| how to determine whether a line segment intersects [message #187604] |
Wed, 13 July 2005 20:00  |
Eclipse User |
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Originally posted by: bencomo.us.ibm.com
Randy / Pratik / GEF Jedi Masters:
In my subclass of ChopboxAnchor, I have overridden the getLocation method
to check if the line segment intersects the TextFlow's bounds. However,
PointList#intersects(Rectangle) is not returns false when the line segment
intersects. Please let me know if you see what I am missing.
Thank you in advance,
Al.-
public Point getLocation(Point reference)
{
Rectangle textRect = null;
PointList pointList = new PointList();
textRect = taskFigure.getLabel().getBounds().getCopy();
taskFigure.getLabel().translateToAbsolute(textRect);
Rectangle r = Rectangle.SINGLETON;
r.setBounds(getBox());
r.translate(-1, -1);
r.resize(1, 1);
getOwner().translateToAbsolute(r);
float centerX = r.x + 0.5f * r.width;
float centerY = r.y + 0.5f * r.height;
if (r.isEmpty() || (reference.x == (int) centerX && reference.y ==
(int) centerY))
return new Point((int) centerX, (int) centerY);
float dx = reference.x - centerX;
float dy = reference.y - centerY;
float scale = 0.5f / Math.max(Math.abs(dx) / r.width, Math.abs(dy) /
r.height);
dx *= scale;
dy *= scale;
centerX += dx;
centerY += dy;
Point linkPoint = new Point(Math.round(centerX), Math.round(centerY));
pointList.addPoint(linkPoint);
if (pointList.intersects(textRect))
{
// I am not doing anyhting here yet...
// I just want to check if intersects() returns true
return linkPoint; // Apply offset before return it..
}
return linkPoint;
}
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| Re: how to determine whether a line segment intersects [message #187613 is a reply to message #187604] |
Wed, 13 July 2005 22:58  |
| Eclipse User |
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Originally posted by: none.unknown.com
Did you try debugging at all to see what's happening? Your code is
needlessly complicated. You don't need to copy anything from the super
method, you can just call super when needed (which, by the way, you don't
need to do if you just want to see if the line segment is intersecting the
text).
As for the problem, I only see you adding one point to the PointList.
"Al Bencomo" <bencomo@us.ibm.com> wrote in message
news:cc6bb09211b2b8a1030041591c445c53$1@www.eclipse.org...
> Randy / Pratik / GEF Jedi Masters:
>
> In my subclass of ChopboxAnchor, I have overridden the getLocation method
> to check if the line segment intersects the TextFlow's bounds. However,
> PointList#intersects(Rectangle) is not returns false when the line segment
> intersects. Please let me know if you see what I am missing.
>
> Thank you in advance,
> Al.-
>
> public Point getLocation(Point reference)
> {
> Rectangle textRect = null;
> PointList pointList = new PointList();
>
> textRect = taskFigure.getLabel().getBounds().getCopy();
> taskFigure.getLabel().translateToAbsolute(textRect);
>
> Rectangle r = Rectangle.SINGLETON;
> r.setBounds(getBox());
> r.translate(-1, -1);
> r.resize(1, 1);
>
> getOwner().translateToAbsolute(r);
>
> float centerX = r.x + 0.5f * r.width;
> float centerY = r.y + 0.5f * r.height;
>
> if (r.isEmpty() || (reference.x == (int) centerX && reference.y ==
> (int) centerY))
> return new Point((int) centerX, (int) centerY);
>
> float dx = reference.x - centerX;
> float dy = reference.y - centerY;
>
> float scale = 0.5f / Math.max(Math.abs(dx) / r.width, Math.abs(dy) /
> r.height);
>
> dx *= scale;
> dy *= scale;
> centerX += dx;
> centerY += dy;
>
> Point linkPoint = new Point(Math.round(centerX), Math.round(centerY));
>
> pointList.addPoint(linkPoint);
>
> if (pointList.intersects(textRect))
> {
> // I am not doing anyhting here yet...
> // I just want to check if intersects() returns true
> return linkPoint; // Apply offset before return it..
> }
> return linkPoint;
> }
>
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