Wrong clipping at a right angle

[codenia]

Hi Adam,

If I have a right angle on both paths, in some positions the path is not being split correctly.

At first I have a working example.

Path to be split:

UIBezierPath *tilePath = [UIBezierPath bezierPath];
[tilePath moveToPoint:CGPointMake(2943, 228)];
[tilePath addLineToPoint:CGPointMake(3189, 228)];
[tilePath addLineToPoint:CGPointMake(3189, 892)];
[tilePath addLineToPoint:CGPointMake(2943, 892)];
[tilePath closePath];

Path to do the slice:

UIBezierPath *areaPath = [UIBezierPath bezierPath];
[areaPath moveToPoint:CGPointMake(0, 0)];           
[areaPath addLineToPoint:CGPointMake(0, 1310)];
[areaPath addLineToPoint:CGPointMake(550, 1310)];
[areaPath addLineToPoint:CGPointMake(1490, 2240)];
[areaPath addLineToPoint:CGPointMake(1490, 2790)];
[areaPath addLineToPoint:CGPointMake(2810, 2790)];
[areaPath addLineToPoint:CGPointMake(2810, 2545)];
[areaPath addLineToPoint:CGPointMake(4190, 2545)];
[areaPath addLineToPoint:CGPointMake(4190, 890)];
[areaPath addLineToPoint:CGPointMake(3140, 890)];
[areaPath addLineToPoint:CGPointMake(3140, 0)];
[areaPath closePath];

After calling the uniqueShapesCreatedFromSlicingWithUnclosedPath I get two shapes.

NSArray* shapes = [tilePath uniqueShapesCreatedFromSlicingWithUnclosedPath:areaPath];
if(shapes.count == 2)
{
    // It's perfect ;-)
}

Everything's okay here:

Now the case that doesn't work properly:

I move the tile one pixel/unit down:

UIBezierPath *tilePath = [UIBezierPath bezierPath];
[tilePath moveToPoint:CGPointMake(2943, 227)];
[tilePath addLineToPoint:CGPointMake(3189, 227)];
[tilePath addLineToPoint:CGPointMake(3189, 891)];
[tilePath addLineToPoint:CGPointMake(2943, 891)];
[tilePath closePath];

Now after calling the uniqueShapesCreatedFromSlicingWithUnclosedPath I only get one shape.

NSArray* shapes = [tilePath uniqueShapesCreatedFromSlicingWithUnclosedPath:areaPath];
if(shapes.count == 1)
{
    // It's not perfect ;-(
}

Now a part of the tile is missing: