ZoomUtils.java

package org.archstudio.bna.utils;

import org.archstudio.bna.CoordinateMapperEvent;
import org.archstudio.bna.ICoordinateMapper;
import org.archstudio.bna.ICoordinateMapperListener;
import org.archstudio.bna.IMutableCoordinateMapper;
import org.archstudio.swtutils.SWTWidgetUtils;
import org.archstudio.sysutils.SystemUtils;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

public class ZoomUtils {

	public static final double[] ZOOM_VALUES = new double[] { 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90,
			1.00, 1.25, 1.50, 1.75, 2.00, 4.00, 8.00, 16.00 };

	public static double getNextLowestZoomValue(double currentZoomValue) {
		double lowestValue = ZOOM_VALUES[0];
		if (currentZoomValue <= lowestValue) {
			return currentZoomValue;
		}
		else {
			for (int i = 0; i < ZOOM_VALUES.length; i++) {
				if (currentZoomValue == ZOOM_VALUES[i]) {
					int index = i - 1;
					if (index < 0) {
						index = 0;
					}
					return ZOOM_VALUES[index];
				}
				if (currentZoomValue < ZOOM_VALUES[i]) {
					int index = i - 1;
					if (index < 0) {
						index = 0;
					}
					return ZOOM_VALUES[index];
				}
			}
		}
		return ZOOM_VALUES[ZOOM_VALUES.length - 1];
	}

	public static double getNextHighestZoomValue(double currentZoomValue) {
		double highestValue = ZOOM_VALUES[ZOOM_VALUES.length - 1];
		if (currentZoomValue >= highestValue) {
			return currentZoomValue;
		}
		else {
			for (int i = ZOOM_VALUES.length - 1; i >= 0; i--) {
				if (currentZoomValue == ZOOM_VALUES[i]) {
					int index = i + 1;
					if (index >= ZOOM_VALUES.length) {
						index = ZOOM_VALUES.length - 1;
					}
					return ZOOM_VALUES[index];
				}
				if (currentZoomValue > ZOOM_VALUES[i]) {
					int index = i + 1;
					if (index >= ZOOM_VALUES.length) {
						index = ZOOM_VALUES.length - 1;
					}
					return ZOOM_VALUES[index];
				}
			}
		}
		return ZOOM_VALUES[0];
	}

	public static String zoomLevelToString(double zoom) {
		return SystemUtils.round(zoom * 100.0d) + "%";
	}

	public static double stringToZoomLevel(String s) throws NumberFormatException {
		s = s.trim();
		if (s.endsWith("%")) {
			s = s.substring(0, s.length() - 1);
			s = s.trim();
		}
		int pct = Integer.parseInt(s);
		double scale = pct / 100.0d;
		return scale;
	}

	public static Control createZoomWidget(Composite parent, final Composite bna, final ICoordinateMapper cm) {
		boolean cmIsMutable = cm instanceof IMutableCoordinateMapper;

		final Combo combo = new Combo(parent, cmIsMutable ? SWT.NONE : SWT.READ_ONLY);
		String[] zoomLevels = new String[ZOOM_VALUES.length];
		int z = 0;
		for (int i = ZOOM_VALUES.length - 1; i >= 0; i--) {
			zoomLevels[z++] = zoomLevelToString(ZOOM_VALUES[i]);
		}
		combo.setItems(zoomLevels);
		combo.setText(zoomLevelToString(cm.getLocalScale()));

		final ICoordinateMapperListener cml = new ICoordinateMapperListener() {

			@Override
			public void coordinateMappingsChanged(final CoordinateMapperEvent evt) {
				SWTWidgetUtils.async(combo, new Runnable() {

					@Override
					public void run() {
						try {
							combo.setText(zoomLevelToString(evt.getNewLocalScale()));
						}
						catch (Throwable t) {
							t.printStackTrace();
						}
					}
				});
			}
		};
		cm.addCoordinateMapperListener(cml);

		if (cmIsMutable) {
			combo.addSelectionListener(new SelectionListener() {

				@Override
				public void widgetSelected(SelectionEvent e) {
					try {
						double newScale = stringToZoomLevel(combo.getText());
						if (newScale == cm.getLocalScale()) {
							return;
						}
						scaleToCenter(bna, (IMutableCoordinateMapper) cm, newScale);
					}
					catch (NumberFormatException nfe) {
						combo.setText(zoomLevelToString(cm.getLocalScale()));
					}
				}

				@Override
				public void widgetDefaultSelected(SelectionEvent e) {
					widgetSelected(e);
				}
			});
		}

		combo.addDisposeListener(new DisposeListener() {

			@Override
			public void widgetDisposed(DisposeEvent e) {
				cm.removeCoordinateMapperListener(cml);
			}
		});

		return combo;
	}

	public static void scaleToCenter(Control w, IMutableCoordinateMapper mcm, double newScale) {
		// TODO: I think this can be replaced with mcm.setLocalScaleAndAlign(localScale, localPoint, worldPoint)

		//		Point size = BNAUtils.toPoint(w.getSize());
		//		int lcx = size.x / 2;
		//		int lcy = size.y / 2;
		//		int worldCenterX = mcm.localXtoWorldX(lcx);
		//		int worldCenterY = mcm.localYtoWorldY(lcy);
		//
		//		mcm.rescaleAbsolute(newScale);
		//
		//		int newWorldCenterX = mcm.localXtoWorldX(lcx);
		//		int newWorldCenterY = mcm.localYtoWorldY(lcy);
		//		int dwcx = newWorldCenterX - worldCenterX;
		//		int dwcy = newWorldCenterY - worldCenterY;
		//		mcm.repositionRelative(-dwcx, -dwcy);
	}
}