Refactor all focus code to a separate class.

The code about focus is complicated and scattered around.
Move the code to a new class, so it is easier to maintain.

Change-Id: I0214b405bf1596d967e7d89cdb04328322c6ab95

1 files changed, 423 insertions, 0 deletions

diff --git a/src/com/android/camera/FocusManager.java b/src/com/android/camera/FocusManager.java
new file mode 100644
index 0000000..390b5d9
--- /dev/null
+++ b/src/com/android/camera/FocusManager.java
@@ -0,0 +1,423 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.camera;
+
+import com.android.camera.ui.FocusRectangle;
+import com.android.camera.ui.FaceView;
+
+import android.graphics.Rect;
+import android.hardware.Camera.Area;
+import android.hardware.Camera.Parameters;
+import android.media.AudioManager;
+import android.media.ToneGenerator;
+import android.os.Handler;
+import android.os.Message;
+import android.util.Log;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.RelativeLayout;
+
+import java.util.ArrayList;
+import java.util.List;
+
+// A class that handles everything about focus in still picture mode.
+// This also handles the metering area because it is the same as focus area.
+public class FocusManager {
+    private static final String TAG = "Focus";
+
+    private static final int RESET_TOUCH_FOCUS = 0;
+    private static final int FOCUS_BEEP_VOLUME = 100;
+    private static final int RESET_TOUCH_FOCUS_DELAY = 3000;
+
+    private int mState = STATE_IDLE;
+    private static final int STATE_IDLE = 0; // Focus is not active.
+    private static final int STATE_FOCUSING = 1; // Focus is in progress.
+    // Focus is in progress and the camera should take a picture after focus finishes.
+    private static final int STATE_FOCUSING_SNAP_ON_FINISH = 2;
+    private static final int STATE_SUCCESS = 3; // Focus finishes and succeeds.
+    private static final int STATE_FAIL = 4; // Focus finishes and fails.
+
+    private boolean mInitialized;
+    private boolean mFocusAreaSupported;
+    private boolean mContinuousFocusFail;
+    private ToneGenerator mFocusToneGenerator;
+    private FocusRectangle mFocusRectangle;
+    private View mPreviewFrame;
+    private FaceView mFaceView;
+    private List<Area> mTapArea;  // focus area in driver format
+    private String mFocusMode;
+    private String mDefaultFocusMode;
+    private String mOverrideFocusMode;
+    private Parameters mParameters;
+    private ComboPreferences mPreferences;
+    private Handler mHandler;
+    Listener mListener;
+
+    public interface Listener {
+        public void autoFocus();
+        public void cancelAutoFocus();
+        public boolean capture();
+        public void startFaceDetection();
+        public void stopFaceDetection();
+        public void setFocusParameters();
+    }
+
+    private class MainHandler extends Handler {
+        @Override
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case RESET_TOUCH_FOCUS: {
+                    cancelAutoFocus();
+                    mListener.startFaceDetection();
+                    break;
+                }
+            }
+        }
+    }
+
+    public FocusManager(ComboPreferences preferences, String defaultFocusMode, Parameters parameters) {
+        mPreferences = preferences;
+        mDefaultFocusMode = defaultFocusMode;
+        mParameters = parameters;
+        mFocusAreaSupported = (mParameters.getMaxNumFocusAreas() > 0
+                && isSupported(Parameters.FOCUS_MODE_AUTO,
+                        mParameters.getSupportedFocusModes()));
+    }
+
+    public void initialize(FocusRectangle focusRectangle, View previewFrame,
+            FaceView faceView, Listener listener) {
+        mFocusRectangle = focusRectangle;
+        mPreviewFrame = previewFrame;
+        mFaceView = faceView;
+        mListener = listener;
+        mHandler = new MainHandler();
+        mInitialized = true;
+    }
+
+    public void doFocus(boolean pressed) {
+        if (!mInitialized) return;
+
+        if (!(getFocusMode().equals(Parameters.FOCUS_MODE_INFINITY)
+                || getFocusMode().equals(Parameters.FOCUS_MODE_FIXED)
+                || getFocusMode().equals(Parameters.FOCUS_MODE_EDOF))) {
+            if (pressed) {  // Focus key down.
+                // Do not focus if touch focus has been triggered.
+                if (mState != STATE_SUCCESS && mState != STATE_FAIL) {
+                    autoFocus();
+                }
+            } else {  // Focus key up.
+                // User releases half-pressed focus key.
+                if (mState == STATE_FOCUSING || mState == STATE_SUCCESS
+                        || mState == STATE_FAIL) {
+                    cancelAutoFocus();
+                }
+            }
+        }
+    }
+
+    public void doSnap() {
+        if (!mInitialized) return;
+
+        // If the user has half-pressed the shutter and focus is completed, we
+        // can take the photo right away. If the focus mode is infinity, we can
+        // also take the photo.
+        if (getFocusMode().equals(Parameters.FOCUS_MODE_INFINITY)
+                || getFocusMode().equals(Parameters.FOCUS_MODE_FIXED)
+                || getFocusMode().equals(Parameters.FOCUS_MODE_EDOF)
+                || (mState == STATE_SUCCESS
+                || mState == STATE_FAIL)) {
+            capture();
+        } else if (mState == STATE_FOCUSING) {
+            // Half pressing the shutter (i.e. the focus button event) will
+            // already have requested AF for us, so just request capture on
+            // focus here.
+            mState = STATE_FOCUSING_SNAP_ON_FINISH;
+        } else if (mState == STATE_IDLE) {
+            // Focus key down event is dropped for some reasons. Just ignore.
+        }
+    }
+
+    public void onShutter() {
+        resetTouchFocus();
+        updateFocusUI();
+        if (mFaceView != null) mFaceView.clearFaces();
+    }
+
+    public void onAutoFocus(boolean focused) {
+        // Do a full autofocus if the scene is not focused in continuous
+        // focus mode,
+        if (getFocusMode().equals(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE) && !focused) {
+            mContinuousFocusFail = true;
+            mListener.setFocusParameters();
+            autoFocus();
+            mContinuousFocusFail = false;
+        } else if (mState == STATE_FOCUSING_SNAP_ON_FINISH) {
+            // Take the picture no matter focus succeeds or fails. No need
+            // to play the AF sound if we're about to play the shutter
+            // sound.
+            if (focused) {
+                mState = STATE_SUCCESS;
+            } else {
+                mState = STATE_FAIL;
+            }
+            updateFocusUI();
+            capture();
+        } else if (mState == STATE_FOCUSING) {
+            // This happens when (1) user is half-pressing the focus key or
+            // (2) touch focus is triggered. Play the focus tone. Do not
+            // take the picture now.
+            if (focused) {
+                mState = STATE_SUCCESS;
+                if (mFocusToneGenerator != null) {
+                    mFocusToneGenerator.startTone(ToneGenerator.TONE_PROP_BEEP2);
+                }
+            } else {
+                mState = STATE_FAIL;
+            }
+            updateFocusUI();
+            // If this is triggered by touch focus, cancel focus after a
+            // while.
+            if (mTapArea != null) {
+                mHandler.sendEmptyMessageDelayed(RESET_TOUCH_FOCUS, RESET_TOUCH_FOCUS_DELAY);
+            }
+        } else if (mState == STATE_IDLE) {
+            // User has released the focus key before focus completes.
+            // Do nothing.
+        }
+    }
+
+    public boolean onTouch(MotionEvent e) {
+        if (!mInitialized || mState == STATE_FOCUSING_SNAP_ON_FINISH) return false;
+
+        // Let users be able to cancel previous touch focus.
+        if ((mTapArea != null) && (e.getAction() == MotionEvent.ACTION_DOWN)
+                && (mState == STATE_FOCUSING || mState == STATE_SUCCESS ||
+                    mState == STATE_FAIL)) {
+            cancelAutoFocus();
+        }
+
+        // Initialize variables.
+        int x = Math.round(e.getX());
+        int y = Math.round(e.getY());
+        int focusWidth = mFocusRectangle.getWidth();
+        int focusHeight = mFocusRectangle.getHeight();
+        int previewWidth = mPreviewFrame.getWidth();
+        int previewHeight = mPreviewFrame.getHeight();
+        if (mTapArea == null) {
+            mTapArea = new ArrayList<Area>();
+            mTapArea.add(new Area(new Rect(), 1));
+        }
+
+        // Convert the coordinates to driver format. The actual focus area is two times bigger than
+        // UI because a huge rectangle looks strange.
+        int areaWidth = focusWidth * 2;
+        int areaHeight = focusHeight * 2;
+        int areaLeft = Util.clamp(x - areaWidth / 2, 0, previewWidth - areaWidth);
+        int areaTop = Util.clamp(y - areaHeight / 2, 0, previewHeight - areaHeight);
+        Rect rect = mTapArea.get(0).rect;
+        convertToFocusArea(areaLeft, areaTop, areaWidth, areaHeight, previewWidth, previewHeight,
+                mTapArea.get(0).rect);
+
+        // Use margin to set the focus rectangle to the touched area.
+        RelativeLayout.LayoutParams p =
+                (RelativeLayout.LayoutParams) mFocusRectangle.getLayoutParams();
+        int left = Util.clamp(x - focusWidth / 2, 0, previewWidth - focusWidth);
+        int top = Util.clamp(y - focusHeight / 2, 0, previewHeight - focusHeight);
+        p.setMargins(left, top, 0, 0);
+        // Disable "center" rule because we no longer want to put it in the center.
+        int[] rules = p.getRules();
+        rules[RelativeLayout.CENTER_IN_PARENT] = 0;
+        mFocusRectangle.requestLayout();
+
+        // Stop face detection because we want to specify focus and metering area.
+        mListener.stopFaceDetection();
+
+        // Set the focus area and metering area.
+        mListener.setFocusParameters();
+        if (mFocusAreaSupported && (e.getAction() == MotionEvent.ACTION_UP)) {
+            autoFocus();
+        } else {  // Just show the rectangle in all other cases.
+            updateFocusUI();
+            // Reset the metering area in 3 seconds.
+            mHandler.removeMessages(RESET_TOUCH_FOCUS);
+            mHandler.sendEmptyMessageDelayed(RESET_TOUCH_FOCUS, RESET_TOUCH_FOCUS_DELAY);
+        }
+
+        return true;
+    }
+
+    public void onPreviewStarted() {
+        mState = STATE_IDLE;
+    }
+
+    public void onPreviewStopped() {
+        mState = STATE_IDLE;
+        resetTouchFocus();
+        // If auto focus was in progress, it would have been canceled.
+        updateFocusUI();
+    }
+
+    public void onCameraReleased() {
+        onPreviewStopped();
+    }
+
+    private void autoFocus() {
+        Log.v(TAG, "Start autofocus.");
+        mListener.autoFocus();
+        mState = STATE_FOCUSING;
+        // Pause the face view because the driver will keep sending face
+        // callbacks after the focus completes.
+        if (mFaceView != null) mFaceView.pause();
+        updateFocusUI();
+        mHandler.removeMessages(RESET_TOUCH_FOCUS);
+    }
+
+    private void cancelAutoFocus() {
+        Log.v(TAG, "Cancel autofocus.");
+        mListener.cancelAutoFocus();
+        if (mFaceView != null) mFaceView.resume();
+        mState = STATE_IDLE;
+        resetTouchFocus();
+        updateFocusUI();
+        mHandler.removeMessages(RESET_TOUCH_FOCUS);
+    }
+
+    private void capture() {
+        if (mListener.capture()) {
+            mState = STATE_IDLE;
+            mHandler.removeMessages(RESET_TOUCH_FOCUS);
+        }
+    }
+
+    public void initializeToneGenerator() {
+        // Initialize focus tone generator.
+        try {
+            mFocusToneGenerator = new ToneGenerator(
+                    AudioManager.STREAM_SYSTEM, FOCUS_BEEP_VOLUME);
+        } catch (Throwable ex) {
+            Log.w(TAG, "Exception caught while creating tone generator: ", ex);
+            mFocusToneGenerator = null;
+        }
+    }
+
+    public void releaseToneGenerator() {
+        if (mFocusToneGenerator != null) {
+            mFocusToneGenerator.release();
+            mFocusToneGenerator = null;
+        }
+    }
+
+    public String getFocusMode() {
+        if (mOverrideFocusMode != null) return mOverrideFocusMode;
+
+        if ((mFocusAreaSupported && mTapArea != null) || mContinuousFocusFail) {
+            // Always use autofocus in tap-to-focus or when continuous focus fails.
+            mFocusMode = Parameters.FOCUS_MODE_AUTO;
+        } else {
+            // The default is continuous autofocus.
+            mFocusMode = mPreferences.getString(
+                    CameraSettings.KEY_FOCUS_MODE, mDefaultFocusMode);
+        }
+        if (!isSupported(mFocusMode, mParameters.getSupportedFocusModes())) {
+            // For some reasons, the driver does not support the current
+            // focus mode. Fall back to auto.
+            if (isSupported(Parameters.FOCUS_MODE_AUTO,
+                    mParameters.getSupportedFocusModes())) {
+                mFocusMode = Parameters.FOCUS_MODE_AUTO;
+            } else {
+                mFocusMode = mParameters.getFocusMode();
+            }
+        }
+        return mFocusMode;
+    }
+
+    public List<Area> getTapArea() {
+        return mTapArea;
+    }
+
+    public void updateFocusUI() {
+        if (!mInitialized) return;
+
+        // Set the length of focus rectangle according to preview frame size.
+        int len = Math.min(mPreviewFrame.getWidth(), mPreviewFrame.getHeight()) / 4;
+        ViewGroup.LayoutParams layout = mFocusRectangle.getLayoutParams();
+        layout.width = len;
+        layout.height = len;
+
+        if (mState == STATE_IDLE) {
+            if (mTapArea == null) {
+                mFocusRectangle.clear();
+            } else {
+                // Users touch on the preview and the rectangle indicates the
+                // metering area. Either focus area is not supported or
+                // autoFocus call is not required.
+                mFocusRectangle.showStart();
+            }
+            return;
+        }
+
+        // Do not show focus rectangle if there is any face rectangle.
+        if (mFaceView != null && mFaceView.faceExists()) return;
+
+        if (mState == STATE_FOCUSING || mState == STATE_FOCUSING_SNAP_ON_FINISH) {
+            mFocusRectangle.showStart();
+        } else if (mState == STATE_SUCCESS) {
+            mFocusRectangle.showSuccess();
+        } else if (mState == STATE_FAIL) {
+            mFocusRectangle.showFail();
+        }
+    }
+
+    public void resetTouchFocus() {
+        if (!mInitialized) return;
+
+        // Put focus rectangle to the center.
+        RelativeLayout.LayoutParams p =
+                (RelativeLayout.LayoutParams) mFocusRectangle.getLayoutParams();
+        int[] rules = p.getRules();
+        rules[RelativeLayout.CENTER_IN_PARENT] = RelativeLayout.TRUE;
+        p.setMargins(0, 0, 0, 0);
+
+        mTapArea = null;
+    }
+
+    // Convert the touch point to the focus area in driver format.
+    public static void convertToFocusArea(int left, int top, int focusWidth, int focusHeight,
+            int previewWidth, int previewHeight, Rect rect) {
+        rect.left = Math.round((float) left / previewWidth * 2000 - 1000);
+        rect.top = Math.round((float) top / previewHeight * 2000 - 1000);
+        rect.right = Math.round((float) (left + focusWidth) / previewWidth * 2000 - 1000);
+        rect.bottom = Math.round((float) (top + focusHeight) / previewHeight * 2000 - 1000);
+    }
+
+    public boolean isFocusCompleted() {
+        return mState == STATE_SUCCESS || mState == STATE_FAIL;
+    }
+
+    public void removeMessages() {
+        mHandler.removeMessages(RESET_TOUCH_FOCUS);
+    }
+
+    public void overrideFocusMode(String focusMode) {
+        mOverrideFocusMode = focusMode;
+    }
+
+    private static boolean isSupported(String value, List<String> supported) {
+        return supported == null ? false : supported.indexOf(value) >= 0;
+    }
+}