ImageMapAccessibility.m

/*
 
File: ImageMapAccessibility.m
 
Abstract: accessibility code for image map widget
 
Version: <1.0>
 
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*/ 
 
#import "ImageMapPrivate.h"
#import "FauxUIElement.h"
 
#import <AppKit/NSAccessibility.h>
 
 
@interface  HotSpotUIElement : FauxUIElement {
    int index;
}
- (id)initWithIndex:(int)anIndex parent:(id)aParent;
+ (HotSpotUIElement *)elementWithIndex:(int)anIndex parent:(id)aParent;
- (int)index;
@end
 
 
@implementation HotSpotUIElement
 
- (id)initWithIndex:(int)anIndex parent:(id)aParent {
    if (self = [super initWithRole:NSAccessibilityButtonRole parent:aParent]) {
        index = anIndex;
    }
    return self;
}
 
+ (HotSpotUIElement *)elementWithIndex:(int)anIndex parent:(id)aParent {
    return [[[HotSpotUIElement alloc] initWithIndex:anIndex parent:aParent] autorelease];
}
 
- (BOOL)isEqual:(id)object {
    if ([object isKindOfClass:[HotSpotUIElement self]]) {
        HotSpotUIElement *other = object;
        return (index == other->index) && [super isEqual:object];
    } else {
        return NO;
    }
}
 
- (unsigned)hash {
    // Equal objects must hash the same.
    return [super hash] + index;
}
 
- (int)index {
    return index;
}
 
- (NSArray *)accessibilityAttributeNames {
    ImageMap *imageMap = parent;
    if ([imageMap isHTMLImageMap]) {
    // For HTML image maps we can provide a description using the alt or title attributes.
    static NSArray *attributes = nil;
    if (attributes == nil) {
        attributes = [[[super accessibilityAttributeNames] arrayByAddingObject:NSAccessibilityDescriptionAttribute] retain];
    }
    return attributes;
    } else {
    return [super accessibilityAttributeNames];
    }
}
 
- (id)accessibilityAttributeValue:(NSString *)attribute {
    if ([attribute isEqualToString:NSAccessibilityDescriptionAttribute]) {
    ImageMap *imageMap = parent;
    NSDictionary *info = [imageMap infoForHotSpotAtIndex:index];
    NSString *description = [info valueForKey:@"alt"];
    if (description == nil) {
        description = [info valueForKey:@"title"];
    }
    return description;
    } else if ([attribute isEqualToString:NSAccessibilityEnabledAttribute]) {
    return [NSNumber numberWithBool:YES];
    } else {
    return [super accessibilityAttributeValue:attribute];
    }
}
 
- (NSArray *)accessibilityActionNames {
    return [NSArray arrayWithObject:NSAccessibilityPressAction];
}
 
- (NSString *)accessibilityActionDescription:(NSString *)action {
    return NSAccessibilityActionDescription(action);
}
 
- (void)accessibilityPerformAction:(NSString *)action {
    ImageMap *imageMap = parent;
    [imageMap performActionForHotSpotAtIndex:index];
}
 
@end
 
 
@implementation ImageMap (ImageMapAccessibility)
 
- (BOOL)accessibilityIsIgnored {
    return NO;
}
 
- (id)accessibilityAttributeValue:(NSString *)attribute {
    if ([attribute isEqualToString:NSAccessibilityRoleAttribute]) {
    return NSAccessibilityGroupRole;
    } else if ([attribute isEqualToString:NSAccessibilityRoleDescriptionAttribute]) {
    return NSAccessibilityRoleDescriptionForUIElement(self);
    } else if ([attribute isEqualToString:NSAccessibilityChildrenAttribute]) {
    int numHotSpots = [self numHotSpots];
    NSMutableArray *kids = [NSMutableArray arrayWithCapacity:numHotSpots];
    int i;
    for (i = 0; i < numHotSpots; ++i) {
        [kids addObject:[HotSpotUIElement elementWithIndex:i parent:self]];
    }
    
    // Handle the default as a giant hot spot - for accessibility purposes.
    if ([self hasDefault]) {
        [kids addObject:[HotSpotUIElement elementWithIndex:NSNotFound parent:self]];
    }
    
    return NSAccessibilityUnignoredChildren(kids);
    } else {
    return [super accessibilityAttributeValue:attribute];
    }
}
 
- (id)accessibilityHitTest:(NSPoint)point {
    NSPoint windowPoint = [[self window] convertScreenToBase:point];
    NSPoint localPoint = [self convertPoint:windowPoint fromView:nil];
    int index = [self hotSpotIndexForPoint:localPoint];
    if (index != NSNotFound || [self hasDefault]) {
    // Handle the default as a giant hot spot - for accessibility purposes.
    HotSpotUIElement *hotSpot = [HotSpotUIElement elementWithIndex:index parent:self];
    // Allow the hot spot to do further hit testing.
    return [hotSpot accessibilityHitTest:point];
    } else {
    return [super accessibilityHitTest:point];
    }
}
 
 
//
// FauxUIElementChildSupport protocol
//
 
- (BOOL)isFauxUIElementFocusable:(FauxUIElement *)fauxElement {
    // Always NO - unless we add keyboard focus support to image map.
    return NO;
}
 
- (void)fauxUIElement:(FauxUIElement *)fauxElement setFocus:(id)value {
    // Never called - unless we add keyboard focus support to image map.
}
 
- (NSPoint)fauxUIElementPosition:(FauxUIElement *)fauxElement {
    HotSpotUIElement *hotSpot = (HotSpotUIElement *)fauxElement;
    int index = [hotSpot index];
    NSPoint windowPoint;
    if (index != NSNotFound) {
    NSRect localBounds = [self boundsForHotSpotAtIndex:index];
    NSPoint localPoint = localBounds.origin;
    if ([self isFlipped]) {
        localPoint.y += localBounds.size.height;
    }
    windowPoint = [self convertPoint:localPoint toView:nil];
    } else {
    // Handle the default as a giant hot spot - for accessibility purposes.
    windowPoint = [self frame].origin;
    }
    return [[self window] convertBaseToScreen:windowPoint];
}
 
- (NSSize)fauxUIElementSize:(FauxUIElement *)fauxElement {
    HotSpotUIElement *hotSpot = (HotSpotUIElement *)fauxElement;
    int index = [hotSpot index];
    if (index != NSNotFound) {
    NSRect localBounds = [self boundsForHotSpotAtIndex:index];
    return [self convertSize:localBounds.size toView:nil];
    } else {
    // Handle the default as a giant hot spot - for accessibility purposes.
    return [self frame].size;
    }
}
 
@end