import java.awt.*;
import ij.*;
import ij.gui.*;
import ij.plugin.filter.PlugInFilter;
import ij.process.*;

/**
 *	The user types in a width and height value, and the plugin creates
 *	a rectangular or oval  region of interest based on those values. 
 *	(Why? Because it can be time-consuming to repeatedly create a 
 *	ROI of an exact size with the mouse.)
 *
 *	@author	Jeffrey Kuhn
 *	@author	The University of Texas at Austin
 *	@author	jkuhn@ccwf.cc.utexas.edu
 */
public class SpecifyROI_ implements PlugInFilter {
	int iX;
	int	iY;		
	int iWidth, iHeight;
	boolean bAbort;
	ImagePlus imp;
	static boolean oval;

	/**
	 *	Called by ImageJ when the filter is loaded
	 */
	public int setup(String arg, ImagePlus imp) {
		this.imp = imp;
		if (arg.equals("about"))
			{showAbout(); return DONE;}
		return DOES_ALL+NO_CHANGES;
	}

	/**
	 *	Called by ImageJ to process the image
	 */
	public void run(ImageProcessor ip) {
		bAbort = false;
		Rectangle r = ip.getRoi();
		iWidth = r.width;
		iHeight = r.height;
		getROIWidthAndHeight();
		if (bAbort)
			return;
		iX = r.x;
		iY = r.y;
		iX += (r.width - iWidth) / 2;
		iY += (r.height - iHeight) / 2;
		if (oval)
			imp.setRoi(new OvalRoi(iX, iY, iWidth, iHeight,imp));
		else
			imp.setRoi(iX, iY, iWidth, iHeight);
		IJ.register(SpecifyROI_.class);
	}

	/**
	 *	Creates a dialog box, allowing the user to enter the requested
	 *	width and height of a rectangular Region Of Interest
	 */
	void getROIWidthAndHeight() {

		GenericDialog gd = new GenericDialog("ROI Size", IJ.getInstance());
		gd.addNumericField("Width:", iWidth, 0);
		gd.addNumericField("Height:", iHeight, 0);
		gd.addCheckbox("Oval", oval);

		gd.showDialog();

		if (gd.wasCanceled()) {

			bAbort = true;

			return;

		}
		iWidth = (int) gd.getNextNumber();
		iHeight = (int) gd.getNextNumber();
		oval = gd.getNextBoolean();

	}

	/**
	 *	Displays a short message describing the filter
	 */
	void showAbout() {
		IJ.showMessage("About ROISelect_...",
			"This sample allows a ROI of a specific size to be specified.\n"
		);
	}

}