--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-client/src/main/java/org/dive4elements/river/client/client/ui/chart/PanControl.java	Thu Apr 25 12:31:32 2013 +0200
@@ -0,0 +1,210 @@
+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.SelectionType;
+import com.smartgwt.client.widgets.Canvas;
+import com.smartgwt.client.widgets.Img;
+import com.smartgwt.client.widgets.ImgButton;
+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.HasPanHandlers;
+import de.intevation.flys.client.client.event.PanEvent;
+import de.intevation.flys.client.client.event.PanHandler;
+
+
+/**
+ * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
+ */
+public class PanControl
+extends      ImgButton
+implements   MouseDownHandler, MouseMoveHandler, MouseUpHandler,
+             MouseOutHandler, HasPanHandlers
+{
+    protected ChartOutputTab chartTab;
+
+    protected List<PanHandler> handlers;
+
+    protected int[] start;
+    protected int[] end;
+
+
+    public PanControl(ChartOutputTab chartTab, String imageUrl) {
+        super();
+
+        this.chartTab = chartTab;
+        this.handlers = new ArrayList<PanHandler>();
+        this.start    = new int[] { -1, -1 };
+        this.end      = new int[] { -1, -1 };
+
+        String baseUrl = GWT.getHostPageBaseURL();
+        setSrc(baseUrl + imageUrl);
+        setActionType(SelectionType.CHECKBOX);
+        setSize(20);
+        setShowRollOver(false);
+        setSelected(false);
+
+        chartTab.getChartPanel().addMouseDownHandler(this);
+        chartTab.getChartPanel().addMouseMoveHandler(this);
+        chartTab.getChartPanel().addMouseUpHandler(this);
+        chartTab.getChartPanel().addMouseOutHandler(this);
+    }
+
+
+    /**
+     * Method used to register a new PanHandler.
+     *
+     * @param handler A new PanHandler.
+     */
+    public void addPanHandler(PanHandler handler) {
+        if (handler != null) {
+            handlers.add(handler);
+        }
+    }
+
+
+    /**
+     * This event starts the dragging operation if the control is activated.
+     *
+     * @param event The mouse down event which contains the start coordinates.
+     */
+    public void onMouseDown(MouseDownEvent event) {
+        if (!isSelected()) {
+            return;
+        }
+
+        start[0] = event.getX();
+        start[1] = event.getY();
+
+        end[0] = start[0];
+        end[1] = start[1];
+    }
+
+
+    /**
+     * This event is used to reposition the chart image based on the current
+     * drag operation.
+     *
+     * @param event The move event which contains the new coordinates to update
+     * the chart image position.
+     */
+    public void onMouseMove(MouseMoveEvent event) {
+        if (!isSelected() || start[0] == -1 || start[1] == -1) {
+            return;
+        }
+
+        int x = event.getX() - end[0];
+        int y = event.getY() - end[1];
+
+        end[0] = end[0] + x;
+        end[1] = end[1] + y;
+
+        Canvas c = chartTab.getChartImg();
+        c.moveBy(x, y);
+    }
+
+
+    /**
+     * This event stops the dragging operation and fires a DragEnd event to the
+     * registered listeners.
+     *
+     * @param event The mouse up event which contains the end coordinates.
+     */
+    public void onMouseUp(MouseUpEvent event) {
+        if (!isSelected()) {
+            return;
+        }
+
+        end[0] = event.getX();
+        end[1] = event.getY();
+
+        Canvas c = chartTab.getChartImg();
+        c.setLeft(0);
+        c.setTop(0);
+
+        fireOnPan();
+
+        start[0] = -1;
+        start[1] = -1;
+    }
+
+
+    /**
+     * This event is used to cancel the current dragging operation.
+     *
+     * @param event The mouse out event.
+     */
+    public void onMouseOut(MouseOutEvent event) {
+        int x = event.getX();
+        int y = event.getY();
+
+        if (!isSelected() || !isMouseOut(x, y) || start[0] == -1) {
+            return;
+        }
+
+        Canvas c = chartTab.getChartImg();
+        c.setLeft(0);
+        c.setTop(0);
+
+        fireOnPan();
+
+        start[0] = -1;
+        start[1] = -1;
+    }
+
+
+    /**
+     * 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 = chartTab.getChartImg();
+
+        if (chart instanceof Img) {
+            chart = chart.getParentElement();
+        }
+
+        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;
+    }
+
+
+    /**
+     * A pan event is fired to inform the registered listeners about a pan
+     * operation has finished.
+     */
+    protected void fireOnPan() {
+        PanEvent event = new PanEvent(start, end);
+
+        for (PanHandler handler: handlers) {
+            handler.onPan(event);
+        }
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :