1809761 - [CTW] Incorrect text bounds when interleaving block- and inline-frame accessibles

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect)

Description

[Morgan Reschenberg [:morgan]]

Summary of potentially-relevant matrix discussion:

• The frame tree for the example below has a one block frame root with a unique inline frame parent for each text leaf (the code element becomes several frames)
• The accessible we generate for the code element has only one frame (the primary frame, whatever that is)
• We use TransformRect to compute the offset between subtree-spanning continuations -- transforming the continuation to the hypertext's frame. The hypertext's frame (in this instance) is not necessarily an ancestor of the continuation's frame, since the primary frame for the code element is only the parent to one (the first?) text leaf.

Here's a test case:

/**
 * Test character bounds in an intervening inline element with non-br line breaks
 */
addAccessibleTask(
  `
  <style>
    @font-face {
      font-family: Ahem;
      src: url(${CURRENT_CONTENT_DIR}e10s/fonts/Ahem.sjs);
    }
    pre {
      font: 20px/20px Ahem;
    }
  </style>
  <pre><code id="t" role="group">XX
XXX
XX
X</pre>`,
  async function(browser, docAcc) {
    await testChar(docAcc, browser, "t", 0);
    await testChar(docAcc, browser, "t", 3);
    await testChar(docAcc, browser, "t", 7);
    await testChar(docAcc, browser, "t", 10);
  },
  {
    chrome: true,
    topLevel: !isWinNoCache,
    iframe: !isWinNoCache,
  }
);

Comment 1

[James Teh [:Jamie]]

I'm wondering whether we can fix this by calling TransformRect with the continuation frame and the primary text frame rather than the ancestor frame. That is:

// ... No need for nearestAccAncestorFrame
if (prevTextFrame->GetParent() != currTextFrame->GetParent()) {
  contRect = frameRect;
  nsLayoutUtils::TransformRect(currTextFrame, frame, contRect);
}

Comment 2

[James Teh [:Jamie]]

As with bug 1809695, this is broken in the parent process (LocalAccessible) as well. I think we may have a JS test harness bug here rather than a C++ bounds bug.

Comment 3

[Morgan Reschenberg [:morgan]]

Attachment: Bug 1809761: Introduce text bounds test for interleaving block- and inline-frame accessibles r?Jamie

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

There's a r+ patch which didn't land and no activity in this bug for 2 weeks.
:morgan, could you have a look please?
If you still have some work to do, you can add an action "Plan Changes" in Phabricator.
For more information, please visit auto_nag documentation.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8ab29a76ed86
Introduce text bounds test for interleaving block- and inline-frame accessibles r=Jamie

Comment 6

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/8ab29a76ed86