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NSBezierPath containsPoint is buggy?

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NSBezierPath containsPoint is buggy?

Subject: NSBezierPath containsPoint is buggy?
From: "Brian O'Brien" <email@hidden>
Date: Mon, 16 Jan 2006 16:23:55 -0700

I have written an application that draws shapes on the screen. The application then needs to know if a point is inside one of these shapes. However my log shows that there is a problem with the NSBezierPath containsPoint method.

Here is the code more or less:
(I haven't shown the affine transform code to keep things simple..)

int fround(float x)
{
	if (x < 0.0)
		return((int) (x - 0.5f));
	return((int) (x + 0.5f));
}

- (IBAction)doIt:(id)sender
{
	int x, y, x1, y1, x2, y2, w, h;
	NSRect r;
	NSRect pathBounds;
	NSPoint pt;

    r.origin.x = 100.0f;
    r.origin.y = 100.0f;
    r.size.width = 40.0f;
    r.size.height = 40.0f;

	NSBezierPath *p = [NSBezierPath bezierPathWithOvalInRect:r];
	pathBounds = [p bounds];

printf("The paths bounding box is ((%f,%f), (%f, %f))\n", pathBounds.origin.x, pathBounds.origin.y, pathBounds.size.width, pathBounds.size.height);

	x1 = fround(pathBounds.origin.x);
	y1 = fround(pathBounds.origin.y);
	w =  fround(pathBounds.size.width);
	h =  fround(pathBounds.size.height);

x2 = x1 + w + 1; y2 = y1 + h + 1; printf("The paths integer bounding box is ((%d,%d), (%d,%d))\n", x1, y1, w, h);


    printf("The bounds are ((%d,%d), (%d,%d))\n", x1, y1, x2, y2);
	for (y=y1; y < y2; ++y)
	{
		for (x=x1; x < x2; ++x)
		{
			pt.x = (float)x;
			pt.y = (float)y;
			if ([p containsPoint:pt])
				printf("#");
			else
				printf("-");
		}
		printf("\n");
	}
}

Here is a log of one of an oval that has been slightly rotated.... there are holes..

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - # <--- Definitely wrong - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # # # # # # - - - - - - - - - - - - - - - - - - - - - - - - - - - # # # # # # # # # # # # # # # # - - - - - - - - -

I think that this demonstrates that there is a bug in the interior test of the bezier curve. Can anyone else duplicate this problem and/or have a workaround?

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Re: NSBezierPath containsPoint is buggy?
From: "Brian O'Brien" <email@hidden>


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