--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-client/src/main/java/org/dive4elements/river/client/client/ui/chart/ZoomboxControl.java	Thu Apr 25 12:31:32 2013 +0200
@@ -0,0 +1,324 @@
+package de.intevation.flys.client.client.ui.chart;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.google.gwt.core.client.GWT;
+
+import com.smartgwt.client.types.Positioning;
+import com.smartgwt.client.types.SelectionType;
+import com.smartgwt.client.widgets.ImgButton;
+import com.smartgwt.client.widgets.Canvas;
+import com.smartgwt.client.widgets.events.MouseDownEvent;
+import com.smartgwt.client.widgets.events.MouseDownHandler;
+import com.smartgwt.client.widgets.events.MouseMoveEvent;
+import com.smartgwt.client.widgets.events.MouseMoveHandler;
+import com.smartgwt.client.widgets.events.MouseOutEvent;
+import com.smartgwt.client.widgets.events.MouseOutHandler;
+import com.smartgwt.client.widgets.events.MouseUpEvent;
+import com.smartgwt.client.widgets.events.MouseUpHandler;
+
+import de.intevation.flys.client.client.event.HasZoomHandlers;
+import de.intevation.flys.client.client.event.ZoomEvent;
+import de.intevation.flys.client.client.event.ZoomHandler;
+
+
+/**
+ * This control observes that panel retrieved by ChartOutputTab.getChartPanel().
+ * If activated, a zoombox is drawn. One of the two edges is the position of the
+ * mouse down event on the observed panel. The other edge is specified by the
+ * current mouse position. If the mouse up event occurs, start and end point
+ * relative to the left and upper border of the observed panel is determined and
+ * a ZoomEvent is fired.
+ *
+ * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
+ */
+public class ZoomboxControl
+extends      ImgButton
+implements   MouseDownHandler, MouseUpHandler, MouseMoveHandler, HasZoomHandlers,
+             MouseOutHandler
+{
+    protected List<ZoomHandler> handlers;
+
+    protected ChartOutputTab chartTab;
+
+    protected Canvas zoombox;
+
+    protected int[] start;
+    protected int[] end;
+
+
+    public ZoomboxControl(ChartOutputTab chartTab, String imageUrl) {
+        super();
+
+        this.handlers = new ArrayList<ZoomHandler>();
+        this.chartTab = chartTab;
+        this.start    = new int[] { -1, -1 };
+        this.end      = new int[2];
+        this.zoombox  = new Canvas();
+
+        initZoombox();
+
+        String baseUrl = GWT.getHostPageBaseURL();
+        setSrc(baseUrl + imageUrl);
+        setActionType(SelectionType.CHECKBOX);
+        setSize(20);
+        setShowRollOver(false);
+        setSelected(false);
+
+        Canvas chart = chartTab.getChartPanel();
+        chart.addMouseDownHandler(this);
+        chart.addMouseOutHandler(this);
+        chart.addMouseMoveHandler(this);
+        chart.addMouseUpHandler(this);
+    }
+
+
+    /**
+     * Initializes the zoombox that is displayed over the observed area. The
+     * zoombox has an opaque background. Its height/width and x/y values are
+     * determined by the start point (mouse down) and the current mouse
+     * position.
+     */
+    protected void initZoombox() {
+        Canvas chart = chartTab.getChartPanel();
+        chart.addChild(zoombox);
+
+        zoombox.setPosition(Positioning.ABSOLUTE);
+        zoombox.setBorder("2px solid black");
+        zoombox.setOpacity(50);
+        zoombox.setWidth(1);
+        zoombox.setHeight(1);
+        zoombox.setLeft(-10000);
+        zoombox.setTop(-10000);
+    }
+
+
+    /**
+     * Registers a new ZoomHandler that wants to listen to ZoomEvents.
+     *
+     * @param handler A new ZoomHandler.
+     */
+    public void addZoomHandler(ZoomHandler handler) {
+        if (handler != null) {
+            handlers.add(handler);
+        }
+    }
+
+
+    /**
+     * A mouse down event on the specified area will set the start point for the
+     * zoombox.
+     *
+     * @param event The mouse down event which contains the xy coordinates of
+     * the observed area.
+     */
+    public void onMouseDown(MouseDownEvent event) {
+        if (!isSelected()) {
+            return;
+        }
+
+        start[0] = getRelativeX(event.getX()) - 1;
+        start[1] = getRelativeY(event.getY()) + 1;
+
+        end[0] = start[0];
+        end[1] = start[1];
+    }
+
+
+    /**
+     * A mouse move event on the specified area will set the end point for the
+     * zoombox. If the end point differs from the start point, an opaque box is
+     * displayed.
+     *
+     * @param event The mouse move event which contains the xy coordinates of
+     * the observed area.
+     */
+    public void onMouseMove(MouseMoveEvent event) {
+        if (!isSelected() || !isZooming()) {
+            return;
+        }
+
+        int x = getRelativeX(event.getX());
+        int y = getRelativeY(event.getY());
+
+        end[0] = x > start[0] ? x-1 : x+1;
+        end[1] = y > start[1] ? y-1 : y+1;
+
+        positionZoombox();
+    }
+
+
+    /**
+     * The mouse up event finalizes the zoom operation. It sets the end point
+     * for this operation, clears the zoombox and fires a ZoomEvent.
+     *
+     * @param event The mouse up event which contains the xy coordinates of the
+     * observed area.
+     */
+    public void onMouseUp(MouseUpEvent event) {
+        if (!isSelected()) {
+            return;
+        }
+
+        end[0] = getRelativeX(event.getX());
+        end[1] = getRelativeY(event.getY());
+
+        fireZoomEvent();
+
+        reset();
+    }
+
+
+    /**
+     * The mouse out event is used to cancel an active zoom operation.
+     *
+     * @param event The mouse out event.
+     */
+    public void onMouseOut(MouseOutEvent event) {
+        if (!isSelected() || !isMouseOut(event.getX(), event.getY())) {
+            return;
+        }
+
+        reset();
+    }
+
+
+    /**
+     * Returns the chart panel.
+     *
+     * @return the chart panel.
+     */
+    protected Canvas getChartPanel() {
+        return chartTab.getChartPanel();
+    }
+
+
+    /**
+     * This method is required to check manually if the mouse pointer really
+     * moves out the chart area. The MouseOutEvent is also fired if the mouse
+     * goes down which doesn't seem to be correct. So, we gonna check this
+     * manually.
+     *
+     * @param x The x coordinate.
+     * @param y The y coordinate.
+     *
+     * @return true, if the mouse is really out of the chart area, otherwise
+     * false.
+     */
+    protected boolean isMouseOut(int x, int y) {
+        Canvas chart = getChartPanel();
+
+        int left   = chart.getPageLeft();
+        int right  = chart.getPageRight();
+        int top    = chart.getPageTop();
+        int bottom = chart.getPageBottom();
+
+        if (x <= left || x >= right || y <= top || y >= bottom) {
+            return true;
+        }
+
+        return false;
+    }
+
+
+    /**
+     * Returns true, if a zoom action is in process.
+     *
+     * @return true, if a zoom action is in process.
+     */
+    public boolean isZooming() {
+        return start[0] > 0 && start[1] > 0;
+    }
+
+
+    /**
+     * Returns the X coordinate relative to the left border.
+     *
+     * @param x The X coordinate relative to the window.
+     *
+     * @return the X coordinate relative to the left border.
+     */
+    protected int getRelativeX(int x) {
+        return x - chartTab.getChartPanel().getPageLeft();
+    }
+
+
+    /**
+     * Returns the Y coordinate relative to the top border.
+     *
+     * @param y The Y coordinate relative to the window.
+     *
+     * @return the Y coordinate relative to the top border.
+     */
+    protected int getRelativeY(int y) {
+        return y - chartTab.getChartPanel().getPageTop();
+    }
+
+
+    /**
+     * Returns min and max x/y values based on the stored values in <i>start</i>
+     * and <i>end</i>.
+     *
+     * @return an int[] as follows: [xmin, ymin, xmax, ymax].
+     */
+    protected int[] orderPositions() {
+        int xmin = start[0] < end[0] ? start[0] : end[0];
+        int ymin = start[1] < end[1] ? start[1] : end[1];
+
+        int xmax = start[0] >= end[0] ? start[0] : end[0];
+        int ymax = start[1] >= end[1] ? start[1] : end[1];
+
+        return new int[] { xmin, ymin, xmax, ymax };
+    }
+
+
+    /**
+     * Sets the width, height, x and y values of the zoombox.
+     */
+    protected void positionZoombox() {
+        int[] values = orderPositions();
+
+        zoombox.setLeft(values[0]);
+        zoombox.setTop(values[1]);
+        zoombox.setWidth(values[2] - values[0]);
+        zoombox.setHeight(values[3] - values[1]);
+    }
+
+
+    /**
+     * Clears the zoombox (set position and size to null).
+     */
+    protected void clearZoombox() {
+        zoombox.setLeft(-10000);
+        zoombox.setTop(-10000);
+        zoombox.setWidth(1);
+        zoombox.setHeight(1);
+    }
+
+
+    /**
+     * Resets the zoom control (start point and zoombox).
+     */
+    protected void reset() {
+        start[0] = -1;
+        start[1] = -1;
+
+        clearZoombox();
+    }
+
+
+    /**
+     * Fires a ZoomEvent to all registered listeners.
+     */
+    protected void fireZoomEvent() {
+        int[] pos = orderPositions();
+
+        ZoomEvent event = new ZoomEvent(pos[0], pos[1], pos[2], pos[3]);
+
+        for (ZoomHandler handler: handlers) {
+            handler.onZoom(event);
+        }
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :