Carbon: window close via accessibility API is broken

[David Reitter]

Emacs (Carbon port) seems to have trouble with Accessibility API events.

- AXPress action on the Closer button of a frame doesn't do anything
- AXPress action on Minimize seems to work
- AXPress action on Maximize produces garbage, with the window width  
being wrong. Subsequent manual redraws or scrolling lead to worse  
garbage. (I can make a screenshot available if needed.)

I'm attaching a user's bug report (below) with regard to AXPress on  
the Closer, which I can reproduce as described by him.

I looked into the reference documents he mentions but I couldn't see  
what events we're waiting for, and why this click on the window  
closer needs to be dealt with separately (does it?).

Thanks
- David


Begin forwarded message:

> From: Alexis Gallagher <address@hidden>
> Date: 4 September 2006 16:23:23 BDT
> To: David Reitter <address@hidden>
> Subject: Re: [Aquamacs-bugs] window close via accessibility API is  
> broken
>
> David,
>
> Yes. I mispoke to call them the "Cocoa accessibilty event actions".  
> They are not Cocoa-specific. Both Carbon and Cocoa apps can support  
> the accessibility api and in theory they both should. In practice,  
> much of this support comes automatically in Cocoa. It requires a  
> bit of work in Carbon, where it is therefore often neglected.
>
> Here are two relevant pages for understanding how it's supposed to  
> work:
>
> This Apple developer document "Getting Started with Accessibility",  
> especially the subsection "Developing an application", links out to  
> the differences between Cocoa and Carbon support:
>
> http://developer.apple.com/referencelibrary/GettingStarted/ 
> GS_Accessibility/
>
> Another relevant page for background is the section "The Mac OS X  
> Accessibility Protocol" in the "Accessibility Overview" document:
>
> http://developer.apple.com/documentation/Accessibility/Conceptual/ 
> AccessibilityMacOSX/index.html#//apple_ref/doc/uid/TP40001078
>
> Before filing the bug, I pulled the source from cvs and tried to to  
> understand where the relevant changes would go. But C is not my  
> strong suit, I've never touched a project of that size before, and  
> I got lost pretty quickly. Also I had some kind of problem with the  
> build script. So I thought it'd wiser just to document the bug as  
> accurately as possible. I hope this helps.
>
> cheers,
> alexis
>
> On 4 Sep 2006, at 15:39, David Reitter wrote:
>
> > Alexis,
> >
> > is this API supposed to be supported by Carbon applications as well?
> >
> > Aquamacs isn't Cocoa-based, yet.
> >
> > - David
> >
> > On 4 Sep 2006, at 15:19, Alexis Gallagher wrote:
> >
> > > I believe Aquamacs does not correctly support the Cocoa
> > > accessibiltity event actions for closing a window.
> > >
> > > I noticed this because I use a program called "Witch", a Preference
> > > Pane which offers enhanced keyboard controls for switching between
> > > applications and menus (http://www.petermaurer.de/nasi.php?
> > > section=witch). This app uses the accessibility API to send apps
> > > instructions to close individual windows. I have encoutered only two
> > > apps don't respond to those commands correctly: Firefox and  
> > > Aquamacs.
> > > This is a known issue in Firefox. It seems worth reporting it for
> > > Aquamacs as well.
> > >
> > > You can verify this behavior by using the Accessibility Inspector
> > > tool to artificially generate an AXPress event on the close  
> > > button of
> > > an Aquamacs window.  Here's how.
> > >
> > > 1) Open two frames in Aquamacs
> > > 2) Open the Accessibility Inspector (/Developer/Applications/
> > > Utilities/Accessibility Tools/Accessibility Inspector.app)
> > > 3) Place the mouse pointer over an Aquamacs window's close button
> > > 4) Type CMD-F7 to lock on that UIElement wih Accessibility Inspector
> > > 5) Hit the Perform button, which will generate an AXPress action on
> > > the close button through the accessibility API
> > > 6) Notice that the Aquamacs window fails to close, which it  
> > > should do.
> > >
> > > Since I don't know if the bug tracking machinery can take
> > > attachments, I am hosting a screenshot which demonstrates the exact
> > > behavior at the following address: http://www.alexisgallagher.com/
> > > aquamacsshot.jpg
> > >
> > >
> > >
> > > In GNU Emacs 22.0.50.1 (i386-apple-darwin8.6.1)
> > >   of 2006-06-27 on plume.sr.unh.edu - Aquamacs Distribution 0.9.9d
> > > X server distributor `Apple Computers', version 10.4.7
> > > configured using `configure '--without-x' '--prefix=/usr/local''
> > >
> > > Important settings:
> > >    value of $LC_ALL: nil
> > >    value of $LC_COLLATE: nil
> > >    value of $LC_CTYPE: nil
> > >    value of $LC_MESSAGES: nil
> > >    value of $LC_MONETARY: nil
> > >    value of $LC_NUMERIC: nil
> > >    value of $LC_TIME: nil
> > >    value of $LANG: nil
> > >    locale-coding-system: iso-8859-1
> > >    default-enable-multibyte-characters: t
> > >
> > > Major mode: Text
> > >
> > > Minor modes in effect:
> > >    iswitchb-mode: t
> > >    shell-dirtrack-mode: t
> > >    smart-frame-positioning-mode: t
> > >    aquamacs-styles-mode: t
> > >    recentf-mode: t
> > >    encoded-kbd-mode: t
> > >    osx-key-mode: t
> > >    mac-inline-input-method-mode: t
> > >    show-paren-mode: t
> > >    delete-selection-mode: t
> > >    pc-selection-mode: t
> > >    cua-mode: t
> > >    tooltip-mode: t
> > >    mouse-wheel-mode: t
> > >    menu-bar-mode: t
> > >    file-name-shadow-mode: t
> > >    global-font-lock-mode: t
> > >    font-lock-mode: t
> > >    blink-cursor-mode: t
> > >    unify-8859-on-encoding-mode: t
> > >    utf-translate-cjk-mode: t
> > >    auto-compression-mode: t
> > >    column-number-mode: t
> > >    line-number-mode: t
> > >    transient-mark-mode: t
> > >
> > > Recent input:
> > > h t t p : / / w w w . g o o g l e . c o m C-a C-c m
> > > b r o <backspace> o w s e SPC u r l <return> <return>
> > > C-k <menu-bar> <help-menu> <report-emacs-bug>
> > >
> > > Recent messages:
> > > Loading cl-extra...done
> > > Loading /Users/alexis/.xemacs/haskell/haskell-mode-2.1/haskell-site-
> > > file.el (source)...done
> > > Loading iswitchb...done
> > > Loading /Users/alexis/.xemacs/init.el (source)...done
> > > Loading /Users/alexis/Library/Preferences/Aquamacs Emacs/
> > > customizations.el (source)...done
> > > Loading /Users/alexis/Library/Preferences/Aquamacs Emacs/frame-
> > > positions.el (source)...done
> > > For an introduction to Aquamacs Emacs, type Apple-?. Copyright (C)
> > > 2006 Free
> > > Software Foundation, Inc., & D. Reitter. No Warranty. You may
> > > redistribute
> > > Aquamacs under the GNU General Public License. Type C-h C-c to view.
> > > Loading emacsbug...done
> > >
> > > ---