Re: [Accessibility-ia2] Plea for a new function
Hi Brett, Out of curiosity, how are you getting the text leaf nodes in the first place? Ideally, this should all be done using the IAccessibleText interface on the parent. I'm keenly aware that there are cases where this isn't practical, but I thought I'd ask nevertheless. Jamie On 27/11/2012 5:14 AM, Brett Lewis wrote: Hi, I don't have a strong preference for a given solution. If everyone prefers implementing IAccessibleHyperLink on the leaf nodes, that is fine. Alex said it would be hard to implement IAccessibleText on all the text leaf nodes so Jamie's IAccessibleHyperLink solution or A pair of new functions to retrieve child at offset and offset of descendant seem like the only options. As I said, the two cases of concern for me are identifying the text attributes for a given text leaf node that doesn't support IaccessibleText and to obtain the rectangle enclosing specific characters in a text leaf node. Thanks, Brett -Original Message- From: accessibility-ia2-boun...@lists.linuxfoundation.org [mailto:accessibility-ia2-boun...@lists.linuxfoundation.org] On Behalf Of Alexander Surkov Sent: Tuesday, November 20, 2012 8:30 PM To: James Teh Cc: IAccessible2 mailing list Subject: Re: [Accessibility-ia2] Plea for a new function Hi, Jamie. I think Brett meant accessible object for text node (aka text leaf accessible). In general accessible objects for text nodes aren't really necessary since they dupe info that is provided by IAccessibleText on the container. So there's no need for them in IA2 world, they are rather MSAA heritage. However I has been told that having accessible objects for text nodes is still useful for AT (I'm not really aware of details) and that's why we keep them in Firefox btw. This is a reason why I don't want text nodes to implement IAccessibleText (besides it won't be trivial to implement). IAccessibleHyperlink idea might be ok, it's not backward compatible though and makes nsIAccessibleHyperText nearly useless since it dupes IAccessbile/IAccessbile2 methods. Having a new method that returns an offset for a child (and child by offset?) might be ok. Thank you. Alex. On Wed, Nov 21, 2012 at 9:11 AM, James Teh ja...@nvaccess.org wrote: Hi. There are two problems here: 1. It's unclear what is considered the text of a descendant node which doesn't support IAccessibleText. It could be accName, accValue, accDescription, etc. or some combination thereof. 2. This assumes that a descendant node's text actually is contained in the ancestor IAccessibleText object, which might not be the case. Of course, I guess the method could just fail if this weren't the case. Also, why not just implement IAccessibleText on the descendant nodes? In any case, I don't think a new method is required for this. You can implement IAccessibleHyperlink on the descendant nodes. The startIndex and endIndex properties of IAccessibleHyperlink should give you what you need. Jamie On 21/11/2012 9:30 AM, Brett Lewis wrote: All: I have recently run into a situation for which there presently doesn't appear to be a good solution. 1. The problem. I wished to obtain the attributes for the text at a particular offset. This is straightforward using IAccessibleText and just asking for the attributes at the offset of interest. The difficulty is that the node whose text attributes I wanted didn't support IAccessibleText. One of its ancestors did and this ancestor did contain information about the attributes I needed. The question then became, how can I find out where in a given IAccessibleText string does a descendants node text begin. I haven't found an easy way to answer this question. 2. Proposed solution: Add a new function that returns the offset in the current IAccessibleText text string for a given IAccessible for a descendant. So something like: DescendantOffset(IAccessible* acc,VARIANT varChild, long* offset) I have no strong preference for exactly how this should be handled, just the need for such a function. I know the 1.3 version of the IAccessible2 specification is nearly ready, but I would like to see if this new function could be included. In addition to the attributes for text at a given offset, I have also seen a case where we needed the rectangle for particular characters. Again, in this instance, we needed to locate the nearest ancestor supporting IAccessibleText and try to determine the offset in this ancestor of the node of interest. What does everyone think about such an addition? Any feedback would be much appreciated. Thanks, Brett Lewis ___ Accessibility-ia2 mailing list Accessibility-ia2@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/accessibility-ia2 -- James Teh Director, NV Access Limited Email: ja...@nvaccess.org Web site: http://www.nvaccess.org/ Phone: +61 7 5667 8372 ___ Accessibility-ia2 mailing list
Re: [Accessibility-ia2] Plea for a new function
Hi, I am getting the Iaccessible tree. I then find that I want the text attributes for one of my leaf nodes and find that I have to go back up the Iaccessible tree to find the nearest Iaccessible node that allow QI to IAccessibleText and then trying to figure out how to map the result back down to my Iaccessible leaf node. You can see a case by just adding a sup tag to a web page: 2sup32/sup And view it in firefox, there is a paragraph Iaccessible with two text children. The two text children correspond to 2 and 32. Each of these leaf nodes does not support the IAccessibleText but the paragraph parent does. This is a pretty trivial case but illustrates what I am talking about. Brett -Original Message- From: accessibility-ia2-boun...@lists.linuxfoundation.org [mailto:accessibility-ia2-boun...@lists.linuxfoundation.org] On Behalf Of James Teh Sent: Monday, November 26, 2012 1:28 PM To: IAccessible2 mailing list Subject: Re: [Accessibility-ia2] Plea for a new function Hi Brett, Out of curiosity, how are you getting the text leaf nodes in the first place? Ideally, this should all be done using the IAccessibleText interface on the parent. I'm keenly aware that there are cases where this isn't practical, but I thought I'd ask nevertheless. Jamie On 27/11/2012 5:14 AM, Brett Lewis wrote: Hi, I don't have a strong preference for a given solution. If everyone prefers implementing IAccessibleHyperLink on the leaf nodes, that is fine. Alex said it would be hard to implement IAccessibleText on all the text leaf nodes so Jamie's IAccessibleHyperLink solution or A pair of new functions to retrieve child at offset and offset of descendant seem like the only options. As I said, the two cases of concern for me are identifying the text attributes for a given text leaf node that doesn't support IaccessibleText and to obtain the rectangle enclosing specific characters in a text leaf node. Thanks, Brett -Original Message- From: accessibility-ia2-boun...@lists.linuxfoundation.org [mailto:accessibility-ia2-boun...@lists.linuxfoundation.org] On Behalf Of Alexander Surkov Sent: Tuesday, November 20, 2012 8:30 PM To: James Teh Cc: IAccessible2 mailing list Subject: Re: [Accessibility-ia2] Plea for a new function Hi, Jamie. I think Brett meant accessible object for text node (aka text leaf accessible). In general accessible objects for text nodes aren't really necessary since they dupe info that is provided by IAccessibleText on the container. So there's no need for them in IA2 world, they are rather MSAA heritage. However I has been told that having accessible objects for text nodes is still useful for AT (I'm not really aware of details) and that's why we keep them in Firefox btw. This is a reason why I don't want text nodes to implement IAccessibleText (besides it won't be trivial to implement). IAccessibleHyperlink idea might be ok, it's not backward compatible though and makes nsIAccessibleHyperText nearly useless since it dupes IAccessbile/IAccessbile2 methods. Having a new method that returns an offset for a child (and child by offset?) might be ok. Thank you. Alex. On Wed, Nov 21, 2012 at 9:11 AM, James Teh ja...@nvaccess.org wrote: Hi. There are two problems here: 1. It's unclear what is considered the text of a descendant node which doesn't support IAccessibleText. It could be accName, accValue, accDescription, etc. or some combination thereof. 2. This assumes that a descendant node's text actually is contained in the ancestor IAccessibleText object, which might not be the case. Of course, I guess the method could just fail if this weren't the case. Also, why not just implement IAccessibleText on the descendant nodes? In any case, I don't think a new method is required for this. You can implement IAccessibleHyperlink on the descendant nodes. The startIndex and endIndex properties of IAccessibleHyperlink should give you what you need. Jamie On 21/11/2012 9:30 AM, Brett Lewis wrote: All: I have recently run into a situation for which there presently doesn't appear to be a good solution. 1. The problem. I wished to obtain the attributes for the text at a particular offset. This is straightforward using IAccessibleText and just asking for the attributes at the offset of interest. The difficulty is that the node whose text attributes I wanted didn't support IAccessibleText. One of its ancestors did and this ancestor did contain information about the attributes I needed. The question then became, how can I find out where in a given IAccessibleText string does a descendants node text begin. I haven't found an easy way to answer this question. 2. Proposed solution: Add a new function that returns the offset in the current IAccessibleText text string for a given IAccessible for a descendant. So something like: DescendantOffset(IAccessible* acc,VARIANT varChild, long*
