822983 - Map SVG graphic elements to accessibility API

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect)

Description

[alexander :surkov (:asurkov)]

http://www.w3.org/TR/SVG/intro.html#TermGraphicsElement:

graphics element
    One of the element types that can cause graphics to be drawn onto the target canvas. Specifically: ‘circle’, ‘ellipse’, ‘image’, ‘line’, ‘path’, ‘polygon’, ‘polyline’, ‘rect’, ‘text’ and ‘use’.

Comment 1

[alexander :surkov (:asurkov)]

Attachment: patch

Comment 2

[alexander :surkov (:asurkov)]

Btw, probably these elements should implement IA2 IAccessibleImage interface. I can do that as follow up if it's needed. Mick, let me know if NVDA relies on it.

And svg:image element should expose @src object attribute at least to be consistent with HTML/XUL images. I can do that if that's needed as well.

Comment 3

[Robert Longson [:longsonr]]

Comment on attachment 693805 [details] [diff] [review]
patch

>+      } else if (content->Tag() == nsGkAtoms::rect ||
>+                 content->Tag() == nsGkAtoms::circle ||
>+                 content->Tag() == nsGkAtoms::ellipse ||
>+                 content->Tag() == nsGkAtoms::line ||
>+                 content->Tag() == nsGkAtoms::path ||
>+                 content->Tag() == nsGkAtoms::polygon ||
>+                 content->Tag() == nsGkAtoms::polyline ||
>+                 content->Tag() == nsGkAtoms::image) {

Perhaps you should check that the frame is a nsGkAtoms::svgPathGeometryFrame instead?

Comment 4

[alexander :surkov (:asurkov)]

(In reply to Robert Longson from comment #3)
> Comment on attachment 693805 [details] [diff] [review]
> patch
> 
> >+      } else if (content->Tag() == nsGkAtoms::rect ||
> >+                 content->Tag() == nsGkAtoms::circle ||
> >+                 content->Tag() == nsGkAtoms::ellipse ||
> >+                 content->Tag() == nsGkAtoms::line ||
> >+                 content->Tag() == nsGkAtoms::path ||
> >+                 content->Tag() == nsGkAtoms::polygon ||
> >+                 content->Tag() == nsGkAtoms::polyline ||
> >+                 content->Tag() == nsGkAtoms::image) {
> 
> Perhaps you should check that the frame is a nsGkAtoms::svgPathGeometryFrame
> instead?

is it equivalent to all these checks? (including imgage?)

Comment 5

[Robert Longson [:longsonr]]

image frames are nsGkAtoms::svgImageFrame but their implementation is basically

class nsSVGImageFrame : public nsSVGPathGeometryFrame 

So something like this should work

nsSVGPathGeometryFrame* pathGeometryFrame = do_QueryFrame(frame);
if (pathGeometryFrame) {
}

Comment 6

[alexander :surkov (:asurkov)]

Ok, nice, I will update the patch. Thanks!

Comment 7

[alexander :surkov (:asurkov)]

(In reply to Robert Longson from comment #5)
> image frames are nsGkAtoms::svgImageFrame but their implementation is
> basically
> 
> class nsSVGImageFrame : public nsSVGPathGeometryFrame 
> 
> So something like this should work
> 
> nsSVGPathGeometryFrame* pathGeometryFrame = do_QueryFrame(frame);
> if (pathGeometryFrame) {
> }

do_QueryFrame gives an error:

c:\mozilla\1912\obj-ff-dbg\dist\include\nsQueryFrame.h(69) : error C2385: ambiguous access of 'kFrameIID'
        could be the 'kFrameIID' in base 'nsIFrame'
        or could be the 'kFrameIID' in base 'nsISVGChildFrame'
        c:/mozilla/1912/accessible/src/base/nsAccessibilityService.cpp(920) : see reference to function template instantiation 'do_QueryFrame::operator Dest(void)<nsSVGPathGeometryFrame>' being compiled
        with
        [
            Dest=nsSVGPathGeometryFrame
        ] 

cause by missed NS_DECL_QUERYFRAME_TARGET(nsSVGPathGeometryFrame) I think.

Alternatively we could use nsIFrame::AccessibleType() approach.

Comment 8

[alexander :surkov (:asurkov)]

Attachment: patch2

Comment 9

[Trevor Saunders (:tbsaunde)]

Comment on attachment 694231 [details] [diff] [review]
patch2

It might be nice to use tree test to make sure kids are correct to

Comment 10

[alexander :surkov (:asurkov)]

(In reply to Trevor Saunders (:tbsaunde) from comment #9)

> It might be nice to use tree test to make sure kids are correct to

they don't really have kids and don't expose hierarchies. that's why I pushed them as plain roles check.

Comment 11

[Michael Curran]

(In reply to alexander :surkov from comment #2)
> Btw, probably these elements should implement IA2 IAccessibleImage
> interface. I can do that as follow up if it's needed. Mick, let me know if
> NVDA relies on it.
> And svg:image element should expose @src object attribute at least to be
> consistent with HTML/XUL images. I can do that if that's needed as well.
We do not make use of IAccessibleImage in NVDA. However, src attribute might be nice.

Comment 12

[alexander :surkov (:asurkov)]

bug 824320 filed for scr object attribute

Comment 13

[alexander :surkov (:asurkov)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/cf9f18d9c698

Comment 14

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/cf9f18d9c698