to trip over these other two snippets that manipulate
>> BufferedImage and JAI TiledImage from within SWT.
>> I am including them here in case they are helpful:
>> https://bugs.eclipse.org/bugs/****show_bug.cgi?id=119363#c13<https://bugs.eclipse.org/bugs/**show_bug.cgi?id=119363#c13>
>> <h**ttps://bugs.eclipse.org/bugs/**show_bug.cgi?id=119363#c13<https://bugs.eclipse.org/bugs/show_bug.cgi?id=119363#c13>
>> >
>> https://bugs.eclipse.org/bugs/****show_bug.cgi?id=119363#c14<https://bugs.eclipse.org/bugs/**show_bug.cgi?id=119363#c14>
>> <h**ttps://bugs.eclipse.org/bugs/**show_bug.cgi?id=119363#c14<https://bugs.eclipse.org/bugs/show_bug.cgi?id=119363#c14>
>> >
>>
>>
>> Hope this helps,
>> Carolyn
>>
>>
>>
>>
>>
>>
>>
>> From:
>> Richard Baldwin <baldwin at dickbaldwin.com>
>> To:
>> Blind Math list for those interested in mathematics <blindmath at nfbnet.org
>> >
>> Date:
>> 01/31/2012 01:30 PM
>> Subject:
>> Re: [Blindmath] Using Java Draw2D in an SWT GUI
>> Sent by:
>> blindmath-bounces at nfbnet.org
>>
>>
>>
>> Thanks for responding to my concerns. I will definitely take a look at
>> your
>> workabound and see how much it helps. Hopefully, I will be pleased with
>> the
>> results.
>>
>> I suspect, however, that simply providing compatibility at the AWT Canvas
>> level won't help much with my main concern. I already knew of one way to
>> do
>> that. I also already knew how to embed AWT Frame objects in an SWT object.
>> Unfortunately, I don't know how to easily integrate events fired by those
>> AWT components into the SWT event handling system and I don't know how to
>> embed Swing JFrame objects and/or their events in SWT objects.
>>
>> I know how to write new code that will play reasonably well with SWT. That
>> isn't my main concern. I really do believe in the OOP concept of "reuse,
>> don't reinvent," and my main concern is the lack of compatibility of SWT
>> with existing unmodified graphics libraries, which typically produce
>> graphic outputs in Swing JFrame objects. Until we can successfully embed
>> JFrame objects in SWT objects, and until we can easily integrate the event
>> handling mechanisms of the two systems, the use of those libraries without
>> modification of the libraries will probably be very difficult at best and
>> off limits at worst.
>>
>> Hopefully someone will prove me wrong on this.
>>
>> Dick Baldwin
>>
>> On Tue, Jan 31, 2012 at 11:03 AM, Carolyn MacLeod <
>> Carolyn_MacLeod at ca.ibm.com> wrote:
>>
>>  Thank-you, Michael!
>>
>>> Carolyn
>>>
>>>
>>>
>>> From:
>>> "Michael Whapples" <mwhapples at aim.com>
>>> To:
>>> "Blind Math list for those interested in mathematics"
>>> <blindmath at nfbnet.org>
>>> Date:
>>> 31/01/2012 11:30 AM
>>> Subject:
>>> Re: [Blindmath] Using Java Draw2D in an SWT GUI
>>> Sent by:
>>> blindmath-bounces at nfbnet.org
>>>
>>>
>>>
>>> Hello,
>>> Thanks for taking the time to do this. I know you have asked questions
>>>
>>>  on
>>
>>  the orca-list about improving accessibility in SWT and eclipse and its
>>> certainly appreciated. In my oppinion SWT is one of the few, if not the
>>> best, GUI toolkits for making accessible applications which are also
>>> cross-platform.
>>>
>>> Regards
>>>
>>> Michael whapples
>>>
>>> -----Original Message-----
>>> From: Carolyn MacLeod
>>> Sent: Tuesday, January 31, 2012 4:09 PM
>>> To: blindmath at nfbnet.org
>>> Subject: [Blindmath] Using Java Draw2D in an SWT GUI
>>>
>>> Hello, list.
>>>
>>> My name is Carolyn and I am on the Eclipse SWT Team.
>>> I am the developer responsible for SWT Accessibility.
>>>
>>> Ken Perry of Blinksoft asked me if I could help with an issue brought up
>>> by Richard Baldwin regarding SWT being accessible but largely
>>>
>>>  incompatible
>>
>>  with Swing/AWT.
>>> I read several posts similar to this one:
>>>
>>>
>>>  http://host.nfbnet.org/****pipermail/blindmath_nfbnet.**<http://host.nfbnet.org/**pipermail/blindmath_nfbnet.**>
>>>
>> org/2012-January/004693.html<h**ttp://host.nfbnet.org/**
>> pipermail/blindmath_nfbnet.**org/2012-January/004693.html<http://host.nfbnet.org/pipermail/blindmath_nfbnet.org/2012-January/004693.html>
>> >
>>
>>
>>
>>> I wrote an SWT Snippet that I hope you will find useful:
>>>
>>>
>>>  http://git.eclipse.org/c/****platform/eclipse.platform.swt.****<http://git.eclipse.org/c/**platform/eclipse.platform.swt.**>
>>>
>> git/tree/examples/org.eclipse.****swt.snippets/src/org/**eclipse/**
>> swt/snippets/Snippet361.java<h**ttp://git.eclipse.org/c/**
>> platform/eclipse.platform.swt.**git/tree/examples/org.eclipse.**
>> swt.snippets/src/org/eclipse/**swt/snippets/Snippet361.java<http://git.eclipse.org/c/platform/eclipse.platform.swt.git/tree/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet361.java>
>> >
>>
>>
>>
>>  It shows how to host an AWT Canvas inside an SWT GUI, and use the GUI to
>>> initiate Java2D operations within the Canvas.
>>> I randomly chose rotation and translation of the image, but you should
>>>
>>>  be
>>
>>  able to modify the snippet to do whatever Java2D operations you are
>>> teaching.
>>> The "Print Image" button uses SWT to take a screen snapshot of the
>>>
>>>  Canvas
>>
>>  and print it to a printer.
>>> I had not heard of a printer that embosses images before, and I think
>>>
>>>  that
>>
>>  is really cool!
>>>
>>> I tried this snippet on Windows (XP) with JAWS (13) and on Mac OSX
>>> (Leopard) with VoiceOver, and on Linux (Ubuntu 10.04) with Orca and it
>>> worked on all 3 platforms.
>>> It should work with other platform versions and screen readers as well.
>>> The only glitch I encountered was on Windows, if the user tabs into the
>>> Canvas, they can't tab back out.
>>> They need to use the button mnemonics to traverse out of the Canvas:
>>>
>>>  alt+o
>>
>>  for Open, alt+x and alt+y for translating X and Y, alt+r for Rotate, and
>>> alt+p for Print.
>>> This was not an issue on Mac or Linux.
>>>
>>> I cannot solve the deeper issues, like making SWT and AWT graphics
>>> interchangeable without performance penalties (there are technical
>>> issues),
>>> or improving SWT's graphics support to the level of Java2D or more (we
>>>
>>>  are
>>
>>  a very small and very busy team, and we simply do not have the
>>>
>>>  manpower).
>>
>>  Hopefully this snippet will give you a work-around that is both
>>>
>>>  accessible
>>
>>  and teaches the math you want to teach.
>>>
>>> Carolyn
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>>
>> --
>> Richard G. Baldwin (Dick Baldwin)
>> Home of Baldwin's on-line Java Tutorials
>> http://www.DickBaldwin.com
>>
>> Professor of Computer Information Technology
>> Austin Community College
>> (512) 223-4758
>> mailto:Baldwin at DickBaldwin.com
>> http://www.austincc.edu/****baldwin/ <http://www.austincc.edu/**baldwin/><
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>
> --
> Richard G. Baldwin (Dick Baldwin)
> Home of Baldwin's on-line Java Tutorials
> http://www.DickBaldwin.com
>
> Professor of Computer Information Technology
> Austin Community College
> (512) 223-4758
> mailto:Baldwin at DickBaldwin.com
> http://www.austincc.edu/**baldwin/ <http://www.austincc.edu/baldwin/>
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-- 
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Professor of Computer Information Technology
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