Keystone corner co-ordinates from XML

stphnmnslw

Keystone corner co-ordinates from XML

in Contributed Library Questions • 1 year ago

Hello,

I am using the keystone library and I want to get the co-ordinates for each of the surfaces I'm using from the XML file. I have tried code like:

quadcoords = new XMLElement(this, "keystone.xml");

int numXMLelements = quadcoords.getChildCount();

for ( int i = 0; i < numXMLelements; i++) {

XMLElement point = quadcoords.getChild(i);

PVector[] posit = new PVector[point.getInt("i")];

posit[i] = new PVector();

posit.x = point.getFloat("x");

posit.y = point.getFloat("y");

}

This doesn't work because i think its illegal to make a PVector Array in this way but i'm stuck on how to do this.

here is a sample XML file:

</surface>

</surface>

</surface>

</surface>

</keystone>

If anyone knows how to properly extract this data I would really appreciate your help and can offer a reward!.

all the best,

Stephen

Replies(4)

maleo

Re: Keystone corner co-ordinates from XML

1 year ago

so you're only interested in the x, y attributes of the point elements?

notice the children of the root element are the surface elements, so you need to get their children again in order to get to the points.

XMLElement quadcoords = new XMLElement(this, "keystone.xml");
int numXMLelements = quadcoords.getChildCount();
// arraylist to hold all the point elements from xml
ArrayList<PVector> points = new ArrayList<PVector>();
// surface elements
for ( int i = 0; i < numXMLelements; i++) {
XMLElement surface = quadcoords.getChild(i);
int numPoints = surface.getChildCount();
// point elements
for (int j=0; j<numPoints; j++) {
XMLElement point = surface.getChild(j);
float x = point.getFloat("x");
float y = point.getFloat("y");
points.add(new PVector(x, y));
}
}
for (int i=0; i<points.size(); i++) {
PVector p = points.get(i);
println(p);
}

stphnmnslw

Re: Keystone corner co-ordinates from XML

1 year ago

thanks for this mate i'm going to give this a try today, really appreciate your help.

stphnmnslw

Re: Keystone corner co-ordinates from XML

1 year ago

Just after I posted this question I changed the library i'm using to surface mapper by ixagon but it looks like it has a virtually identical XML layout so I won't have to change your code that much at all I think or I can figure out the int[].getcornerpoints() method.

Surface Mapper handles what I'm doing with the surfaces in a really nice way allowing for dynamic creation of surfaces whereas the other libraries you need to hard code them in to begin with. I am also finding it has a massive performance boost when handling lots of video's but I don't think I was being very efficient with how I programmed it.

If anyone else is interested the reason I want to get the co-ordinates is so I can make polygons over each surface to flash white and mask with instead of doing this within the surface;s offscreen beginDraw() and endDraw() . this means I can flash the individual surfaces independently of the content and do other masking tricks.

stphnmnslw

Re: Keystone corner co-ordinates from XML

1 year ago

I didn't have to change your code at all to get it to work with the surface mapper library cheers mate! I did promise you a reward send me an email to stphnmnslw@gmail.com

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