/**
* This is used to convert an image'x x,y location into lonLat values.
*
* @param x x pixel of user click on image
* @param y y pixel of user click on image
* @param intWESN is the WESN of the graph on the image. Note that S will be numerically greater
* than N.
* @param doubleWESN is the lon lat WESN of the graph on the image
* @param extentWESN is the maximum extent allowed (so center not shifted too far)
* @return double[2] 0=lon 1=lat. or null if trouble (e.g., intWESN is null)
*/
public static double[] xyToLonLat(
int x, int y, int[] intWESN, double[] doubleWESN, double[] extentWESN) {
if (intWESN == null
|| doubleWESN == null
|| intWESN[0] >= intWESN[1]
|| intWESN[2] <= intWESN[3]) return null;
double xRange = doubleWESN[1] - doubleWESN[0];
double yRange = doubleWESN[3] - doubleWESN[2];
double newX, newY;
if (x < intWESN[0] || x > intWESN[1]) {
// a click outside of graph shifts center to (theoretical) adjacent panel
newX = x < intWESN[0] ? doubleWESN[0] - xRange / 2 : doubleWESN[1] + xRange / 2;
newY =
y < intWESN[3]
? doubleWESN[3] + yRange / 2
: // N
y > intWESN[2]
? doubleWESN[2] - yRange / 2
: // S
doubleWESN[2] + yRange / 2;
// ensure not too far
newX = Math.max(newX, extentWESN[0] + xRange / 2);
newX = Math.min(newX, extentWESN[1] - xRange / 2);
newY = Math.max(newY, extentWESN[2] + yRange / 2);
newY = Math.min(newY, extentWESN[3] - yRange / 2);
} else if (y < intWESN[3] || y > intWESN[2]) {
// y is outside of graph, but x must be within graph
newX = doubleWESN[0] + xRange / 2;
newY = y < intWESN[3] ? doubleWESN[3] + yRange / 2 : doubleWESN[2] - yRange / 2;
// ensure not too far
newX = Math.max(newX, extentWESN[0] + xRange / 2);
newX = Math.min(newX, extentWESN[1] - xRange / 2);
newY = Math.max(newY, extentWESN[2] + yRange / 2);
newY = Math.min(newY, extentWESN[3] - yRange / 2);
} else {
// click within the graph
newX = doubleWESN[0] + (x - intWESN[0]) * xRange / (intWESN[1] - intWESN[0]);
newY = doubleWESN[2] + (y - intWESN[2]) * yRange / (intWESN[3] - intWESN[2]);
}
return new double[] {newX, newY};
}
