rectangle contains point
 

So, I have a rectangle class as follows:

public class My_Rectangle {
double x, y, width, height;
AffineTransform aft;

Anyone know a good strategy for checking if a point is in the rectangle?

The main difficulty is the transform.

Re: rectangle contains point
 

On 10/5/2012 12:00 PM, bob smith wrote:
> So, I have a rectangle class as follows:
>
> public class My_Rectangle {
> double x, y, width, height;
> AffineTransform aft;
>
> Anyone know a good strategy for checking if a point is in the rectangle?
>
> The main difficulty is the transform.


http://lmgtfy.com/?q=computational+geometery

Seriously, it's a big subject. I don't have any easy answers.

Re: rectangle contains point
 

On 10/5/2012 3:00 PM, bob smith wrote:
> So, I have a rectangle class as follows:
>
> public class My_Rectangle {
> double x, y, width, height;
> AffineTransform aft;
>
> Anyone know a good strategy for checking if a point is in the rectangle?
>
> The main difficulty is the transform.

I'll assume that x/y/width/height represent an untransformed
rectangle, and that you want to test whether the point is inside
the quadrilateral formed by transforming the rectangle with aft.
If that's the question, I see two approaches:

- Transform the rectangle and represent the result as a
Polygon, then use Polygon's contains() method.

- Inverse-transform the point and test whether the transformed
point is inside the original rectangle.

If that's not the question, please explain more fully.

--
Eric Sosman
esosman@comcast-dot-net.invalid

Re: rectangle contains point
 

On 10/05/2012 03:00 PM, bob smith wrote:
> So, I have a rectangle class as follows:
>
> public class My_Rectangle {
> double x, y, width, height;
> AffineTransform aft;
>
> Anyone know a good strategy for checking if a point is in the rectangle?
>
> The main difficulty is the transform.
John B. Matthews provided a strategy for this
in a reply to another of your recent posts.

Re: rectangle contains point
 

On Friday, October 5, 2012 2:23:18 PM UTC-5, Eric Sosman wrote:
> On 10/5/2012 3:00 PM, bob smith wrote:
>
> > So, I have a rectangle class as follows:
>
> >
>
> > public class My_Rectangle {
>
> > double x, y, width, height;
>
> > AffineTransform aft;
>
> >
>
> > Anyone know a good strategy for checking if a point is in the rectangle?
>
> >
>
> > The main difficulty is the transform.
>
>
>
> I'll assume that x/y/width/height represent an untransformed
>
> rectangle, and that you want to test whether the point is inside
>
> the quadrilateral formed by transforming the rectangle with aft.
>
> If that's the question, I see two approaches:
>
>
>
> - Transform the rectangle and represent the result as a
>
> Polygon, then use Polygon's contains() method.
>
>
>
> - Inverse-transform the point and test whether the transformed
>
> point is inside the original rectangle.
>
>
>
> If that's not the question, please explain more fully.
>
>
>
> --
>
> Eric Sosman
>
> esosman@comcast-dot-net.invalid

Excellent ideas. I went with inverse transform, and it works.

Thanks.