New zoom control for phone.

bug:5318964

+update assets

Change-Id: I39c6575803d22ab5db5c75a2d47257d12a397255

12 files changed, 152 insertions, 126 deletions

diff --git a/src/com/android/camera/Camera.java b/src/com/android/camera/Camera.java
index 5c645a4..1274a72 100644
--- a/src/com/android/camera/Camera.java
+++ b/src/com/android/camera/Camera.java
@@ -460,7 +460,8 @@ public class Camera extends ActivityBase implements FocusManager.Listener,
     private void initializeZoom() {
         if (!mParameters.isZoomSupported()) return;
         mZoomMax = mParameters.getMaxZoom();
-        mSmoothZoomSupported = mParameters.isSmoothZoomSupported();
+        // Currently we use immediate zoom for fast zooming to get better UX and
+        // there is no plan to take advantage of the smooth zoom.
         mZoomControl.setZoomMax(mZoomMax);
         mZoomControl.setZoomIndex(mParameters.getZoom());
         mZoomControl.setSmoothZoomSupported(mSmoothZoomSupported);
@@ -938,6 +939,7 @@ public class Camera extends ActivityBase implements FocusManager.Listener,
         if (mIndicatorControlContainer == null) return;
         loadCameraPreferences();
         final String[] SETTING_KEYS = {
+                CameraSettings.KEY_FLASH_MODE,
                 CameraSettings.KEY_WHITE_BALANCE,
                 CameraSettings.KEY_SCENE_MODE};
         final String[] OTHER_SETTING_KEYS = {
@@ -948,7 +950,7 @@ public class Camera extends ActivityBase implements FocusManager.Listener,
 
         CameraPicker.setImageResourceId(R.drawable.ic_switch_photo_facing_holo_light);
         mIndicatorControlContainer.initialize(this, mPreferenceGroup,
-                CameraSettings.KEY_FLASH_MODE, mParameters.isZoomSupported(),
+                mParameters.isZoomSupported(),
                 SETTING_KEYS, OTHER_SETTING_KEYS);
         mIndicatorControlContainer.setListener(this);
     }
diff --git a/src/com/android/camera/VideoCamera.java b/src/com/android/camera/VideoCamera.java
index e9c3133..f100d28 100644
--- a/src/com/android/camera/VideoCamera.java
+++ b/src/com/android/camera/VideoCamera.java
@@ -469,6 +469,7 @@ public class VideoCamera extends ActivityBase
         loadCameraPreferences();
 
         final String[] SETTING_KEYS = {
+                    CameraSettings.KEY_VIDEOCAMERA_FLASH_MODE,
                     CameraSettings.KEY_VIDEO_EFFECT,
                     CameraSettings.KEY_WHITE_BALANCE,
                     CameraSettings.KEY_VIDEO_QUALITY};
@@ -477,7 +478,6 @@ public class VideoCamera extends ActivityBase
 
         CameraPicker.setImageResourceId(R.drawable.ic_switch_video_facing_holo_light);
         mIndicatorControlContainer.initialize(this, mPreferenceGroup,
-                CameraSettings.KEY_VIDEOCAMERA_FLASH_MODE,
                 mParameters.isZoomSupported(), SETTING_KEYS, OTHER_SETTING_KEYS);
         mIndicatorControlContainer.setListener(this);
         mPopupGestureDetector = new GestureDetector(this,
@@ -2108,7 +2108,8 @@ public class VideoCamera extends ActivityBase
         if (!mParameters.isZoomSupported()) return;
 
         mZoomMax = mParameters.getMaxZoom();
-        mSmoothZoomSupported = mParameters.isSmoothZoomSupported();
+        // Currently we use immediate zoom for fast zooming to get better UX and
+        // there is no plan to take advantage of the smooth zoom.
         mZoomControl.setZoomMax(mZoomMax);
         mZoomControl.setZoomIndex(mParameters.getZoom());
         mZoomControl.setSmoothZoomSupported(mSmoothZoomSupported);
diff --git a/src/com/android/camera/ui/IndicatorControl.java b/src/com/android/camera/ui/IndicatorControl.java
index 78d51c1..4bc5d29 100644
--- a/src/com/android/camera/ui/IndicatorControl.java
+++ b/src/com/android/camera/ui/IndicatorControl.java
@@ -70,6 +70,8 @@ public abstract class IndicatorControl extends RelativeLayout implements
             View view = getChildAt(i);
             if (view instanceof RotateImageView) {
                 ((RotateImageView) view).setDegree(degree);
+            } else if (view instanceof ZoomControl) {
+                ((ZoomControl) view).setDegree(degree);
             }
         }
     }
diff --git a/src/com/android/camera/ui/IndicatorControlBar.java b/src/com/android/camera/ui/IndicatorControlBar.java
index c1e6607..4297528 100644
--- a/src/com/android/camera/ui/IndicatorControlBar.java
+++ b/src/com/android/camera/ui/IndicatorControlBar.java
@@ -30,7 +30,7 @@ import android.widget.ImageView;
  * A view that contains the top-level indicator control.
  */
 public class IndicatorControlBar extends IndicatorControl implements
-        View.OnClickListener, View.OnTouchListener {
+        View.OnClickListener {
     private static final String TAG = "IndicatorControlBar";
 
     // Space between indicator icons.
@@ -38,6 +38,7 @@ public class IndicatorControlBar extends IndicatorControl implements
 
     private ImageView mZoomIcon;
     private ImageView mSecondLevelIcon;
+    private ZoomControlBar mZoomControl;
 
     public IndicatorControlBar(Context context, AttributeSet attrs) {
         super(context, attrs);
@@ -45,27 +46,23 @@ public class IndicatorControlBar extends IndicatorControl implements
 
     @Override
     protected void onFinishInflate() {
-        mZoomIcon = (ImageView) findViewById(R.id.zoom_control_icon);
         mSecondLevelIcon = (ImageView)
                 findViewById(R.id.second_level_indicator_bar_icon);
         mSecondLevelIcon.setOnClickListener(this);
     }
 
     public void initialize(Context context, PreferenceGroup group,
-            String flashSetting, boolean zoomSupported) {
-        // From UI spec, we have camera_flash setting on the first level.
+            boolean zoomSupported) {
         setPreferenceGroup(group);
-        addControls(new String[] {flashSetting}, null);
 
         // Add CameraPicker control.
         initializeCameraPicker();
 
-        // add Zoom Icon.
+        // Add the ZoomControl if supported.
         if (zoomSupported) {
-            mZoomIcon.setOnTouchListener(this);
-            mZoomIcon.setVisibility(View.VISIBLE);
+            mZoomControl = (ZoomControlBar) findViewById(R.id.zoom_control);
+            mZoomControl.setVisibility(View.VISIBLE);
         }
-
         requestLayout();
     }
 
@@ -76,15 +73,6 @@ public class IndicatorControlBar extends IndicatorControl implements
         return true;
     }
 
-    public boolean onTouch(View v, MotionEvent event) {
-        dismissSettingPopup();
-        if (event.getAction() == MotionEvent.ACTION_DOWN) {
-            mOnIndicatorEventListener.onIndicatorEvent(
-                    OnIndicatorEventListener.EVENT_ENTER_ZOOM_CONTROL);
-        }
-        return true;
-    }
-
     public void onClick(View view) {
         dismissSettingPopup();
         // Only for the click on mSecondLevelIcon.
@@ -96,21 +84,25 @@ public class IndicatorControlBar extends IndicatorControl implements
     protected void onLayout(
             boolean changed, int left, int top, int right, int bottom) {
         // Layout the static components.
+        int padding = getPaddingTop();
         super.onLayout(changed, left, top, right, bottom);
 
         int count = getChildCount();
         if (count == 0) return;
         int width = right - left;
-        int offset = 0;
-
-        for (int i = 0 ; i < count ; i++) {
-            View view = getChildAt(i);
-            if (view instanceof IndicatorButton) {
-                view.layout(0, offset, width, offset + width);
-                offset += (width + ICON_SPACING);
-            }
+
+        // First indicator will be CameraPicker if exists.
+        if (mCameraPicker != null) {
+            mCameraPicker.layout(0, padding, width, padding + width);
         }
-        if (mCameraPicker != null) mCameraPicker.layout(0, offset, width, offset + width);
+
+        // Layout the zoom control if required.
+        int offset = padding + width; // the padding and the icon height
+        if (mZoomControl != null)  {
+            mZoomControl.layout(0, offset, width, bottom - top - offset);
+        }
+
+        mSecondLevelIcon.layout(0, bottom - top - offset, width, bottom - top);
     }
 
     @Override
@@ -126,6 +118,6 @@ public class IndicatorControlBar extends IndicatorControl implements
     }
 
     public void enableZoom(boolean enabled) {
-        if (mZoomIcon != null)  mZoomIcon.setEnabled(enabled);
+        if (mZoomControl != null)  mZoomControl.setEnabled(enabled);
     }
 }
diff --git a/src/com/android/camera/ui/IndicatorControlBarContainer.java b/src/com/android/camera/ui/IndicatorControlBarContainer.java
index 60eb6b2..9c01e01 100644
--- a/src/com/android/camera/ui/IndicatorControlBarContainer.java
+++ b/src/com/android/camera/ui/IndicatorControlBarContainer.java
@@ -39,8 +39,6 @@ public class IndicatorControlBarContainer extends IndicatorControlContainer
     private Animation mFadeIn, mFadeOut;
     private Animation mSecondLevelFadeIn, mSecondLevelFadeOut;
     private IndicatorControlBar mIndicatorControlBar;
-    private ZoomControlBar mZoomControlBar;
-    private ZoomIndexBar mZoomIndexBar;
     private SecondLevelIndicatorControlBar mSecondLevelIndicatorControlBar;
 
     public IndicatorControlBarContainer(Context context, AttributeSet attrs) {
@@ -59,10 +57,6 @@ public class IndicatorControlBarContainer extends IndicatorControlContainer
 
     @Override
     protected void onFinishInflate() {
-        mZoomControlBar = (ZoomControlBar) findViewById(R.id.zoom_control);
-        mZoomControlBar.setOnIndicatorEventListener(this);
-        mZoomIndexBar = (ZoomIndexBar) findViewById(R.id.zoom_index_bar);
-        mZoomControlBar.setOnZoomIndexChangeListener(mZoomIndexBar);
         mIndicatorControlBar = (IndicatorControlBar)
                 findViewById(R.id.indicator_bar);
         mIndicatorControlBar.setOnIndicatorEventListener(this);
@@ -73,13 +67,10 @@ public class IndicatorControlBarContainer extends IndicatorControlContainer
 
     @Override
     public void initialize(Context context, PreferenceGroup group,
-            String flashSetting, boolean isZoomSupported,
-            String[] secondLevelKeys, String[] secondLevelOtherSettingKeys) {
+            boolean isZoomSupported, String[] secondLevelKeys,
+            String[] secondLevelOtherSettingKeys) {
 
-        // We need to show/hide the zoom slider icon accordingly.
-        // From UI spec, we have camera_flash setting on the first level.
-        mIndicatorControlBar.initialize(context, group, flashSetting,
-                isZoomSupported);
+        mIndicatorControlBar.initialize(context, group, isZoomSupported);
 
         mSecondLevelIndicatorControlBar.initialize(context, group,
                 secondLevelKeys, secondLevelOtherSettingKeys);
@@ -88,8 +79,6 @@ public class IndicatorControlBarContainer extends IndicatorControlContainer
     public void setDegree(int degree) {
         mIndicatorControlBar.setDegree(degree);
         mSecondLevelIndicatorControlBar.setDegree(degree);
-        mZoomControlBar.setDegree(degree);
-        mZoomIndexBar.setDegree(degree);
     }
 
     @Override
@@ -98,8 +87,6 @@ public class IndicatorControlBarContainer extends IndicatorControlContainer
             return mIndicatorControlBar.dispatchTouchEvent(event);
         } else if (mSecondLevelIndicatorControlBar.getVisibility() == View.VISIBLE) {
             return mSecondLevelIndicatorControlBar.dispatchTouchEvent(event);
-        } else if (mZoomControlBar.getVisibility() == View.VISIBLE) {
-            return mZoomControlBar.dispatchTouchEvent(event);
         }
         return true;
     }
@@ -133,19 +120,6 @@ public class IndicatorControlBarContainer extends IndicatorControlContainer
                 mIndicatorControlBar.setVisibility(View.VISIBLE);
                 mSecondLevelIndicatorControlBar.startAnimation(mSecondLevelFadeOut);
                 break;
-
-            case OnIndicatorEventListener.EVENT_ENTER_ZOOM_CONTROL:
-                mIndicatorControlBar.setVisibility(View.GONE);
-                mZoomControlBar.setVisibility(View.VISIBLE);
-                mZoomIndexBar.setVisibility(View.VISIBLE);
-                mZoomControlBar.startZoomControl();
-                break;
-
-            case OnIndicatorEventListener.EVENT_LEAVE_ZOOM_CONTROL:
-                mZoomControlBar.setVisibility(View.GONE);
-                mZoomIndexBar.setVisibility(View.GONE);
-                mIndicatorControlBar.setVisibility(View.VISIBLE);
-                break;
         }
     }
 
diff --git a/src/com/android/camera/ui/IndicatorControlContainer.java b/src/com/android/camera/ui/IndicatorControlContainer.java
index 552c551..3f66acb 100644
--- a/src/com/android/camera/ui/IndicatorControlContainer.java
+++ b/src/com/android/camera/ui/IndicatorControlContainer.java
@@ -23,8 +23,7 @@ import android.util.AttributeSet;
 
 public abstract class IndicatorControlContainer extends IndicatorControl {
     public abstract void initialize(Context context, PreferenceGroup group,
-            String flashSetting, boolean isZoomSupported,
-            String[] keys, String[] otherSettingKeys);
+            boolean isZoomSupported, String[] keys, String[] otherSettingKeys);
 
     public IndicatorControlContainer(Context context, AttributeSet attrs) {
         super(context, attrs);
diff --git a/src/com/android/camera/ui/IndicatorControlWheel.java b/src/com/android/camera/ui/IndicatorControlWheel.java
index f3f869a..af36e11 100644
--- a/src/com/android/camera/ui/IndicatorControlWheel.java
+++ b/src/com/android/camera/ui/IndicatorControlWheel.java
@@ -146,17 +146,13 @@ public class IndicatorControlWheel extends IndicatorControl implements
     }
 
     public void initialize(Context context, PreferenceGroup group,
-            String flashSetting, boolean isZoomSupported, String[] keys,
-            String[] otherSettingKeys) {
+            boolean isZoomSupported, String[] keys, String[] otherSettingKeys) {
         mShutterButtonRadius = IndicatorControlWheelContainer.SHUTTER_BUTTON_RADIUS;
         mStrokeWidth = Util.dpToPixel(IndicatorControlWheelContainer.STROKE_WIDTH);
         mWheelRadius = mShutterButtonRadius + mStrokeWidth * 0.5;
 
         setPreferenceGroup(group);
 
-        // Add first-level controls.
-        addControls(new String[] {flashSetting}, null);
-
         // Add Zoom Icon.
         if (isZoomSupported) {
             mZoomIcon = (ImageView) addImageButton(context, R.drawable.ic_zoom_holo_light, false);
diff --git a/src/com/android/camera/ui/IndicatorControlWheelContainer.java b/src/com/android/camera/ui/IndicatorControlWheelContainer.java
index 4e2a03e..664aa9b 100644
--- a/src/com/android/camera/ui/IndicatorControlWheelContainer.java
+++ b/src/com/android/camera/ui/IndicatorControlWheelContainer.java
@@ -62,10 +62,9 @@ public class IndicatorControlWheelContainer extends IndicatorControlContainer
     }
 
     public void initialize(Context context, PreferenceGroup group,
-            String flashSetting, boolean isZoomSupported,
-            String[] keys, String[] otherSettingKeys) {
-        mIndicatorControlWheel.initialize(context, group, flashSetting,
-                isZoomSupported, keys, otherSettingKeys);
+            boolean isZoomSupported, String[] keys, String[] otherSettingKeys) {
+        mIndicatorControlWheel.initialize(context, group, isZoomSupported,
+                keys, otherSettingKeys);
         mIndicatorControlWheel.setOnIndicatorEventListener(this);
     }
 
diff --git a/src/com/android/camera/ui/SecondLevelIndicatorControlBar.java b/src/com/android/camera/ui/SecondLevelIndicatorControlBar.java
index 386179d..bfa9f94 100644
--- a/src/com/android/camera/ui/SecondLevelIndicatorControlBar.java
+++ b/src/com/android/camera/ui/SecondLevelIndicatorControlBar.java
@@ -33,7 +33,7 @@ import android.widget.ImageView;
 public class SecondLevelIndicatorControlBar extends IndicatorControl implements
         View.OnClickListener {
     private static final String TAG = "SecondLevelIndicatorControlBar";
-    private static int ICON_SPACING = Util.dpToPixel(32);
+    private static int ICON_SPACING = Util.dpToPixel(24);
     private ImageView mCloseIcon;
     private View mDivider; // the divider line
     int mDegree = 0;
diff --git a/src/com/android/camera/ui/ZoomControl.java b/src/com/android/camera/ui/ZoomControl.java
index be2bdb9..662ee92 100644
--- a/src/com/android/camera/ui/ZoomControl.java
+++ b/src/com/android/camera/ui/ZoomControl.java
@@ -20,6 +20,7 @@ import com.android.camera.R;
 
 import android.content.Context;
 import android.os.Handler;
+import android.os.SystemClock;
 import android.util.AttributeSet;
 import android.view.View;
 import android.widget.ImageView;
@@ -30,16 +31,20 @@ import android.widget.RelativeLayout;
  * if the camera supports zooming.
  */
 public abstract class ZoomControl extends RelativeLayout {
-    private static final String TAG = "ZoomControl";
+    // The states of zoom button.
+    public static final int ZOOM_IN = 0;
+    public static final int ZOOM_OUT = 1;
+    public static final int ZOOM_STOP = 2;
 
-    public static final int ZOOMING_INTERVAL = 300; // milliseconds
+    private static final String TAG = "ZoomControl";
+    private static final int ZOOMING_INTERVAL = 1000; // milliseconds
 
     protected ImageView mZoomIn;
     protected ImageView mZoomOut;
     protected ImageView mZoomSlider;
     protected int mSliderPosition = 0;
     protected int mDegree;
-    protected Handler mHandler;
+    private Handler mHandler;
 
     public interface OnZoomChangedListener {
         void onZoomValueChanged(int index);  // only for immediate zoom
@@ -58,23 +63,13 @@ public abstract class ZoomControl extends RelativeLayout {
     private OnZoomChangedListener mListener;
     private OnZoomIndexChangedListener mIndexListener;
 
-    // The state of zoom button.
-    public static final int ZOOM_IN = 0;
-    public static final int ZOOM_OUT = 1;
-    public static final int ZOOM_STOP = 2;
-
     protected OnIndicatorEventListener mOnIndicatorEventListener;
+    private int mState;
+    private int mStep;
 
     protected final Runnable mRunnable = new Runnable() {
         public void run() {
-            if (mSliderPosition < 0) {
-                zoomIn();
-            } else if (mSliderPosition > 0) {
-                zoomOut();
-            } else {
-                stopZooming();
-            }
-            mHandler.postDelayed(mRunnable, ZOOMING_INTERVAL);
+            performZoom(mState, false);
         }
     };
 
@@ -88,7 +83,6 @@ public abstract class ZoomControl extends RelativeLayout {
 
     public void startZoomControl() {
         mZoomSlider.setPressed(true);
-        mHandler.postDelayed(mRunnable, ZOOMING_INTERVAL);
         setZoomIndex(mZoomIndex); // Update the zoom index bar.
     }
 
@@ -100,12 +94,13 @@ public abstract class ZoomControl extends RelativeLayout {
     }
 
     public void closeZoomControl() {
-        mHandler.removeCallbacks(mRunnable);
-        mSliderPosition = 0;
         mZoomSlider.setPressed(false);
         stopZooming();
-        mOnIndicatorEventListener.onIndicatorEvent(
-                OnIndicatorEventListener.EVENT_LEAVE_ZOOM_CONTROL);
+        if (!mSmoothZoomSupported) mHandler.removeCallbacks(mRunnable);
+        if (mOnIndicatorEventListener != null) {
+            mOnIndicatorEventListener.onIndicatorEvent(
+                    OnIndicatorEventListener.EVENT_LEAVE_ZOOM_CONTROL);
+        }
     }
 
     public void setZoomMax(int zoomMax) {
@@ -143,30 +138,71 @@ public abstract class ZoomControl extends RelativeLayout {
         mSmoothZoomSupported = smoothZoomSupported;
     }
 
-    public boolean zoomIn() {
-        return (mZoomIndex == mZoomMax) ? false : changeZoomIndex(mZoomIndex + 1);
+    private boolean zoomIn() {
+        return (mZoomIndex == mZoomMax) ? false : changeZoomIndex(mZoomIndex + mStep);
+    }
+
+    private boolean zoomOut() {
+        return (mZoomIndex == 0) ? false : changeZoomIndex(mZoomIndex - mStep);
     }
 
-    public boolean zoomOut() {
-        return (mZoomIndex == 0) ? false : changeZoomIndex(mZoomIndex - 1);
+    protected void setZoomStep(int step) {
+        mStep = step;
     }
 
-    public void stopZooming() {
+    private void stopZooming() {
         if (mSmoothZoomSupported) {
             if (mListener != null) mListener.onZoomStateChanged(ZOOM_STOP);
         }
     }
 
+    // Called from ZoomControlWheel to change the zoom level.
+    // TODO: merge the zoom control for both platforms.
+    protected void performZoom(int state) {
+        performZoom(state, true);
+    }
+
+    private void performZoom(int state, boolean fromUser) {
+        if ((mState == state) && fromUser) return;
+        if (fromUser) mHandler.removeCallbacks(mRunnable);
+        mState = state;
+        switch (state) {
+            case ZOOM_IN:
+                zoomIn();
+                break;
+            case ZOOM_OUT:
+                zoomOut();
+                break;
+            case ZOOM_STOP:
+                stopZooming();
+                break;
+        }
+        if (!mSmoothZoomSupported) {
+            // Repeat the zoom action on tablet as the user is still holding
+            // the zoom slider.
+            mHandler.postDelayed(mRunnable, ZOOMING_INTERVAL / mZoomMax);
+        }
+    }
+
+    // Called from ZoomControlBar to change the zoom level.
+    protected void performZoom(double zoomPercentage) {
+        int index = (int) (mZoomMax * zoomPercentage);
+        if (mZoomIndex == index) return;
+        changeZoomIndex(index);
+   }
+
     private boolean changeZoomIndex(int index) {
-        int zoomType = (index < mZoomIndex) ? ZOOM_OUT : ZOOM_IN;
         if (mListener != null) {
             if (mSmoothZoomSupported) {
+                int zoomType = (index < mZoomIndex) ? ZOOM_OUT : ZOOM_IN;
                 if (((zoomType == ZOOM_IN) && (mZoomIndex != mZoomMax)) ||
                         ((zoomType == ZOOM_OUT) && (mZoomIndex != 0))) {
                     mListener.onZoomStateChanged(zoomType);
                 }
             } else {
-                mListener.onZoomStateChanged(index);
+                if (index > mZoomMax) index = mZoomMax;
+                if (index < 0) index = 0;
+                mListener.onZoomValueChanged(index);
                 setZoomIndex(index);
             }
         }
diff --git a/src/com/android/camera/ui/ZoomControlBar.java b/src/com/android/camera/ui/ZoomControlBar.java
index d906dea..6bbb8f1 100644
--- a/src/com/android/camera/ui/ZoomControlBar.java
+++ b/src/com/android/camera/ui/ZoomControlBar.java
@@ -20,6 +20,7 @@ import com.android.camera.R;
 import com.android.camera.Util;
 
 import android.content.Context;
+import android.os.Handler;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.View;
@@ -29,9 +30,9 @@ import android.view.View;
  */
 public class ZoomControlBar extends ZoomControl {
     private static final String TAG = "ZoomControlBar";
-    private static final int STOP_ZOOM_BUFFER = Util.dpToPixel(30);
-
+    private static int THRESHOLD_FIRST_MOVE = Util.dpToPixel(10); // pixels
     private View mBar;
+    private boolean mStartChanging;
 
     public ZoomControlBar(Context context, AttributeSet attrs) {
         super(context, attrs);
@@ -49,29 +50,42 @@ public class ZoomControlBar extends ZoomControl {
         if (!isEnabled()) return false;
 
         double y = (double) event.getY();
-        int offset = getHeight() / 2;
 
+        // Calculate the absolute offset of the slider in the zoom control bar.
         // For left-hand users, as the device is rotated for 180 degree for
         // landscape mode, the zoom-in bottom should be on the top, so the
         // position should be reversed.
-        int delta;
+        int offset = 5 * getWidth() / 4; // the padding and the icon height
+        int height = getHeight();
+        int range = height - 2 * offset; // the range of the zoom slider
+        int pos; // the relative position in the zoom slider bar
         if (mDegree == 180) {
-            delta = offset - (int) y;
+            pos = (int) y - offset;
         } else {
-            delta = (int) y - offset;
+            pos = height - (int) y - offset;
         }
-        // We need some space to stop zooming.
-        mSliderPosition = (Math.abs(delta) < STOP_ZOOM_BUFFER) ? 0 : delta;
-
-        // TODO: add fast zoom change here
+        if (pos < 0) pos = 0;
+        if (pos > range) pos = range;
 
         switch (action) {
             case MotionEvent.ACTION_OUTSIDE:
-            case MotionEvent.ACTION_UP:
             case MotionEvent.ACTION_CANCEL:
                 closeZoomControl();
                 break;
-            default:
+
+            case MotionEvent.ACTION_DOWN:
+                mStartChanging = false;
+            case MotionEvent.ACTION_MOVE:
+                // Make sure the movement is large enough before we start
+                // changing the zoom.
+                if (!mStartChanging && (Math.abs(mSliderPosition - pos)
+                        > THRESHOLD_FIRST_MOVE)) {
+                    mStartChanging = true;
+                }
+                if (mStartChanging) {
+                    performZoom(1.0d * pos / range);
+                    mSliderPosition = pos;
+                }
                 requestLayout();
         }
         return true;
@@ -87,30 +101,29 @@ public class ZoomControlBar extends ZoomControl {
     @Override
     protected void onLayout(
             boolean changed, int left, int top, int right, int bottom) {
+        if (mZoomMax == 0) return;
+
         int width = right - left;
         int height = bottom - top;
-        int h = height / 2;
+        int range = height - 10 * width / 4;
         int pos;
 
+        // TODO: remove offset once we have correct ic_zoom_big.9.png.
+        int offset = 3 * width / 4;
+
         // For left-hand users, as the device is rotated for 180 degree,
         // the zoom-in button should be on the top.
         if (mDegree == 180) {
-            pos = h - mSliderPosition - width / 2;
             mZoomOut.layout(0, 0, width, width);
             mZoomIn.layout(0, height - width, width, height);
+            pos = offset + mZoomIndex * range / mZoomMax;
+            mZoomSlider.layout(0, pos, width, pos + width);
         } else {
-            pos = h + mSliderPosition - width / 2;
             mZoomIn.layout(0, 0, width, width);
             mZoomOut.layout(0, height - width, width, height);
+            pos = offset + (mZoomMax - mZoomIndex) * range / mZoomMax;
+            mZoomSlider.layout(0, pos, width, pos + width);
         }
-        mBar.layout(0, width, width, height - width);
-
-        // TODO: fix the pos once we have correct zoom_big asset.
-        if (pos < 3 * width / 4) {
-            pos = 3 * width / 4;
-        } else if (pos > (height - (7 * width / 4))) {
-            pos = height - (7 * width / 4);
-        }
-        mZoomSlider.layout(0, pos, width, pos + width);
+        mBar.layout(0, width, width, bottom - top - width);
     }
 }
diff --git a/src/com/android/camera/ui/ZoomControlWheel.java b/src/com/android/camera/ui/ZoomControlWheel.java
index bb70ddf..6a75097 100644
--- a/src/com/android/camera/ui/ZoomControlWheel.java
+++ b/src/com/android/camera/ui/ZoomControlWheel.java
@@ -75,6 +75,17 @@ public class ZoomControlWheel extends ZoomControl {
         mShutterButtonRadius = IndicatorControlWheelContainer.SHUTTER_BUTTON_RADIUS;
         mStrokeWidth = Util.dpToPixel(IndicatorControlWheelContainer.STROKE_WIDTH);
         mWheelRadius = mShutterButtonRadius + mStrokeWidth * 0.5;
+        super.setZoomStep(1); // one zoom level at a time
+    }
+
+    private void performZoom() {
+        if (mSliderRadians > (Math.PI + BUFFER_RADIANS)) {
+            super.performZoom(ZOOM_OUT);
+        } else if (mSliderRadians < (Math.PI - BUFFER_RADIANS)) {
+            super.performZoom(ZOOM_IN);
+        } else {
+            super.performZoom(ZOOM_STOP);
+        }
     }
 
     @Override
@@ -102,7 +113,8 @@ public class ZoomControlWheel extends ZoomControl {
             case MotionEvent.ACTION_CANCEL:
                 closeZoomControl();
                 break;
-            default:
+            case MotionEvent.ACTION_MOVE:
+                performZoom();
                 requestLayout();
         }
         return true;