//  NSString_Wrapping.m

//  TipWrapper

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

//  See legal notice at end of file.

#import "NSString_Wrapping.h"

#import "NSTextView_Lines.h"

@implementation NSString (Wrapping)

#pragma mark PRIVATE CLASS METHODS

//  This code is not thread-safe. In a multi-threaded application, one would need to cache

//  a separate text-view in each thread, perhaps using the current threadÕs -threadDictionary/

+ (NSTextView *) sharedTextViewForWrappingForToolTips

{

    static NSTextView   *sharedTextView = nil;

    if (sharedTextView == nil)

    {

        //  The initial frame doesnÕt matter.

        sharedTextView = [[NSTextView alloc] initWithFrame: NSMakeRect (0, 0, 10, 10)];

        //  We're going to measure things with a single font

        [sharedTextView setRichText: NO];

        //  Make the size flex vertically (not sure we need this)

        [sharedTextView setHorizontallyResizable: NO];

        [sharedTextView setVerticallyResizable: YES];

        //  We want padding which looks (about?) like a tool-tipÕs padding.

        //  No need to change the -textContainerInset, which is already zero,

        //  but we do need to reduce the lineÕs padding to look like a tool tip.

        [[sharedTextView textContainer] setLineFragmentPadding: 0];

        //  Not sure we need to set these

        [sharedTextView setMinSize: NSMakeSize (0, 0)];

        [sharedTextView setMaxSize: NSMakeSize (9999, 9999)];

        //  Use the default tool-tip font

        [sharedTextView setFont: [NSFont toolTipsFontOfSize: 0.0]];

    }

    return sharedTextView;

}

#pragma mark PUBLIC INSTANCE METHODS

//  Return the receiving string, with newlines added to wrap it to the specified width in pixels.

//  We do this by setting a text-view to the width we want, stuffing the text in, letting

//  the text-view wrap it for us, then finding out where the text-view wrapped the string,

//  and inserting newlines at those wrap-places to force the string to wrap when displayed

//  in any context.

- (NSString *) stringWrappedForToolTipToPixelWidth: (unsigned int) width

{

    NSTextView      *tv;

    NSRect          frame;

    NSArray         *lines;

    //  Set the shared text-view to have the width we want

    tv = [[self class] sharedTextViewForWrappingForToolTips];

    frame = [tv frame];

    frame.size.width = width;

    [tv setFrame: frame];

    //  Load us as its content

    [tv setString: self];

    [tv setLineSpacingTo: 1];           // this seems to make the text lay out like tool-tips do

    //  Get the individual lines as laid out by the text-view with (soft or hard) newlines.

    lines = [tv lines];

    //  Ditch the text-view's contents, to avoid wasting memory.

    [tv setString: @""];

    //  Return a single string with hard newlines in all the places where the text-view broke it

    return [lines componentsJoinedByString: @"\n"];

}

//  Return the receiving string, with newlines inserted to wrap it to a width which

//  produces the specified number of lines. We do this with a binary search, trying

//  to find the pixel width which gives us the desired line count.

- (NSString *) stringWrappedForToolTipToLineCount: (unsigned int) desiredLineCount

{

    NSTextView      *tv;

    NSRect          frame;

    //  INVARIANT:  minPixelWidth < maxPixelWidth

    //  We could be smarter here, and start 'maxPixelWidth' as the measured length of the unwrapped string.

    unsigned int    minPixelWidth = 1,

                    maxPixelWidth = 10000; // view coordinates canÕt exceed this value

    //  INVARIANT:  lineCountForMinPixelWidth >= desiredLineCount >= lineCountForMaxPixelWidth

    //              unless theyÕre -1

    int             lineCountForMinPixelWidth = -1, lineCountForMaxPixelWidth = -1;

    //  Get the shared text-view

    tv = [[self class] sharedTextViewForWrappingForToolTips];

    frame = [tv frame];

    //  Load us as its content

    [tv setString: self];

    [tv setLineSpacingTo: 1];           // this seems to make the text lay out like tool-tips do

    //  Loop until the binary search converges, to find the pixel width which

    //  gives us the right line count.

    while (minPixelWidth < (maxPixelWidth-1))

    {

        int     newPixelWidth, newLineCount;

        //  Handle the case with no known min or max pixel width

        if ((lineCountForMinPixelWidth == -1) && (lineCountForMaxPixelWidth == -1))

        {

            NSSize  stringSize;

            //  We have no information so far. Estimate the initial width from the string's total

            //  width divided by the desired number of lines.

            //  We use NSStringÕs -sizeWithAttributes: instead of NSFontÕs widthOfString:,

            //  which documentation says is deprecated.

            stringSize = [self sizeWithAttributes: [NSDictionary dictionaryWithObject: [tv font]

                                                    forKey: NSFontAttributeName]];

            newPixelWidth = stringSize.width / desiredLineCount;

        }

        //  Handle the case with no known max pixel width

        else if (lineCountForMaxPixelWidth == -1)

        {

            //  Try to approximate the correct pixel width from a single datum, the min

            //  Assume that

            //      (lines1*width1 == lines2*width2)

            //  so approximately:

            //      width1 = width2 * (lines2 / lines1)

            newPixelWidth = minPixelWidth * ((float)lineCountForMinPixelWidth / desiredLineCount);

        }

        //  Handle the case with no known min pixel width

        else if (lineCountForMinPixelWidth == -1)

        {

            //  Try to approximate the correct pixel width from a single datum, the max,

            //  much like above.

            newPixelWidth = maxPixelWidth * ((float)lineCountForMaxPixelWidth / desiredLineCount);

        }

        //  Handle the case with known min AND max pixel width

        else

        {

            float   newPixelWidthMax, newPixelWidthMin;

            newPixelWidthMin = minPixelWidth * ((float)lineCountForMinPixelWidth / desiredLineCount);

            newPixelWidthMax = maxPixelWidth * ((float)lineCountForMaxPixelWidth / desiredLineCount);

            //  We have both min and max; take the mean of the two approximations for the next guess

            //  (Perhaps a geometric mean would make it converge more rapidly?)

            newPixelWidth = (newPixelWidthMin + newPixelWidthMax) / 2;

        }

        //  Sanity check: Make sure the new pixel width is between the old min and max

        if (newPixelWidth <= minPixelWidth)

            newPixelWidth = (minPixelWidth+1);

        else if (newPixelWidth >= maxPixelWidth)

            newPixelWidth = (maxPixelWidth-1);

        //  Size the text-view to the new width, and see how many lines we get.

        frame.size.width = newPixelWidth;

        [tv setFrame: frame];

        newLineCount = [tv numberOfLines];

        if (newLineCount <= desiredLineCount)   // too few lines?

        {

            maxPixelWidth = newPixelWidth;  // too few lines: squeeze in

            lineCountForMaxPixelWidth = newLineCount;

        }

        else                            // too many lines?

        {

            minPixelWidth = newPixelWidth;  // too many lines: open up wider

            lineCountForMinPixelWidth = newLineCount;

        }

    }

    //  Adjust the width one last time

    frame.size.width = maxPixelWidth;

    [tv setFrame: frame];

    {

        NSArray     *lines = [tv lines];

        //  Ditch the text-view's contents, to avoid wasting memory.

        [tv setString: @""];

        //  Return a single string with hard newlines in all the places where the text-view broke it

        return [lines componentsJoinedByString: @"\n"];

    }

}

//  Return the receiver with newlines inserted to wrap it to a width which produces the

//  specified width-to-height ratio.

- (NSString *) stringWrappedForToolTipToWidthToHeightRatio: (float) desiredRatio

{

    NSTextView      *tv;

    NSRect          frame;

    int             minPixelWidth, maxPixelWidth;

    //  Get the shared text-view

    tv = [[self class] sharedTextViewForWrappingForToolTips];

    frame = [tv frame];

    //  Load us as its content

    [tv setString: self];

    [tv setLineSpacingTo: 1];           // this seems to make the text lay out like tool-tips do

    minPixelWidth = 10;

    //  We could be smarter here, and start 'maxPixelWidth' as the measured length of the unwrapped string.

    maxPixelWidth = 10000;              // AppKit limit: view coordinates canÕt exceed 10,000

    //  Loop until the binary search converges, to find the pixel width which comes

    //  closest to the desired width-to-height ratio.

    while (minPixelWidth < (maxPixelWidth-1))

    {

        int     newPixelWidth;

        //  Take the mean of the two widths.

        //  (Perhaps a geometric mean would make it converge more rapidly?)

        newPixelWidth = (minPixelWidth + maxPixelWidth) / 2;

        //  Make sure we're trying a new value

        if (newPixelWidth == minPixelWidth) ++newPixelWidth;

        else if (newPixelWidth == maxPixelWidth) --newPixelWidth;

        frame.size.width = newPixelWidth;

        [tv setFrame: frame];

        //  Update the text-viewÕs height to fit the text (we did setVerticallyResizable:YES earlier)

        [tv sizeToFit];

        frame = [tv frame];

        if (frame.size.height == 0)     // too wide? (not sure we need this check)

            maxPixelWidth = newPixelWidth;  // too wide: squeeze in

        else

        {

            float   newRatio;

            newRatio = (frame.size.width / frame.size.height);

            if (newRatio < desiredRatio)

                minPixelWidth = newPixelWidth; // open up wider

            else

                maxPixelWidth = newPixelWidth; // narrower

        }

    }

    //  Adjust the width one last time

    frame.size.width = maxPixelWidth;

    [tv setFrame: frame];

    //  Return a single string with hard newlines in all the places where the text-view broke it

    return [[tv lines] componentsJoinedByString: @"\n"];

}

@end

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