import ij.*;
import ij.process.*;
import ij.measure.*;
import ij.gui.*;
import java.awt.*;
import ij.plugin.*;
import SK.gnome.twain.*;

public class Twain_ implements PlugIn {

	public void run(String arg) {
		ImagePlus imp  = scan();
		if (imp!=null)
			imp.show();
	}

	public ImagePlus scan() {
		Image image = null;
		try {image = Toolkit.getDefaultToolkit().createImage(new Twain());}
		catch (Throwable e) {needsGnome(e);}
		TwainException twainException=Twain.getLastException();
		if(twainException!=null)
			IJ.showMessage("TWAIN Error", ""+twainException);
		if (image==null)
			return null;
		ImagePlus imp = new ImagePlus("Untitled", image);
		getUnits(imp);
		return imp;
	}

	void needsGnome(Throwable e) {
		if (!IJ.isMacintosh())
			IJ.error("The Twain plug-in requires the Java Twain Package from\n"
				+ "http://www.gnome.sk/. The files 'twain.jar' and 'JavaTwain32.dll'\n"
				+ "from this package must be placed in the ImageJ folder and twain.jar \n"
				+ "must be added to the -cp option of the command that runs ImageJ.\n \n"
				+ e);
		
	}

	void getUnits(ImagePlus imp) {
		String unit;
		int code = TwainEx.getCurrentUnits();
		if (code==0)
			unit = "inch";
		else if (code==1)
			unit = "cm";
		else
			unit = "";
		double xResolution = TwainEx.getXResolution();
		double yResolution = TwainEx.getYResolution();
		if (xResolution!=0.0 && yResolution!=0.0) {
			Calibration cal = imp.getCalibration();
			cal.pixelWidth = 1/xResolution;
			cal.pixelHeight = 1/yResolution;
			cal.setUnit(unit);			
		}
	}
}