Contains method doesn't seem to work with a point inside my polygon
I am trying to add a functionnality which would let me see if a point is inside a polygon.
Here's the code snippet to see if the point is inside my polygon
int x = 265;
int y = 300;
List<Point> points = new ArrayList<Point>();
points.add(new Point(233,155));
points.add(new Point(347,269));
points.add(new Point(136,251));
points.add(new Point(250,366));
Polygon polygon = new Polygon();//java.awt.Polygon
for(Point point : points) {
polygon.addPoint(point.x, point.y);
}
return polygon.contains(x,y);
The code seems to work if my point is closer to the upper-left side of the polygon, however when the point is on the bottom-right side, the method contains will return false.
Graph of my polygon and the point in question : https://www.desmos.com/calculator/tnglrdpivn
Any idea why this happens ?
java 2d awt polygon
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
add a comment |
I am trying to add a functionnality which would let me see if a point is inside a polygon.
Here's the code snippet to see if the point is inside my polygon
int x = 265;
int y = 300;
List<Point> points = new ArrayList<Point>();
points.add(new Point(233,155));
points.add(new Point(347,269));
points.add(new Point(136,251));
points.add(new Point(250,366));
Polygon polygon = new Polygon();//java.awt.Polygon
for(Point point : points) {
polygon.addPoint(point.x, point.y);
}
return polygon.contains(x,y);
The code seems to work if my point is closer to the upper-left side of the polygon, however when the point is on the bottom-right side, the method contains will return false.
Graph of my polygon and the point in question : https://www.desmos.com/calculator/tnglrdpivn
Any idea why this happens ?
java 2d awt polygon
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
In order for us to help, what are thepointsand what arex&ythat reproduce the issue you're having? Also make sure you read thru the definition of insideness for this implementation.
– Krease
Nov 15 '18 at 23:25
For better help sooner, post a Minimal, Complete, and Verifiable example or Short, Self Contained, Correct Example.
– Andrew Thompson
Nov 15 '18 at 23:27
1
@Krease as you have requested I've added more info to make my question clearer, thanks for your input.
– J. Lev
Nov 15 '18 at 23:40
Much clearer now - see my answer.
– Krease
Nov 16 '18 at 0:05
add a comment |
I am trying to add a functionnality which would let me see if a point is inside a polygon.
Here's the code snippet to see if the point is inside my polygon
int x = 265;
int y = 300;
List<Point> points = new ArrayList<Point>();
points.add(new Point(233,155));
points.add(new Point(347,269));
points.add(new Point(136,251));
points.add(new Point(250,366));
Polygon polygon = new Polygon();//java.awt.Polygon
for(Point point : points) {
polygon.addPoint(point.x, point.y);
}
return polygon.contains(x,y);
The code seems to work if my point is closer to the upper-left side of the polygon, however when the point is on the bottom-right side, the method contains will return false.
Graph of my polygon and the point in question : https://www.desmos.com/calculator/tnglrdpivn
Any idea why this happens ?
java 2d awt polygon
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
I am trying to add a functionnality which would let me see if a point is inside a polygon.
Here's the code snippet to see if the point is inside my polygon
int x = 265;
int y = 300;
List<Point> points = new ArrayList<Point>();
points.add(new Point(233,155));
points.add(new Point(347,269));
points.add(new Point(136,251));
points.add(new Point(250,366));
Polygon polygon = new Polygon();//java.awt.Polygon
for(Point point : points) {
polygon.addPoint(point.x, point.y);
}
return polygon.contains(x,y);
The code seems to work if my point is closer to the upper-left side of the polygon, however when the point is on the bottom-right side, the method contains will return false.
Graph of my polygon and the point in question : https://www.desmos.com/calculator/tnglrdpivn
Any idea why this happens ?
java 2d awt polygon
java 2d awt polygon
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
edited Nov 16 '18 at 0:02
J. Lev
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
asked Nov 15 '18 at 23:17
J. LevJ. Lev
89112
89112
In order for us to help, what are thepointsand what arex&ythat reproduce the issue you're having? Also make sure you read thru the definition of insideness for this implementation.
– Krease
Nov 15 '18 at 23:25
For better help sooner, post a Minimal, Complete, and Verifiable example or Short, Self Contained, Correct Example.
– Andrew Thompson
Nov 15 '18 at 23:27
1
@Krease as you have requested I've added more info to make my question clearer, thanks for your input.
– J. Lev
Nov 15 '18 at 23:40
Much clearer now - see my answer.
– Krease
Nov 16 '18 at 0:05
add a comment |
In order for us to help, what are thepointsand what arex&ythat reproduce the issue you're having? Also make sure you read thru the definition of insideness for this implementation.
– Krease
Nov 15 '18 at 23:25
For better help sooner, post a Minimal, Complete, and Verifiable example or Short, Self Contained, Correct Example.
– Andrew Thompson
Nov 15 '18 at 23:27
1
@Krease as you have requested I've added more info to make my question clearer, thanks for your input.
– J. Lev
Nov 15 '18 at 23:40
Much clearer now - see my answer.
– Krease
Nov 16 '18 at 0:05
In order for us to help, what are the
points and what are x & y that reproduce the issue you're having? Also make sure you read thru the definition of insideness for this implementation.– Krease
Nov 15 '18 at 23:25
In order for us to help, what are the
points and what are x & y that reproduce the issue you're having? Also make sure you read thru the definition of insideness for this implementation.– Krease
Nov 15 '18 at 23:25
For better help sooner, post a Minimal, Complete, and Verifiable example or Short, Self Contained, Correct Example.
– Andrew Thompson
Nov 15 '18 at 23:27
For better help sooner, post a Minimal, Complete, and Verifiable example or Short, Self Contained, Correct Example.
– Andrew Thompson
Nov 15 '18 at 23:27
1
1
@Krease as you have requested I've added more info to make my question clearer, thanks for your input.
– J. Lev
Nov 15 '18 at 23:40
@Krease as you have requested I've added more info to make my question clearer, thanks for your input.
– J. Lev
Nov 15 '18 at 23:40
Much clearer now - see my answer.
– Krease
Nov 16 '18 at 0:05
Much clearer now - see my answer.
– Krease
Nov 16 '18 at 0:05
add a comment |
1 Answer
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active
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The key here is in the ordering of your points. Though plotted all at once on a graph, they look like they form a nice looking polygon, if you play connect-the-dots with them in the order you add them to the polygon, they form a very weird shape, and the point is really not contained in the polygon.
If you reverse the order of your last two points, the connect-the-dots polygon is properly formed, and then the point is contained in the polygon.
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
add a comment |
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The key here is in the ordering of your points. Though plotted all at once on a graph, they look like they form a nice looking polygon, if you play connect-the-dots with them in the order you add them to the polygon, they form a very weird shape, and the point is really not contained in the polygon.
If you reverse the order of your last two points, the connect-the-dots polygon is properly formed, and then the point is contained in the polygon.
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
add a comment |
The key here is in the ordering of your points. Though plotted all at once on a graph, they look like they form a nice looking polygon, if you play connect-the-dots with them in the order you add them to the polygon, they form a very weird shape, and the point is really not contained in the polygon.
If you reverse the order of your last two points, the connect-the-dots polygon is properly formed, and then the point is contained in the polygon.
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
add a comment |
The key here is in the ordering of your points. Though plotted all at once on a graph, they look like they form a nice looking polygon, if you play connect-the-dots with them in the order you add them to the polygon, they form a very weird shape, and the point is really not contained in the polygon.
If you reverse the order of your last two points, the connect-the-dots polygon is properly formed, and then the point is contained in the polygon.
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
The key here is in the ordering of your points. Though plotted all at once on a graph, they look like they form a nice looking polygon, if you play connect-the-dots with them in the order you add them to the polygon, they form a very weird shape, and the point is really not contained in the polygon.
If you reverse the order of your last two points, the connect-the-dots polygon is properly formed, and then the point is contained in the polygon.
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
answered Nov 16 '18 at 0:04
KreaseKrease
11.7k74162
11.7k74162
add a comment |
add a comment |
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In order for us to help, what are the
pointsand what arex&ythat reproduce the issue you're having? Also make sure you read thru the definition of insideness for this implementation.– Krease
Nov 15 '18 at 23:25
For better help sooner, post a Minimal, Complete, and Verifiable example or Short, Self Contained, Correct Example.
– Andrew Thompson
Nov 15 '18 at 23:27
1
@Krease as you have requested I've added more info to make my question clearer, thanks for your input.
– J. Lev
Nov 15 '18 at 23:40
Much clearer now - see my answer.
– Krease
Nov 16 '18 at 0:05