The contains() method is only implemented for paths.

Programming Questions

bkickhoef..

The contains() method is only implemented for paths.

in Programming Questions • 10 months ago

Hi all,

I figured out a way of how to read in an ESRI shape file, and how to convert the features into a PShape:

private PShape getPShape(Feature ft) {
        PShape featureShape;
        GeometryCollection gc = (GeometryCollection) ft.getDefaultGeometry();
        PVector[] scrCoords = getScreenCoords(gc);

        if(gc instanceof MultiLineString){
            featureShape = createShape(LINES);
            for(PVector scrCoord : scrCoords){
                featureShape.vertex(scrCoord.x, scrCoord.y);
            }
            featureShape.noFill();
            featureShape.stroke(150, 50, 50);
            featureShape.strokeWeight(1);
            featureShape.end();
        } else if(gc instanceof MultiPolygon){
            featureShape = createShape();
            for(PVector scrCoord : scrCoords){
                featureShape.vertex(scrCoord.x, scrCoord.y);
            }
            featureShape.noFill();
            featureShape.stroke(255, 255, 255);
            featureShape.strokeWeight(5);
            featureShape.end(CLOSE);
        } else {
            throw new RuntimeException("Unsupported GeometryType: " + gc.getGeometryType());
        }

private PVector[] getScreenCoords(GeometryCollection gc) {
        Coordinate[] coords = gc.getCoordinates();
        PVector[] scrCoords = new PVector[coords.length];

        for(int i=0; i<coords.length; i++){
            PVector coord = new PVector((float) coords[i].x, (float) coords[i].y);
            PVector scrCoord = geoToScreen(coord);
            scrCoords[i] = scrCoord;
        }
        return scrCoords;
    }

Now I would like to fill the PShape whenever the mouse is over it. The obvious way (see below) gives me the error message of the topic header.

@Override
    public void draw(){
        shape(munich);

        for(PShape childShape : munich.getChildren()){
            if(childShape.contains(mouseX, mouseY)){
                childShape.fill(255, 255, 255);
            }
        }
    }

I found some external libraries (e.g. http://www.ricardmarxer.com/geomerative/ or http://code.google.com/p/gicentre-geomap/) that might help here, but their classes limit my work in other ways. So I would be interested if someone has an idea about how to solve my problem with "standard processing".

Any comments are very welcome!

Thanks in advance,
Benjamin

Replies(2)

PhiLho

Re: The contains() method is only implemented for paths.

10 months ago

I am not sure as I only glanced at the code, but perhaps try to replace:
featureShape = createShape(LINES);
by
featureShape = createShape(PATH);
since that's what contains() expects: it wants a closed path, not a bunch of possibly disconnected lines.

bkickhoef..

Re: The contains() method is only implemented for paths.

10 months ago

Hi PhiLho,

thanks for your answer. However, this does not work; the reason is that

featureShape = createShape();
...
featureShape.end(CLOSE);

should already produce a closed shape. You were looking at

featureShape = createShape(LINES);
...
featureShape.end

which I use for MultiLineStrings that come from the ESRI shape file. Obviously, I dont want to use

PShape.contains()

there. A simple (but probably ugly) workaround that I tried is to construct a java.awt.Polygon for every shape

private Polygon getPolygon(PShape shape) {
        int vertexCount = shape.getVertexCount();

        int[] xCoords = new int[vertexCount];
        int[] yCoords = new int[vertexCount];

        for(int i=0; i<vertexCount; i++){
            xCoords[i] = (int) shape.getVertex(i).x;
            yCoords[i] = (int) shape.getVertex(i).y;
        }
        return new Polygon(xCoords, yCoords, vertexCount);
    }

This is described in a similar way here. Maybe it is better not even convert the Features to the (so far) not completely sofisticated PShape, but rather write my own drawMe() function for awt.Polygon as proposed in the link above...

Anyone else any ideas?

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