--- a/flys-client/src/main/java/de/intevation/flys/client/client/ui/chart/ChartOutputTab.java	Thu Jun 09 06:05:44 2011 +0000
+++ b/flys-client/src/main/java/de/intevation/flys/client/client/ui/chart/ChartOutputTab.java	Thu Jun 09 10:57:42 2011 +0000
@@ -57,7 +57,7 @@
     protected ChartInfo chartInfo;
 
     /** The transformer used to transform image pixels into chart coordinates.*/
-    protected Transform2D transformer;
+    protected Transform2D[] transformer;
 
     /** The collection view.*/
     protected CollectionView view;
@@ -74,8 +74,10 @@
 
 
     /** Chart zoom options.*/
-    protected double[] xrange;
-    protected double[] yrange;
+    protected int[] xrange;
+    protected int[] yrange;
+
+    protected double[] zoom;
 
 
     /**
@@ -97,8 +99,9 @@
         left      = new Canvas();
         right     = new Canvas();
         tbarPanel = new ChartToolbar(collectionView, this);
-        xrange    = new double[2];
-        yrange    = new double[2];
+        xrange    = new int[2];
+        yrange    = new int[2];
+        zoom      = new double[4];
 
         left.setBorder("1px solid black");
         left.setWidth(THEMEPANEL_MIN_WIDTH);
@@ -139,7 +142,7 @@
      */
     public void onResized(ResizedEvent event) {
         updateChartPanel();
-        updateTransformer();
+        updateChartInfo();
     }
 
 
@@ -160,63 +163,126 @@
      * @param evt The ZoomEvent that stores the coordinates for zooming.
      */
     public void onZoom(ZoomEvent evt) {
-        if (transformer == null) {
-            return;
-        }
-        double[] lower = transformer.transform(evt.getStartX(), evt.getStartY());
-        double[] upper = transformer.transform(evt.getEndX(), evt.getEndY());
+        xrange[0] = evt.getStartX();
+        xrange[1] = evt.getEndX();
+        yrange[0] = evt.getStartY();
+        yrange[1] = evt.getEndY();
 
-        xrange[0] = lower[0];
-        xrange[1] = upper[0];
-        yrange[0] = upper[1];
-        yrange[1] = lower[1];
+        xrange[0] = xrange[0] < xrange[1] ? xrange[0] : xrange[1];
+        yrange[0] = yrange[0] < yrange[1] ? yrange[0] : yrange[1];
 
-        updateTransformer();
+        translateCoordinates();
+
+        updateChartInfo();
         updateChartPanel();
     }
 
 
+    protected double[] translateCoordinates() {
+        if (xrange == null || (xrange[0] == 0 && xrange[1] == 0)) {
+            zoom[0] = 0d;
+            zoom[1] = 1d;
+        }
+        else {
+            translateXCoordinates();
+        }
+
+        if (yrange == null || (yrange[0] == 0 && yrange[1] == 0)) {
+            zoom[2] = 0d;
+            zoom[3] = 1d;
+        }
+        else {
+            translateYCoordinates();
+        }
+
+        return zoom;
+    }
+
+
+    protected void translateXCoordinates() {
+        Axis xAxis = chartInfo.getXAxis(0);
+
+        double xmin   = xAxis.getMin();
+        double xmax   = xAxis.getMax();
+        double xRange = xmax - xmin;
+
+        Transform2D transformer = getTransformer(0);
+
+        double[] start = transformer.transform(xrange[0], yrange[0]);
+        double[] end   = transformer.transform(xrange[1], yrange[1]);
+
+        zoom[0] = (start[0] - xmin) / xRange;
+        zoom[1] = (end[0] - xmin) / xRange;
+    }
+
+
+    protected void translateYCoordinates() {
+        Axis yAxis = chartInfo.getYAxis(0);
+
+        double ymin   = yAxis.getMin();
+        double ymax   = yAxis.getMax();
+        double yRange = ymax - ymin;
+
+        Transform2D transformer = getTransformer(0);
+
+        double[] start = transformer.transform(xrange[0], yrange[0]);
+        double[] end   = transformer.transform(xrange[1], yrange[1]);
+
+        zoom[2] = (start[1] - ymin) / yRange;
+        zoom[3] = (end[1] - ymin) / yRange;
+    }
+
+
     public void onPan(PanEvent event) {
-        if (transformer == null) {
+        if (chartInfo == null) {
             return;
         }
+
         int[] start = event.getStartPos();
         int[] end   = event.getEndPos();
 
-        double[] startPos = transformer.transform(start[0], start[1]);
-        double[] endPos   = transformer.transform(end[0], end[1]);
-
-        double diffX = startPos[0] - endPos[0];
-        double diffY = startPos[1] - endPos[1];
+        Transform2D t = getTransformer();
 
-        panTo(diffX, diffY);
-    }
-
+        double[] ts = t.transform(start[0], start[1]);
+        double[] tt = t.transform(end[0], end[1]);
 
-    /**
-     * This method pans to chart with a given factor.
-     */
-    public void panTo(double diffX, double diffY) {
+        double diffX = ts[0] - tt[0];
+        double diffY = ts[1] - tt[1];
+
         Axis xAxis = chartInfo.getXAxis(0);
         Axis yAxis = chartInfo.getYAxis(0);
 
-        xrange[0] = xAxis.getFrom() + diffX;
-        xrange[1] = xAxis.getTo() + diffX;
-        yrange[0] = yAxis.getFrom() + diffY;
-        yrange[1] = yAxis.getTo() + diffY;
+        double[] x = panAxis(xAxis, diffX);
+        double[] y = panAxis(yAxis, diffY);
 
-        updateTransformer();
+        zoom[0] = x[0];
+        zoom[1] = x[1];
+        zoom[2] = y[0];
+        zoom[3] = y[1];
+
+        updateChartInfo();
         updateChartPanel();
     }
 
 
+    protected double[] panAxis(Axis axis, double diff) {
+        double min = axis.getFrom();
+        double max = axis.getTo();
+
+        min += diff;
+        max += diff;
+
+        return computeZoom(axis, min, max);
+    }
+
+
     public void resetRanges() {
-        xrange[0] = 0;
-        xrange[1] = 0;
-        yrange[0] = 0;
-        yrange[1] = 0;
+        zoom[0] = 0d;
+        zoom[1] = 1d;
+        zoom[2] = 0d;
+        zoom[3] = 1d;
 
-        updateTransformer();
+        updateChartInfo();
         updateChartPanel();
     }
 
@@ -227,27 +293,58 @@
      * @param factor The factor should be between 0-100.
      */
     public void zoomOut(int factor) {
-        if (factor < 0 || factor > 100 || xrange == null || yrange == null) {
+        if (factor < 0 || factor > 100 || chartInfo == null) {
             return;
         }
 
-        double xadd = (xrange[1] - xrange[0]) / 100 * factor;
-        double yadd = (yrange[1] - yrange[0]) / 100 * factor;
+        Axis xAxis = chartInfo.getXAxis(0);
+        Axis yAxis = chartInfo.getYAxis(0);
 
-        xrange[0] -= xadd;
-        xrange[1] += xadd;
-        yrange[0] -= yadd;
-        yrange[1] += yadd;
+        double[] x = zoomAxis(xAxis, factor);
+        double[] y = zoomAxis(yAxis, factor);
 
-        updateTransformer();
+        zoom[0] = x[0];
+        zoom[1] = x[1];
+        zoom[2] = x[0];
+        zoom[3] = y[1];
+
+        updateChartInfo();
         updateChartPanel();
     }
 
 
+    public double[] zoomAxis(Axis axis, int factor) {
+        double min  = axis.getFrom();
+        double max  = axis.getTo();
+
+        double add = (max - min) / 100 * factor;
+        add = add < 0 ? (-1) * add : add;
+
+        min -= add;
+        max += add;
+
+        return computeZoom(axis, min, max);
+    }
+
+
+    public static double[] computeZoom(Axis axis, double min, double max) {
+        double[] zoom = new double[2];
+
+        double absMin = axis.getMin();
+        double absMax = axis.getMax();
+        double diff   = absMax > absMin ? absMax - absMin : absMin - absMax;
+
+        zoom[0] = (min - absMin) / diff;
+        zoom[1] = (max - absMin) / diff;
+
+        return zoom;
+    }
+
+
     /**
      * Updates the Transform2D object using the chart info service.
      */
-    public void updateTransformer() {
+    public void updateChartInfo() {
         Config config = Config.getInstance();
         String url    = config.getServerUrl();
         String locale = config.getLocale();
@@ -304,7 +401,15 @@
 
     protected void setChartInfo(ChartInfo chartInfo) {
         this.chartInfo = chartInfo;
-        setTransformer(chartInfo.getTransformer());
+    }
+
+
+    public Transform2D getTransformer() {
+        if (chartInfo == null) {
+            return null;
+        }
+
+        return chartInfo.getTransformer(0);
     }
 
 
@@ -312,21 +417,16 @@
      * Returns the Transform2D object used to transform image coordinates into
      * chart coordinates.
      *
+     * @param pos The index of a specific transformer.
+     *
      * @return the Transform2D object.
      */
-    public Transform2D getTransformer() {
-        return transformer;
-    }
-
+    public Transform2D getTransformer(int pos) {
+        if (chartInfo == null) {
+            return null;
+        }
 
-    /**
-     * Set a new Transform2D object for the chart. This should be the case, only
-     * if the chart image size has changed.
-     *
-     * @param transformer The new Transform2D object.
-     */
-    protected void setTransformer(Transform2D transformer) {
-        this.transformer = transformer;
+        return chartInfo.getTransformer(pos);
     }
 
 
@@ -393,16 +493,15 @@
         imgUrl += "&width=" + Integer.toString(width);
         imgUrl += "&height=" + Integer.toString(height);
 
-        if (xrange != null) {
-            GWT.log("Zoom to xrange.");
-            imgUrl += "&minx=" + Double.toString(xrange[0]);
-            imgUrl += "&maxx=" + Double.toString(xrange[1]);
-        }
+        double[] zoom = getZoomValues();
 
-        if (yrange != null) {
-            GWT.log("Zoom to xrange.");
-            imgUrl += "&miny=" + Double.toString(yrange[0]);
-            imgUrl += "&maxy=" + Double.toString(yrange[1]);
+        if (zoom != null) {
+            GWT.log("Zoom to specified range.");
+
+            imgUrl += "&minx=" + Double.toString(zoom[0]);
+            imgUrl += "&maxx=" + Double.toString(zoom[1]);
+            imgUrl += "&miny=" + Double.toString(zoom[2]);
+            imgUrl += "&maxy=" + Double.toString(zoom[3]);
         }
 
         return imgUrl;
@@ -416,17 +515,21 @@
         attr.put("width", chart.getWidth().toString());
         attr.put("height", chart.getHeight().toString());
 
-        if (xrange != null) {
-            attr.put("minx", Double.toString(xrange[0]));
-            attr.put("maxx", Double.toString(xrange[1]));
-        }
+        double[] zoom = getZoomValues();
 
-        if (yrange != null) {
-            attr.put("miny", Double.toString(yrange[0]));
-            attr.put("maxy", Double.toString(yrange[1]));
+        if (zoom != null) {
+            attr.put("minx", Double.toString(zoom[0]));
+            attr.put("maxx", Double.toString(zoom[1]));
+            attr.put("miny", Double.toString(zoom[2]));
+            attr.put("maxy", Double.toString(zoom[3]));
         }
 
         return attr;
     }
+
+
+    protected double[] getZoomValues() {
+        return zoom;
+    }
 }
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