Zoom with scrollwheel in Traceview.

The zoom factor is 2 (hardcoded).
The fixed point is given by the mouse position when zooming in.
When zooming out, we use the previous fixed point.
This commit do not launch an animation when zooming.

Change-Id: I020cce5ff12f80e70a49510dc334a250c23616ae

1 files changed, 48 insertions, 2 deletions

diff --git a/traceview/src/com/android/traceview/TimeLineView.java b/traceview/src/com/android/traceview/TimeLineView.java
index 875becf..bc565dd 100644
--- a/traceview/src/com/android/traceview/TimeLineView.java
+++ b/traceview/src/com/android/traceview/TimeLineView.java
@@ -22,6 +22,7 @@ import org.eclipse.swt.custom.SashForm;
 import org.eclipse.swt.events.MouseAdapter;
 import org.eclipse.swt.events.MouseEvent;
 import org.eclipse.swt.events.MouseMoveListener;
+import org.eclipse.swt.events.MouseWheelListener;
 import org.eclipse.swt.events.PaintEvent;
 import org.eclipse.swt.events.PaintListener;
 import org.eclipse.swt.graphics.Color;
@@ -284,6 +285,12 @@ public class TimeLineView extends Composite implements Observer {
             }
         });
 
+        mSurface.addMouseWheelListener(new MouseWheelListener() {
+            public void mouseScrolled(MouseEvent me) {
+                mSurface.mouseScrolled(me);
+            }
+        });
+
         mTimescale.addMouseListener(new MouseAdapter() {
             @Override
             public void mouseUp(MouseEvent me) {
@@ -842,7 +849,7 @@ public class TimeLineView extends Composite implements Observer {
     }
 
     private static enum GraphicsState {
-        Normal, Marking, Scaling, Animating
+        Normal, Marking, Scaling, Animating, Scrolling
     };
 
     private class Surface extends Canvas {
@@ -966,7 +973,8 @@ public class TimeLineView extends Composite implements Observer {
                 int xdim = dim.x - TotalXMargin;
                 mScaleInfo.setNumPixels(xdim);
                 boolean forceEndPoints = (mGraphicsState == GraphicsState.Scaling
-                        || mGraphicsState == GraphicsState.Animating);
+                        || mGraphicsState == GraphicsState.Animating
+                        || mGraphicsState == GraphicsState.Scrolling);
                 mScaleInfo.computeTicks(forceEndPoints);
                 mCachedMinVal = mScaleInfo.getMinVal();
                 mCachedMaxVal = mScaleInfo.getMaxVal();
@@ -1687,6 +1695,44 @@ public class TimeLineView extends Composite implements Observer {
             update();
         }
 
+        private void mouseScrolled(MouseEvent me) {
+            mGraphicsState = GraphicsState.Scrolling;
+            double tMin = mScaleInfo.getMinVal();
+            double tMax = mScaleInfo.getMaxVal();
+            double zoomFactor = 2;
+            double tMinRef = mLimitMinVal;
+            double tMaxRef = mLimitMaxVal;
+            double t; // the fixed point
+            double tMinNew;
+            double tMaxNew;
+            if (me.count > 0) {
+                // we zoom in
+                Point dim = mSurface.getSize();
+                int x = me.x;
+                if (x < LeftMargin)
+                    x = LeftMargin;
+                if (x > dim.x - RightMargin)
+                    x = dim.x - RightMargin;
+                double ppr = mScaleInfo.getPixelsPerRange();
+                t = tMin + ((x - LeftMargin) / ppr);
+                tMinNew = Math.max(tMinRef, t - (t - tMin) / zoomFactor);
+                tMaxNew = Math.min(tMaxRef, t + (tMax - t) / zoomFactor);
+            } else {
+                // we zoom out
+                double factor = (tMax - tMin) / (tMaxRef - tMinRef);
+                if (factor < 1) {
+                    t = (factor * tMinRef - tMin) / (factor - 1);
+                    tMinNew = Math.max(tMinRef, t - zoomFactor * (t - tMin));
+                    tMaxNew = Math.min(tMaxRef, t + zoomFactor * (tMax - t));
+                } else {
+                    return;
+                }
+            }
+            mScaleInfo.setMinVal(tMinNew);
+            mScaleInfo.setMaxVal(tMaxNew);
+            mSurface.redraw();
+        }
+
         // No defined behavior yet for double-click.
         private void mouseDoubleClick(MouseEvent me) {
         }