//
// Copyright 2006-2007, 2015 Adobe Systems, Incorporated.  All Rights Reserved.
//

/*
@@@BUILDINFO@@@ Geometry.jsx 1.0.0.0
*/
//
// Geometry definitions, based on PMGeometry.h
//

function className( thing )
{
    if ((typeof(thing) == "object") && (typeof(thing.className) != "undefined"))
        return thing.className;
    else
        return typeof(thing);
}

//
// =================================== TPoint ===================================
//

function TPoint( x, y )
{
    this.fX = x;
    this.fY = y;
}

// TPoint Constants
const kTPointOrigion = new TPoint( 0, 0 );
TPoint.kOrigin = kTPointOrigion;

const kTPointInfinite = new TPoint( Infinity, Infinity );
TPoint.kInfinite = kTPointInfinite;

const kTPointClassname = "TPoint";
TPoint.prototype.className = kTPointClassname;

// Overloaded math operators
TPoint.prototype["=="] = function( Src )
{
    return (this.fX == Src.fX) && (this.fY == Src.fY);
}

TPoint.prototype["==="] = function( Src )
{
    return (this.fX === Src.fX) && (this.fY === Src.fY);
}

TPoint.prototype["+"] = function( b )
{
    return new TPoint( this.fX + b.fX, this.fY + b.fY );
}

TPoint.prototype["-"] = function( b, reversed )
{
    if (typeof(b) == "undefined")		// unary minus
        return new TPoint( -this.fX, -this.fY )
    else
    {
        if (reversed)
            return new TPoint( b.fX - this.fX, by.fY - this.fY );
        else
            return new TPoint( this.fX - b.fX, this.fY - b.fY);
    }
}

//
// Multiply and divide work with scalars as well as points
//
TPoint.prototype["*"] = function( b )
{
    if (typeof(b) == 'number')
        return new TPoint( this.fX * b, this.fY * b );
    else
        return new TPoint( this.fX * b.fX, this.fY * b.fY );
}

TPoint.prototype["/"] = function( b, reversed )
{
    if (reversed)
    {
        if (typeof(b) == "number")
            debugger;	// Can't divide a number by a point
        else
            return new TPoint( b.fX / this.fX, b.fY / this.fY );
    }
    else
    {
        if (typeof(b) == 'number')
            return new TPoint( this.fX / b, this.fY / b );
        else
            return new TPoint( this.fX / b.fX, this.fY / b.fY );
    }
}

TPoint.prototype.toString = function()
{
    return "[" + this.fX.toString() + "," + this.fY.toString() + "]";
}

TPoint.prototype.vectorLength = function()
{
    return Math.sqrt( this.fX * this.fX + this.fY * this.fY );
}

TPoint.prototype.distanceTo = function(p)
{
    var delta = this - p;
    return delta.vectorLength();
}

// Return normalized vector
TPoint.prototype.normalize = function()
{
    var vecLen = this.vectorLength();
    if (vecLen == 0.0)
        return new TPoint( 0.0, 0.0 );
    else
        return new TPoint( this.fX / vecLen, this.fY / vecLen );
}

// Return the angle between the vector from the origin to this and the X axis
TPoint.prototype.vectorAngle = function()
{
    var offset = 0.0;

    if (this.fX == 0.0)
    {
        if (this.fY == 0.0)
            return 0.0;
        if (this.fY > 0.0)
            return Math.PI / 2.0;
        else
            return 3 * (Math.PI/2);
    }
    else
    {
        if ((this.fX > 0.0) && (this.fY < 0.0))
            offset = 2*Math.PI;
        else
            if (this.fX < 0.0)
                offset = Math.PI;
        return Math.atan( this.fY / this.fX ) + offset;
    }
}

// Rotate point around angle (in radians) and return the rotated point.
TPoint.prototype.rotate = function( angle )
{
    var ca = Math.cos(angle);
    var sa = Math.sin(angle);

    var nx = this.fX * ca - this.fY * sa;
    var ny = this.fY * ca + this.fX * sa;
    return new TPoint( nx, ny );
}

//
// Test to see if the point is in the quadrilateral (or any convex polygon)
// defined by four points by checking to see if it's on the same side of
// the four edges.  Assumes points are in clockwise (or counterclockwise)
// order.  This is from the classic "10 Algorithms" paper by Sutherland,
// et al.
//
TPoint.prototype.pointInQuad = function( pts )
{
    var i = 0, j;

    var inside = true;
    var whichSide;
    while ((i < pts.length) && inside)
    {
        j = (i == pts.length-1) ? 0 : i + 1;
        var A = (this.fX - pts[j].fX) * (pts[i].fY - pts[j].fY);
        var B = (this.fY - pts[j].fY) * (pts[i].fX - pts[j].fX);

        if (i == 0)
            whichSide = (A > B);
        else
            inside = (whichSide == (A > B));
        i++;
    }
    return inside;
}

// Report what "side" of the line p0, p1 the point is on.
TPoint.prototype.sideOf = function( p0, p1 )
{
    var dist = this.distanceToLine( p0, p1 );
    if (dist == 0.0) return 0;
    if (dist < 0.0) return -1;
    return 1;
}

//
// Compute the distance from "this" to the line defined by p0, p1
//
TPoint.prototype.distanceToLine = function( p0, p1 )
{
    var fBase = p0;
    var fDirection = p1 - p0;

    var other_base = this;
    var other_dir = new TPoint( -fDirection.fY, fDirection.fX );

    // Find point where line perpendicular to p0p1 through this intersects p0p1
    var online = TPoint.lineSegmentIntersect( fBase, fDirection + fBase,
                                                     other_base, other_dir + other_base, false );
    var fromDir = this - online;
    var dist = fromDir.vectorLength();

    // Determine the sign by comparing the vector signs between the
    // point and the line and the line's perpendicular vector.

    if (Math.abs( fromDir.fX ) > Math.abs( fromDir.fY ))
        return (fromDir.fX * fDirection.fY <= 0.0) ? dist : -dist;
    else
        return (fromDir.fY * fDirection.fX > 0.0) ? dist : -dist;
};

// Find where (parametrically) test falls on the
// segment p10 p11.  If it's beyond 0..1, there's no hit
TPoint.prototype.pointInSeg = function( p0, p1 )
{
    // Find two vectors, p0p1 & p0test
    var v0 = p1 - p0;
    var vm = this - p0;

    // Ratio of dot prodcuts gives the projection of vm onto v0
    var t, denom = v0.fX * v0.fX + v0.fY * v0.fY;
    if (denom == 0.0)
        // First line seg zero length...
        return (this == p0);
    else
        t = (v0.fX * vm.fX + v0.fY * vm.fY ) / denom;

    return ((t >= 0.0) && (t <= 1.0));
}


// Class static methods

// Find where line segment (p10 p11) intersects (p20 p21).
// Returns [INF, INF] if no intersection (lines parallel)
TPoint.lineSegmentIntersect = function( p10, p11, p20, p21, checkEndpoints )
{
    var A1, B1, C1, A2, B2, C2;	// Line equations
    var tmp;
    var cross = new TPoint( Infinity, Infinity );

    if (typeof(checkEndpoints) == "undefined")
        checkEndpoints = true;

    // Generate the line equations (Ax+By=C) of the
    // vectors Perpendicular to center->endpoint lines.

    A1 = p10.fY - p11.fY;
    B1 = p11.fX - p10.fX;
    C1 = A1 * p10.fX + B1 * p10.fY;

    A2 = p20.fY - p21.fY;
    B2 = p21.fX - p20.fX;
    C2 = A2 * p20.fX + B2 * p20.fY;

    // Find the intersection of above two lines by solving:
    //	[A1 B1] [x] = [C1]
    //	[A2 B2] [y] = [C2]

    tmp = A1 * B2 - B1 * A2;
    if (tmp == 0.0)		// Parallel
        return cross;
    else
    {
        cross.fX = (B2 * C1 - B1 * C2) / tmp;
        cross.fY = (A1 * C2 - A2 * C1) / tmp;
    }

    if (!checkEndpoints
        || (cross.pointInSeg( p10, p11 ) && cross.pointInSeg( p20, p21 )))
        return cross;
    else
        return new TPoint( Infinity, Infinity );
}

// Clip the line segment defined by p0, p1 to rect (note the segment may be extended
// as well).  Returns false of the line misses the rect

TPoint.clipLineToRect = function( rect, p0, p1 )
{
    var fBase = p0;
    var fDirection = p1 - p0;

    var leftPt, topPt, rightPt, bottomPt;
    var inPts = new Array();
    var incount = 0;

    function evaluateAtX( x )
    {
        if (fDirection.fX == 0.0)	// no Y intercept...
        {
            if (x == fBase.fX)
                return new TPoint( x, Infinity );
            else
                return new TPoint( Infinity, Infinity );
        }
        else
            return new TPoint( x, (fDirection.fY / fDirection.fX) * (x - fBase.fX) + fBase.fY );
    }

    function evaluateAtY( y )
    {
        if (fDirection.fY == 0.0)	// no X intercept...
        {
            if (y == fBase.fY)
                return new TPoint( Infinity, y );
            else
                return new TPoint( Infinity, Infinity );
        }
        else
            return new TPoint( (fDirection.fX / fDirection.fY) * (y - fBase.fY) + fBase.fX, y );
    }

    // If line has no direction, just use the base point
    if (fDirection == TPoint.kOrigin)
    {
        if (rect.contains( fBase ))
        {
            p0 = fBase;
            p1 = fBase;
            return true;
        }
        else
            return true;		// "Line" is outside of rectangle
    }

    // Find the intercepts of the rectangle on the line

    leftPt = evaluateAtX( rect.fLeft );
    if ((leftPt.fY >= rect.fTop) && (leftPt.fY <= rect.fBottom))
        inPts[incount++] = leftPt;

    topPt = evaluateAtY( rect.fTop );
    if ((topPt.fX >= rect.fLeft) && (topPt.fX <= rect.fRight))
        inPts[incount++] = topPt;

    rightPt = evaluateAtX( rect.fRight );
    if ((rightPt.fY >= rect.fTop) && (rightPt.fY <= rect.fBottom))
        inPts[incount++] = rightPt;

    bottomPt = evaluateAtY( rect.fBottom );
    if ((bottomPt.fX >= rect.fLeft) && (bottomPt.fX <= rect.fRight))
        inPts[incount++] = bottomPt;

    if (incount == 0)
        return false;			// Non intersection leaves line unmodified

    $.bp( incount == 1);		// This would be weird...

    p0 = inPts[0];
    if (incount == 2)			// Normal case
        p1 = inPts[1];
    else						// If line hits a corner, find two unique points
    {
        var i;
        for (i = 1; (i < incount) && (inPts[i] == p0); i++) {};
        $.bp( i >= incount );
        p1 = inPts[i];
    }

    return true;
}

// Find the area of a convex polygon.  Always returns
// positive value, so the order (counter/clockwise) doesn't matter.
// From Mathworld: http://mathworld.wolfram.com/PolygonArea.html
TPoint.polygonArea = function( pts )
{
    var i, sum = 0;
    var n = pts.length-1;
    for (i = 0; i < n; ++i)
        sum += pts[i].fX*pts[i+1].fY - pts[i+1].fX * pts[i].fY;
    sum += pts[n].fX*pts[0].fY - pts[0].fX * pts[n].fY;
    return Math.abs(sum) * 0.5;
}

//
// =================================== TRect ===================================
//

function TRect( leftTop, rightBottom )
{
    // Four arguments are assumed to be left top right bottom
    if (arguments.length == 4)
    {
        this.fLeft = arguments[0];
        this.fTop = arguments[1];
        this.fRight = arguments[2];
        this.fBottom = arguments[3];
    }
    else
    // One argument is assumed to be a list of points; the bounds is returned
    if ((arguments.length == 1))
    {
        this.setToBoundsOf( arguments[0] );
    }
    else
    {
        this.fLeft = leftTop.fX;
        this.fTop = leftTop.fY;
        this.fRight = rightBottom.fX;
        this.fBottom = rightBottom.fY;
    }
}

// TRect constants

const kZeroRectData = new TRect( 0, 0, 0, 0 );
TRect.kZeroRect = kZeroRectData;

const kInfiniteRectdata = new TRect( -Infinity, -Infinity, Infinity, Infinity );
TRect.kInfiniteRect = kInfiniteRectdata;

const kRectClassname = "TRect"
TRect.prototype.className = kRectClassname;

// Data access

TRect.prototype.getTopLeft = function()
{
    return new TPoint( this.fLeft, this.fTop );
}

TRect.prototype.getBottomRight = function()
{
    return new TPoint( this.fRight, this.fBottom );
}

TRect.prototype.getBottomLeft = function()
{
    return new TPoint(this.fLeft, this.fBottom);
}

TRect.prototype.getTopRight = function()
{
    return new TPoint(this.fRight, this.fTop);
}

// Return the four corner points of the rectangle as an array of points
TRect.prototype.getCornerPoints = function()
{
    return [this.getTopLeft(), this.getTopRight(), this.getBottomRight(), this.getBottomLeft()];
}

// Returns true if (fRight > fLeft) && (fBottom > fTop)
TRect.prototype.isEmpty = function()
{
    return  (this.fLeft >= this.fRight) || (this.fTop >= this.fBottom);
}

// Returns true if no coordinates are infinite and left/right and top/bottom aren't crossed.
TRect.prototype.isValid = function()
{
    if ((this.fLeft == Infinity) || (this.fRight == Infinity)
        || (this.fTop == Infinity) || (this.fBottom == Infinity))
        return false;

    return (this.fLeft <= this.fRight) && (this.fTop <= this.fBottom);
}

TRect.prototype.getSize = function()
{
    return new TPoint( this.fRight-this.fLeft, this.fBottom-this.fTop );
}

TRect.prototype.getWidth = function()
{
    return this.fRight - this.fLeft;
}

TRect.prototype.getHeight = function()
{
    return this.fBottom-this.fTop;
}

TRect.prototype.getArea = function()
{
    return this.getWidth() * this.getHeight();
}

TRect.prototype.contains = function( geometry )
{
    if (className( geometry ) == "TPoint")	// Check for point
    {
        var p = geometry;
        return ((p.fX >= this.fLeft) &&
                (p.fX < this.fRight) &&
                (p.fY >= this.fTop) &&
                (p.fY < this.fBottom));
    }
    else
    {
        var r = geometry;							// Assume rect instead
        return ((r.fLeft >= this.fLeft) &&
                (r.fRight <= this.fRight) &&
                (r.fTop >= this.fTop) &&
                (r.fBottom <= this.fBottom));
    }
}

// Modifiers

TRect.prototype.setToPoint = function( point )
{
    this.fLeft = point.fX;
    this.fTop = point.fY;
    this.fRight = point.fX;;
    this.fBottom = point.fY;
}

TRect.prototype.setTopLeft = function( point )
{
    this.fLeft = point.fX;
    this.fTop = point.fY;
}

TRect.prototype.setTopRight = function( point )
{
    this.fRight = point.fX;
    this.fTop = point.fY;
}

TRect.prototype.setBottomRight = function( point )
{
    this.fRight = point.fX;;
    this.fBottom = point.fY;
}

TRect.prototype.setBottomLeft = function( point )
{
    this.fLeft = point.fX;;
    this.fBottom = point.fY;
}

TRect.prototype.setSize = function( size )
{
    this.fRight  = this.fLeft + size.fX;
    this.fBottom = this.fTop + size.fY;
}

TRect.prototype.setCenter = function( center )
{
    var delta = center - this.getCenter();
    this.fLeft += delta.fX;
    this.fRight += delta.fX;

    this.fTop += delta.fY;
    this.fBottom += delta.fY;
}

TRect.prototype.setToBoundsOf = function( pointList )
{
    this.fLeft = pointList[0].fX;
    this.fTop = pointList[0].fY;
    this.fRight = this.fLeft;
    this.fBottom = this.fTop;

    var i;
    for (i = 1; i < pointList.length; i++)
        this.extendTo( pointList[i] );
}

// Constructor version of above
TRect.getBounds = function( pointList )
{
    var bounds = new TRect(pointList[0].fX, pointList[0].fY);
    bounds.setToBoundsOf( pointList );
    return bounds;
}

TRect.prototype.extendTo = function( geometry )
{
    // Check incoming geometry for type...
    if (className(geometry) == "TPoint")
    {
        var p = geometry;
        if (p.fX < this.fLeft) this.fLeft = p.fX;
        if (p.fY < this.fTop) this.fTop = p.fY;
        if (p.fX > this.fRight) this.fRight = p.fX;
        if (p.fY > this.fBottom) this.fBottom = p.fY;
    }
    else	// Not point, assume rectangle
    {
        var r = geometry;
        if (this.isEmpty())
        {
            this.fTop = r.fTop;
            this.fLeft = r.fLeft;
            this.fRight = r.fRight;
            this.fBottom = r.fBottom;
        }
        else
        {
            if (! r.isEmpty())
            {
                if (r.fLeft < this.fLeft) this.fLeft = r.fLeft;
                if (r.fTop < this.fTop) this.fTop = r.fTop;
                if (r.fRight > this.fRight) this.fRight = r.fRight;
                if (r.fBottom > this.fBottom) this.fBottom = r.fBottom;
            }
        }
    }
}

TRect.prototype.intersectWith = function( r )
{
    if (this.isEmpty() || r.isEmpty())
    {
        this.fLeft = this.fRight;
        this.fTop = this.fBottom;
    }
    else
    {
        if (r.fLeft > this.fLeft) this.fLeft = r.fLeft;
        if (r.fTop > this.fTop) this.fTop = r.fTop;
        if (r.fRight < this.fRight) this.fRight = r.fRight;
        if (r.fBottom < this.fBottom) this.fBottom = r.fBottom;
        // If the two don't overlap, avoid an invalid rect
        if (this.fRight < this.fLeft)
            this.fLeft = this.fRight;
        if (this.fBottom < this.fTop)
            this.fTop = this.fBottom;
    }
}

// "static" class member.  Returns a new, distinct rectangle.
TRect.intersection = function( a, b )
{
    var x = new TRect( a.fLeft, a.fTop, a.fRight, a.fBottom );
    x.intersectWith( b );
    return x;
}

TRect.prototype.intersects = function( r )
{
    var result;
    if (this.isEmpty())
        result = false;
    else if (r.isEmpty())
        result = false;
    else
        result =  ( (this.fLeft < r.fRight) && (this.fRight > r.fLeft) &&
        (this.fTop < r.fBottom) && (this.fBottom > r.fTop) );
    return result;
}

TRect.prototype.getCenter = function()
{
    return new TPoint( (this.fLeft + this.fRight) * 0.5,
                       (this.fTop + this.fBottom) * 0.5 );
}

TRect.prototype.equalSize = function( r )
{
    return ( ((this.fRight - this.fLeft) == (r.fRight - r.fLeft)) &&
            ((this.fBottom - this.fTop) == (r.fBottom - r.fTop)) );
}

TRect.prototype.offset = function( dg )
{
    this.fLeft += dg.fX;
    this.fTop += dg.fY;
    this.fRight += dg.fX;
    this.fBottom += dg.fY;
}

TRect.prototype.inset = function( inset )
{
    this.fLeft += inset.fX;
    this.fTop += inset.fY;
    this.fRight -= inset.fX;
    this.fBottom -= inset.fY;
}

TRect.prototype.pin = function( pt )
{
    if (this.fLeft > this.fRight) pt.fX = (this.fLeft + this.fRight) / 2;
    else if (pt.fX < this.fLeft) pt.fX = this.fLeft;
    else if (pt.fX > this.fRight) pt.fX = this.fRight;

    if (this.fTop > this.fBottom) pt.fY = (this.fTop + this.fBottom) / 2;
    else if (pt.fY < this.fTop) pt.fY = this.fTop;
    else if (pt.fY > this.fBottom) pt.fY = this.fBottom;
}

// Takes the r's size and position relative to the object's rectangle and
// maps it to the same size and position (proportionally) to the dest
// rectangle.  If the source rectangle has a height or width of zero
// the rectangle r  will have a corresponding infinite height or width.
TRect.prototype.mapRect = function( r, dest )
{
    var victLT = new TPoint( r.fLeft, r.fTop );
    var victRB = new TPoint( r.fRight, r.fBottom );
    var srcLT = new TPoint( this.fLeft, this.fTop );
    var srcRB = new TPoint( this.fRight, this.fBottom );
    var destLT = new TPoint( dest.fLeft, dest.fTop );
    var destRB = new TPoint( dest.fRight, dest.fBottom );

    victLT -= srcLT;
    victRB -= srcLT;

    // bk bug fix - we need to use floating, rather than integer, arithmetic for scaling to work correctly.
//	TPoint scale = (destRB - destLT) / (srcRB - srcLT);
//	victLT *= scale;
//	victRB *= scale;

    var x_scale = (destRB.fX - destLT.fX) / (srcRB.fX - srcLT.fX);
    var y_scale = (destRB.fY - destLT.fY) / (srcRB.fY - srcLT.fY);
    victLT.fX = (victLT.fX * x_scale);
    victLT.fY = (victLT.fY * y_scale);
    victRB.fX = (victRB.fX * x_scale);
    victRB.fY = (victRB.fY * y_scale);

    victLT += destLT;
    victRB += destLT;

    return new TRect( victLT, victRB );
}

TRect.prototype.mapPoint = function( pt, dest )
{
    var srcLT = new TPoint( this.fLeft, this.fTop );
    var srcRB = new TPoint( this.fRight, this.fBottom );
    var destLT = new TPoint( dest.fLeft, dest.fTop );
    var destRB = new TPoint( dest.fRight, dest.fBottom );

    pt -= srcLT;

    var x_scale = (destRB.fX - destLT.fX) / (srcRB.fX - srcLT.fX);
    var y_scale = (destRB.fY - destLT.fY) / (srcRB.fY - srcLT.fY);
    pt.fX = (pt.fX * x_scale);
    pt.fY = (pt.fY * y_scale);

    pt += destLT;
    return pt;
}

TRect.prototype.orderPoints = function()
{
    if (this.fLeft > this.fRight)
    {
        var tmp = this.fRight;
        this.fRight = this.fLeft;
        this.fLeft = tmp;
    }
    if (this.fTop > this.fBottom)
    {
        var tmp = this.fTop;
        this.fTop = this.fBottom;
        this.fBottom = tmp;
    }
}

TRect.prototype["=="] = function( src )
{
    if (this.fLeft != src.fLeft) return false;
    if (this.fTop != src.fTop) return false;
    if (this.fRight != src.fRight) return false;
    if (this.fBottom != src.fBottom) return false;
    return true;
}

TRect.prototype.toString = function()
{
    return "[" + this.fLeft.toString() + "," + this.fTop.toString()
        + "," + this.fRight.toString() + "," + this.fBottom.toString() + "]";
}

//
// Rectangle to rectangle clip, specialized for the
// crop case of removing the image rect from the crop rect,
// leaving behind the portions to be filled.
//
// OK, imagine 'minus' is completely inside of 'this'.  That
// leaves eight possible leftover rectangle pieces; fewer
// if minus is not completely contained.  We find these rects,
// (called "tiles" here) and coalesce them together as possible.
// For example, if minus is taller (both above & below) thisRect,
// then only rects 0,3,5 and 2,4,7 are left over.
//
// +---+---------+---+
// | 0 |    1    | 2 |
// +---+---------+---+
// | 3 |  minus  | 4 |
// +---+---------+---+
// | 5 |    6    | 7 |
// +---+---------+---+
//
// AdobePatentID="P5923-US"
TRect.prototype.subtract = function( minus )
{
    if (minus.contains( this ) || !minus.intersects( this ))
        return null;

    var self = this;

    var topLT    = this.fTop    < minus.fTop;
    var leftLT   = this.fLeft   < minus.fLeft;
    var rightGT  = this.fRight  > minus.fRight;
    var bottomGT = this.fBottom > minus.fBottom;

    // Figure out which tiles are visible
    var tileState = [leftLT && topLT,     topLT,   rightGT && topLT,     // 0, 1, 2
                     leftLT,                       rightGT,              // 3     4
                     leftLT && bottomGT, bottomGT, rightGT && bottomGT]; // 5, 6, 7

    var tileUsed = [false, false, false, false, false, false, false, false];
    var resultRects = [];

    // If a corner tile next to a side tile is visible, expand
    // tileRect to include it.
    function extendRect( tileRect, tileNum, side )
    {
        if (tileState[tileNum] && !tileUsed[tileNum])
        {
            tileUsed[tileNum] = true;
            tileRect[side] = self[side];
        }
    }

    // Check each of the "side" tiles, (1, 3, 4, 6).  For each one,
    // see if the adjacent tile is also included, and has not been
    // used yet.  If so, expand the returned rect for that side tile
    // to include the neighbor.
    function makeAndExpandSide( sideNum, thisSide, thisDst,
                                c1Num, c1Side, c2Num, c2Side )
    {
        if (tileState[sideNum])
        {
            tileUsed[sideNum] = true;
            var newTile = new TRect( minus.fLeft, minus.fTop,
                                     minus.fRight, minus.fBottom );
            newTile[thisSide] = self[thisSide];
            newTile[thisDst] = minus[thisSide];
            // If either the c1 or c2 side isn't included, then
            // shrink the new tile to this's corresponding side
            if (! tileState[c1Num]) newTile[c1Side] = self[c1Side];
            if (! tileState[c2Num]) newTile[c2Side] = self[c2Side];
            extendRect( newTile, c1Num, c1Side );
            extendRect( newTile, c2Num, c2Side );
            resultRects.push( newTile );
        }
    }

    // Walk around the edges, collecting and coalescing all the tiles we find.
    makeAndExpandSide( 1, "fTop", "fBottom", 0, "fLeft",  2, "fRight" );
    makeAndExpandSide( 3, "fLeft", "fRight", 0, "fTop",   5, "fBottom" );
    makeAndExpandSide( 4, "fRight", "fLeft", 2, "fTop",   7, "fBottom" );
    makeAndExpandSide( 6, "fBottom", "fTop", 5, "fLeft",  7, "fRight" );

    return resultRects;
};

// DEBUG
//aa = new TPoint(2,3);
//bb = new TPoint(7,7);
//r = new TRect(0,0,2,2);

//t0 = new TPoint(2,7);
//t1 = new TPoint(6,3);
//p0 = new TPoint(2,3);
//p1 = new TPoint(6,7);