Make spin button accessible on Mac.

content/browser/accessibility/browser_accessibility_cocoa.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <execinfo.h>
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <map>
 
@@ skipping 127 matching lines @@
     { AccessibilityNodeData::ROLE_REGION, NSAccessibilityGroupRole },
     { AccessibilityNodeData::ROLE_ROOT_WEB_AREA, @"AXWebArea" },
     { AccessibilityNodeData::ROLE_ROW, NSAccessibilityRowRole },
     { AccessibilityNodeData::ROLE_ROW_HEADER, @"AXCell" },
     { AccessibilityNodeData::ROLE_RULER, NSAccessibilityRulerRole },
     { AccessibilityNodeData::ROLE_RULER_MARKER,
         NSAccessibilityRulerMarkerRole },
     // TODO(dtseng): we don't correctly support the attributes for these roles.
     // { AccessibilityNodeData::ROLE_SCROLLAREA,
     //    NSAccessibilityScrollAreaRole },
-    // { AccessibilityNodeData::ROLE_SCROLLBAR, NSAccessibilityScrollBarRole },
+    { AccessibilityNodeData::ROLE_SCROLLBAR, NSAccessibilityScrollBarRole },
     { AccessibilityNodeData::ROLE_SHEET, NSAccessibilitySheetRole },
     { AccessibilityNodeData::ROLE_SLIDER, NSAccessibilitySliderRole },
     { AccessibilityNodeData::ROLE_SLIDER_THUMB, NSAccessibilityGroupRole },
-    { AccessibilityNodeData::ROLE_SPIN_BUTTON, NSAccessibilityTextFieldRole },
+    { AccessibilityNodeData::ROLE_SPIN_BUTTON, NSAccessibilitySliderRole },

[David Tseng, 2012/09/13 19:00:57]

I think we actually want to map to NSAccessibilityIncrementorRole.

[dmazzoni, 2012/09/13 19:32:29]

That's what WebKit maps it to on Mac, but it doesn't work.
NSAccessibilityIncrementorRole is intended for the plus button next to a
Mac-native spin button - and NSAccessibilityIncrementorRole is intended for the
minus button. In a native spin button, the text field is just a text field.

As far as I can tell, there's no native Mac control that corresponds to a spin
button on Windows, so this is the closest approximation I could find that I can
actually get to work.

[David Tseng, 2012/09/13 22:00:28]

On 2012/09/13 19:32:29, Dominic Mazzoni wrote:

Actually, I just tried an example on Mac and the mapping is to a progress
indicator.

     { AccessibilityNodeData::ROLE_SPLITTER, NSAccessibilitySplitterRole },
     { AccessibilityNodeData::ROLE_SPLIT_GROUP, NSAccessibilitySplitGroupRole },
     { AccessibilityNodeData::ROLE_STATIC_TEXT, NSAccessibilityStaticTextRole },
     { AccessibilityNodeData::ROLE_STATUS, NSAccessibilityGroupRole },
     { AccessibilityNodeData::ROLE_SYSTEM_WIDE, NSAccessibilityUnknownRole },
     { AccessibilityNodeData::ROLE_TAB, NSAccessibilityRadioButtonRole },
     { AccessibilityNodeData::ROLE_TAB_LIST, NSAccessibilityTabGroupRole },
     { AccessibilityNodeData::ROLE_TAB_PANEL, NSAccessibilityGroupRole },
     { AccessibilityNodeData::ROLE_TABLE, NSAccessibilityTableRole },
     { AccessibilityNodeData::ROLE_TABLE_HEADER_CONTAINER,
@@ skipping 99 matching lines @@
   } attributeToMethodNameContainer[] = {
     { NSAccessibilityChildrenAttribute, @"children" },
     { NSAccessibilityColumnsAttribute, @"columns" },
     { NSAccessibilityDescriptionAttribute, @"description" },
     { NSAccessibilityEnabledAttribute, @"enabled" },
     { NSAccessibilityFocusedAttribute, @"focused" },
     { NSAccessibilityHelpAttribute, @"help" },
     { NSAccessibilityMaxValueAttribute, @"maxValue" },
     { NSAccessibilityMinValueAttribute, @"minValue" },
     { NSAccessibilityNumberOfCharactersAttribute, @"numberOfCharacters" },
+    { NSAccessibilityOrientationAttribute, @"orientation" },
     { NSAccessibilityParentAttribute, @"parent" },
     { NSAccessibilityPositionAttribute, @"position" },
     { NSAccessibilityRoleAttribute, @"role" },
     { NSAccessibilityRoleDescriptionAttribute, @"roleDescription" },
     { NSAccessibilityRowsAttribute, @"rows" },
     { NSAccessibilitySizeAttribute, @"size" },
     { NSAccessibilitySubroleAttribute, @"subrole" },
     { NSAccessibilityTabsAttribute, @"tabs" },
     { NSAccessibilityTitleAttribute, @"title" },
     { NSAccessibilityTitleUIElementAttribute, @"titleUIElement" },
     { NSAccessibilityTopLevelUIElementAttribute, @"window" },
     { NSAccessibilityURLAttribute, @"url" },
     { NSAccessibilityValueAttribute, @"value" },
+    { NSAccessibilityValueDescriptionAttribute, @"valueDescription" },
     { NSAccessibilityVisibleCharacterRangeAttribute, @"visibleCharacterRange" },
     { NSAccessibilityWindowAttribute, @"window" },
     { @"AXAccessKey", @"accessKey" },
     { @"AXARIAAtomic", @"ariaAtomic" },
     { @"AXARIABusy", @"ariaBusy" },
     { @"AXARIALive", @"ariaLive" },
     { @"AXARIARelevant", @"ariaRelevant" },
     { @"AXLoaded", @"loaded" },
     { @"AXLoadingProgress", @"loadingProgress" },
     { @"AXRequired", @"required" },
@@ skipping 196 matching lines @@
   return [NSNumber numberWithFloat:floatValue];
 }
 
 - (NSNumber*)minValue {
   float floatValue = 0.0;
   browserAccessibility_->GetFloatAttribute(
       AccessibilityNodeData::ATTR_MIN_VALUE_FOR_RANGE, &floatValue);
   return [NSNumber numberWithFloat:floatValue];
 }
 
+- (NSString*)orientation {
+  // We present a spin button as a vertical slider, with a role description
+  // of "spin button".

[David Tseng, 2012/09/13 22:00:28]

Can we at least call it something more familiar like "stepper" so that users
will know it is meant to be adjusted and not pressed?

I know there's lack of standardization here (i.e. Jaws calls role=spinbutton
"spin box").

+  AccessibilityNodeData::Role internal_role =
+      static_cast<AccessibilityNodeData::Role>(browserAccessibility_->role());
+  if (internal_role == AccessibilityNodeData::ROLE_SPIN_BUTTON)
+    return NSAccessibilityVerticalOrientationValue;
+
+  if (GetState(browserAccessibility_, AccessibilityNodeData::STATE_VERTICAL))
+    return NSAccessibilityVerticalOrientationValue;
+  else
+    return NSAccessibilityHorizontalOrientationValue;
+}
+
 - (NSNumber*)numberOfCharacters {
   return [NSNumber numberWithInt:browserAccessibility_->value().length()];
 }
 
 // The origin of this accessibility object in the page's document.
 // This is relative to webkit's top-left origin, not Cocoa's
 // bottom-left origin.
 - (NSPoint)origin {
   gfx::Rect bounds = browserAccessibility_->GetLocalBoundsRect();
   return NSMakePoint(bounds.x(), bounds.y());
@@ skipping 65 matching lines @@
         if (htmlAttribute.first == ASCIIToUTF16("role")) {
           // TODO(dtseng): This is not localized; see crbug/84814.
           return base::SysUTF16ToNSString(htmlAttribute.second);
         }
       }
     }
   }
 
   AccessibilityNodeData::Role internal_role =
       static_cast<AccessibilityNodeData::Role>(browserAccessibility_->role());
-  if (internal_role == AccessibilityNodeData::ROLE_FOOTER) {
-      return base::SysUTF16ToNSString(content_client->GetLocalizedString(
-          IDS_AX_ROLE_FOOTER));
+  switch(internal_role) {
+  case AccessibilityNodeData::ROLE_FOOTER:
+    return base::SysUTF16ToNSString(content_client->GetLocalizedString(
+        IDS_AX_ROLE_FOOTER));
+  case AccessibilityNodeData::ROLE_SPIN_BUTTON:
+    return base::SysUTF16ToNSString(content_client->GetLocalizedString(
+        IDS_AX_ROLE_SPIN_BUTTON));
+  default:
+    break;
   }
 
   return NSAccessibilityRoleDescription(role, nil);
 }
 
 - (NSArray*)rows {
   NSMutableArray* ret = [[[NSMutableArray alloc] init] autorelease];
   for (BrowserAccessibilityCocoa* child in [self children]) {
     if ([[child role] isEqualToString:NSAccessibilityRowRole])
       [ret addObject:child];
@@ skipping 114 matching lines @@
     float floatValue;
     if (browserAccessibility_->GetFloatAttribute(
             AccessibilityNodeData::ATTR_VALUE_FOR_RANGE, &floatValue)) {
       return [NSNumber numberWithFloat:floatValue];
     }
   }
 
   return base::SysUTF16ToNSString(browserAccessibility_->value());
 }
 
+- (NSString*)valueDescription {
+  if (!browserAccessibility_->value().empty())
+    return base::SysUTF16ToNSString(browserAccessibility_->value());
+  else
+    return nil;
+}
+
 - (NSValue*)visibleCharacterRange {
   return [NSValue valueWithRange:
       NSMakeRange(0, browserAccessibility_->value().length())];
 }
 
 - (NSNumber*)visited {
   return [NSNumber numberWithBool:
       GetState(browserAccessibility_, AccessibilityNodeData::STATE_TRAVERSED)];
 }
 
@@ skipping 202 matching lines @@
         NSAccessibilityVisibleCharacterRangeAttribute,
         nil]];
   } else if ([role isEqualToString:NSAccessibilityTabGroupRole]) {
     [ret addObject:NSAccessibilityTabsAttribute];
   } else if ([role isEqualToString:NSAccessibilityProgressIndicatorRole] ||
              [role isEqualToString:NSAccessibilitySliderRole] ||
              [role isEqualToString:NSAccessibilityScrollBarRole]) {
     [ret addObjectsFromArray:[NSArray arrayWithObjects:
         NSAccessibilityMaxValueAttribute,
         NSAccessibilityMinValueAttribute,
+        NSAccessibilityOrientationAttribute,
+        NSAccessibilityValueDescriptionAttribute,
         nil]];
   }
 
   // Live regions.
   string16 s;
   if (browserAccessibility_->GetStringAttribute(
           AccessibilityNodeData::ATTR_LIVE_STATUS, &s)) {
     [ret addObjectsFromArray:[NSArray arrayWithObjects:
         @"AXARIALive",
         @"AXARIARelevant",
@@ skipping 49 matching lines @@
 
   return NO;
 }
 
 // Returns whether or not this object should be ignored in the accessibilty
 // tree.
 - (BOOL)accessibilityIsIgnored {
   return [self isIgnored];
 }
 
 // Performs the given accessibilty action on the webkit accessibility object

[David Tseng, 2012/09/13 19:00:57]

If we go with NSAccessibilityIncrementorRole, hook up
NSAccessibilityIncrementAction, NSAccessibilityDecrementAction.

[dmazzoni, 2012/09/13 19:32:29]

Right now that's impossible, there's no way for a screen reader to modify the
value of an ARIA control. The Indie UI proposal will fix this; it will let web
apps listen to high-level actions like "increment", "press", and "jump to last
item" rather than listening to key events. The draft is expected soon and then
we can start implementing it.

 // that backs this object.
 - (void)accessibilityPerformAction:(NSString*)action {
   // TODO(feldstein): Support more actions.
   if ([action isEqualToString:NSAccessibilityPressAction])
     [delegate_ doDefaultAction:browserAccessibility_->renderer_id()];
   else if ([action isEqualToString:NSAccessibilityShowMenuAction])
     [delegate_ performShowMenuAction:self];
 }
 
 // Returns the description of the given action.
@@ skipping 60 matching lines @@
     return [super hash];
   return browserAccessibility_->renderer_id();
 }
 
 - (BOOL)accessibilityShouldUseUniqueId {
   return YES;
 }
 
 @end