Added ViewportChangeListener

hellocharts-library/src/lecho/lib/hellocharts/Chart.java

@@ -30,6 +30,8 @@ public interface Chart {
 
 	public void setViewportAnimationListener(ChartAnimationListener animationListener);
 
+	public void setViewportChangeListener(ViewportChangeListener viewportChangeListener);
+
 	public void callTouchListener(SelectedValue selectedValue);
 
 	public boolean isInteractive();

hellocharts-library/src/lecho/lib/hellocharts/ChartCalculator.java

@@ -29,6 +29,8 @@ public class ChartCalculator {
 	protected float minViewportWidth;
 	protected float minViewportHeight;
 
+	private ViewportChangeListener viewportChangeListener = new DummyVieportChangeListener();
+
 	/**
 	 * Calculates available width and height. Should be called when chart dimensions or chart data change.
 	 */
@@ -72,6 +74,8 @@ public void constrainViewport(float left, float top, float right, float bottom)
 		currentViewport.top = Math.max(maxViewport.top, top);
 		currentViewport.bottom = Math.max(Utils.nextUpF(top), Math.min(maxViewport.bottom, bottom));
 		currentViewport.right = Math.max(Utils.nextUpF(left), Math.min(maxViewport.right, right));
+
+		viewportChangeListener.onViewportChanged(currentViewport);
 	}
 
 	/**
@@ -183,4 +187,12 @@ public float getMinimumViewportHeight() {
 		return minViewportHeight;
 	}
 
+	public void setViewportChangeListener(ViewportChangeListener viewportChangeListener) {
+		if (null == viewportChangeListener) {
+			this.viewportChangeListener = new DummyVieportChangeListener();
+		} else {
+			this.viewportChangeListener = viewportChangeListener;
+		}
+	}
+
 }

hellocharts-library/src/lecho/lib/hellocharts/DummyVieportChangeListener.java

@@ -0,0 +1,12 @@
+package lecho.lib.hellocharts;
+
+import android.graphics.RectF;
+import android.util.Log;
+
+public class DummyVieportChangeListener implements ViewportChangeListener {
+
+	@Override
+	public void onViewportChanged(RectF newViewport) {
+		// Do nothing
+	}
+}

hellocharts-library/src/lecho/lib/hellocharts/ViewportChangeListener.java

@@ -0,0 +1,9 @@
+package lecho.lib.hellocharts;
+
+import android.graphics.RectF;
+
+public interface ViewportChangeListener {
+
+	public void onViewportChanged(RectF newViewport);
+
+}

hellocharts-library/src/lecho/lib/hellocharts/view/AbstractChartView.java

@@ -2,6 +2,7 @@
 
 import lecho.lib.hellocharts.Chart;
 import lecho.lib.hellocharts.ChartCalculator;
+import lecho.lib.hellocharts.ViewportChangeListener;
 import lecho.lib.hellocharts.anim.ChartAnimationListener;
 import lecho.lib.hellocharts.anim.ChartDataAnimator;
 import lecho.lib.hellocharts.anim.ChartDataAnimatorV14;
@@ -107,6 +108,11 @@ public void setViewportAnimationListener(ChartAnimationListener animationListene
 		viewportAnimator.setChartAnimationListener(animationListener);
 	}
 
+	@Override
+	public void setViewportChangeListener(ViewportChangeListener viewportChangeListener) {
+		chartCalculator.setViewportChangeListener(viewportChangeListener);
+	}
+
 	public ChartRenderer getChartRenderer() {
 		return chartRenderer;
 	}