//  NSTextViewWithLinks.m

//  TextLinks

//  Copyright (c) 2003 Apple Computer, Inc. All rights reserved.

//  See legal notice at end of file.

//  This application demonstrates how to programmatically create links in text,

//  and optionally handle clicks in those links. See README.rtf for more information.

#import "NSTextViewWithLinks.h"

//  Informal protocol for extending NSTextView's delegate

@interface NSObject (NSTextViewWithLinks_Delegate)

- (NSCursor *) cursorForLink: (NSObject *) linkObject

    atIndex: (unsigned) charIndex

    ofTextView: (NSTextView *) aTextView;

@end

@implementation NSTextViewWithLinks

#pragma mark PRIVATE CLASS METHODS

+ (NSCursor *) fingerCursor;            // really should be in a category on NSCursor

{

    static NSCursor *fingerCursor = nil;

    if (fingerCursor == nil)

    {

        fingerCursor = [[NSCursor alloc] initWithImage: [NSImage imageNamed: @"fingerCursor"]

            hotSpot: NSMakePoint (0, 0)];

    }

    return fingerCursor;

}

#pragma mark PUBLIC CLASS METHODS -- NSObject OVERRIDES

//  Make all NSTextView instances into instances of this class, even if we didn't create them.

//  (We could instead selectively make some instances in nib files belong to this class,

//   but then it's hard to enter the initial text using Interface Builder.)

+ (void) load

{

    [self poseAsClass: [self superclass]];

}

#pragma mark PRIVATE INSTANCE METHODS

- (NSCursor *) cursorForLink: (NSObject *) linkObject

    atIndex: (unsigned) charIndex

{

    NSCursor    *result = nil;

    //  If the delegate implements the method, consult it.

    if ([[self delegate] respondsToSelector: @selector(cursorForLink:atIndex:ofTextView:)])

        result = [[self delegate] cursorForLink: linkObject  atIndex: charIndex  ofTextView: self];

    //  If the delegate didn't implement it, or it did but returned nil, substitute a guess.

    if (result == nil)

        result = [[self class] fingerCursor];

    return result;

}

#pragma mark PUBLIC INSTANCE METHODS -- NSView OVERRIDES

- (void) resetCursorRects

{

    NSAttributedString  *attrString;

    NSPoint             containerOrigin;

    NSRect              visRect;

    NSRange             visibleGlyphRange, visibleCharRange, attrsRange;

    //  Get the attributed text inside us

    attrString = [self textStorage];

    //  Figure what part of us is visible (we're typically inside a scrollview)

    containerOrigin = [self textContainerOrigin];

    visRect = NSOffsetRect ([self visibleRect], -containerOrigin.x, -containerOrigin.y);

    //  Figure the range of characters which is visible

    visibleGlyphRange = [[self layoutManager] glyphRangeForBoundingRect:visRect inTextContainer:[self textContainer]];

    visibleCharRange = [[self layoutManager] characterRangeForGlyphRange:visibleGlyphRange actualGlyphRange:NULL];

    //  Prime for the loop

    attrsRange = NSMakeRange (visibleCharRange.location, 0);

    //  Loop until we reach the end of the visible range of characters

    while (NSMaxRange(attrsRange) < NSMaxRange(visibleCharRange)) // find all visible URLs and set up cursor rects

    {

        NSString *linkObject;

        //  Find the next link inside the range

        linkObject = [attrString attribute: NSLinkAttributeName 

            atIndex: NSMaxRange(attrsRange)

            effectiveRange: &attrsRange];

        if (linkObject != nil)

        {

            NSCursor        *cursor;

            NSRectArray     rects;

            unsigned int    rectCount, rectIndex;

            NSRect          oneRect;

            //  Figure what cursor to show over this link.

            cursor = [self cursorForLink: linkObject  atIndex: attrsRange.location];

            //  Find the rectangles where this range falls. (We could use -boundingRectForGlyphRange:...,

            //  but that gives a single rectangle, which might be overly large when a link runs

            //  through more than one line.)

            rects = [[self layoutManager] rectArrayForCharacterRange: attrsRange

                withinSelectedCharacterRange: NSMakeRange (NSNotFound, 0)

                inTextContainer: [self textContainer]

                rectCount: &rectCount];

            //  For each rectangle, find its visible portion and ask for the cursor to appear

            //  when they're over that rectangle.

            for (rectIndex = 0; rectIndex < rectCount; rectIndex++)

            {

                oneRect = NSIntersectionRect (rects[rectIndex], [self visibleRect]);

                [self addCursorRect: oneRect  cursor: cursor];

            }

       }

    }

}

@end

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