Add support for manual tap to focus

library/src/main/api14/com/google/android/cameraview/Camera1.java

@@ -17,13 +17,17 @@
 package com.google.android.cameraview;
 
 import android.annotation.SuppressLint;
+import android.graphics.Rect;
+import android.graphics.RectF;
 import android.graphics.SurfaceTexture;
 import android.hardware.Camera;
 import android.os.Build;
+import android.os.Handler;
 import android.support.v4.util.SparseArrayCompat;
 import android.view.SurfaceHolder;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.SortedSet;
@@ -49,6 +53,8 @@ class Camera1 extends CameraViewImpl {
 
     private final AtomicBoolean isPictureCaptureInProgress = new AtomicBoolean(false);
 
+    private final AtomicBoolean isAutoFocusInProgress = new AtomicBoolean(false);
+
     Camera mCamera;
 
     private Camera.Parameters mCameraParameters;
@@ -71,11 +77,30 @@ class Camera1 extends CameraViewImpl {
 
     private int mDisplayOrientation;
 
+    private CameraCoordinateTransformer mCoordinateTransformer;
+
+    private Rect mPreviewRect = new Rect(0, 0, 0, 0);
+
+    private final Handler mCameraHandler;
+
+    private final Runnable mReturnToContinuousAFRunnable = new Runnable() {
+        @Override
+        public void run() {
+            if (setAutoFocusInternal(mAutoFocus)) {
+                mCamera.setParameters(mCameraParameters);
+                mCamera.cancelAutoFocus();
+            }
+        }
+    };
+
     Camera1(Callback callback, PreviewImpl preview) {
         super(callback, preview);
+        mCameraHandler = new Handler();
         preview.setCallback(new PreviewImpl.Callback() {
             @Override
             public void onSurfaceChanged() {
+                mPreviewRect.set(0, 0, mPreview.getWidth(), mPreview.getHeight());
+                resetCoordinateTransformer();
                 if (mCamera != null) {
                     setUpPreview();
                     adjustCameraParameters();
@@ -103,6 +128,7 @@ void stop() {
         }
         mShowingPreview = false;
         releaseCamera();
+        mCameraHandler.removeCallbacks(mReturnToContinuousAFRunnable);
     }
 
     // Suppresses Camera#setPreviewTexture
@@ -141,6 +167,7 @@ void setFacing(int facing) {
             stop();
             start();
         }
+        resetCoordinateTransformer();
     }
 
     @Override
@@ -223,11 +250,12 @@ void takePicture() {
             throw new IllegalStateException(
                     "Camera is not ready. Call start() before takePicture().");
         }
-        if (getAutoFocus()) {
+        if (getAutoFocus() || isAutoFocusInProgress.get()) {
             mCamera.cancelAutoFocus();
             mCamera.autoFocus(new Camera.AutoFocusCallback() {
                 @Override
                 public void onAutoFocus(boolean success, Camera camera) {
+                    isAutoFocusInProgress.set(false);
                     takePictureInternal();
                 }
             });
@@ -238,7 +266,14 @@ public void onAutoFocus(boolean success, Camera camera) {
 
     void takePictureInternal() {
         if (!isPictureCaptureInProgress.getAndSet(true)) {
-            mCamera.takePicture(null, null, null, new Camera.PictureCallback() {
+            mCamera.takePicture(new Camera.ShutterCallback() {
+                @Override
+                public void onShutter() {
+                    if (setAutoFocusInternal(mAutoFocus)) {
+                        mCamera.setParameters(mCameraParameters);
+                    }
+                }
+            }, null, null, new Camera.PictureCallback() {
                 @Override
                 public void onPictureTaken(byte[] data, Camera camera) {
                     isPictureCaptureInProgress.set(false);
@@ -247,6 +282,7 @@ public void onPictureTaken(byte[] data, Camera camera) {
                     camera.startPreview();
                 }
             });
+            mCameraHandler.removeCallbacks(mReturnToContinuousAFRunnable);
         }
     }
 
@@ -256,6 +292,7 @@ void setDisplayOrientation(int displayOrientation) {
             return;
         }
         mDisplayOrientation = displayOrientation;
+        resetCoordinateTransformer();
         if (isCameraOpened()) {
             int cameraRotation = calcCameraRotation(displayOrientation);
             mCameraParameters.setRotation(cameraRotation);
@@ -271,6 +308,49 @@ void setDisplayOrientation(int displayOrientation) {
         }
     }
 
+    @Override
+    boolean hasManualFocus() {
+        return isCameraOpened() && getFacing() == Constants.FACING_BACK
+                && (isFocusAreaSupported() || isMeteringAreaSupported());
+    }
+
+    @Override
+    void setFocusAt(int x, int y) {
+        if (isPictureCaptureInProgress.get()) {
+            return;
+        }
+        mCallback.onFocusAt(x, y);
+        if (isAutoFocusInProgress.getAndSet(false)) {
+            mCamera.cancelAutoFocus();
+        }
+        if (!isAutoFocusInProgress.getAndSet(true) && setFocusAndMeterInternal(x, y)) {
+            mCamera.setParameters(mCameraParameters);
+            mCamera.autoFocus(new Camera.AutoFocusCallback() {
+                @Override
+                public void onAutoFocus(boolean success, Camera camera) {
+                    isAutoFocusInProgress.set(false);
+                    resumeContinuousAFAfterDelay(Constants.FOCUS_HOLD_MILLIS);
+                }
+            });
+        }
+    }
+
+    boolean isFocusAreaSupported() {
+        if (Build.VERSION.SDK_INT >= 14) {
+            List<String> supportedFocusModes = mCameraParameters.getSupportedFocusModes();
+            return (supportedFocusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)
+                    && mCameraParameters.getMaxNumFocusAreas() > 0);
+        }
+        return false;
+    }
+
+    boolean isMeteringAreaSupported() {
+        if (Build.VERSION.SDK_INT >= 14) {
+            return mCameraParameters.getMaxNumMeteringAreas() > 0;
+        }
+        return false;
+    }
+
     /**
      * This rewrites {@link #mCameraId} and {@link #mCameraInfo}.
      */
@@ -406,6 +486,10 @@ private boolean setAutoFocusInternal(boolean autoFocus) {
             } else {
                 mCameraParameters.setFocusMode(modes.get(0));
             }
+            if (Build.VERSION.SDK_INT >= 14) {
+                mCameraParameters.setFocusAreas(null);
+                mCameraParameters.setMeteringAreas(null);
+            }
             return true;
         } else {
             return false;
@@ -437,4 +521,69 @@ private boolean setFlashInternal(int flash) {
         }
     }
 
+    /**
+     * @return {@code true} if {@link #mCameraParameters} was modified.
+     */
+    private boolean setFocusAndMeterInternal(int x, int y) {
+        if (Build.VERSION.SDK_INT >= 14 && hasManualFocus() && mCoordinateTransformer != null) {
+            if (isFocusAreaSupported()) {
+                List<Camera.Area> focusArea = Collections.singletonList(
+                        new Camera.Area(computeCameraRectFromPreviewCoordinates(x, y,
+                                getAFRegionSizePx()), 1));
+                mCameraParameters.setFocusAreas(focusArea);
+            }
+            if (isMeteringAreaSupported()) {
+                List<Camera.Area> meteringArea = Collections.singletonList(
+                        new Camera.Area(computeCameraRectFromPreviewCoordinates(x, y,
+                                getAERegionSizePx()), 1));
+                mCameraParameters.setMeteringAreas(meteringArea);
+            }
+            mCameraParameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * @return {@code width} of auto focus region in pixels.
+     */
+    private int getAFRegionSizePx() {
+        return (int) (Math.min(mPreview.getWidth(), mPreview.getHeight())
+                * Constants.AF_REGION_BOX);
+    }
+
+    /**
+     * @return {@code width} of metering region in pixels.
+     */
+    private int getAERegionSizePx() {
+        return (int) (Math.min(mPreview.getWidth(), mPreview.getHeight())
+                * Constants.AE_REGION_BOX);
+    }
+
+    private Rect computeCameraRectFromPreviewCoordinates(int x, int y, int size) {
+        int left = CameraUtil.clamp(x - size / 2, mPreviewRect.left,
+                mPreviewRect.right - size);
+        int top = CameraUtil.clamp(y - size / 2, mPreviewRect.top,
+                mPreviewRect.bottom - size);
+        RectF rectF = new RectF(left, top, left + size, top + size);
+        return CameraUtil.rectFToRect(mCoordinateTransformer.toCameraSpace(rectF));
+    }
+
+    private void resetCoordinateTransformer() {
+        if (mPreview.getWidth() > 0 && mPreview.getHeight() > 0) {
+            mCoordinateTransformer = new CameraCoordinateTransformer(
+                    mFacing == Constants.FACING_FRONT,
+                    calcCameraRotation(mDisplayOrientation),
+                    CameraUtil.rectToRectF(mPreviewRect));
+        }
+    }
+
+    /**
+     * Resume AF_MODE_CONTINUOUS_PICTURE after FOCUS_HOLD_MILLIS.
+     */
+    private void resumeContinuousAFAfterDelay(int millis) {
+        mCameraHandler.removeCallbacks(mReturnToContinuousAFRunnable);
+        mCameraHandler.postDelayed(mReturnToContinuousAFRunnable, millis);
+    }
 }

library/src/main/api14/com/google/android/cameraview/CameraCoordinateTransformer.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2016 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.google.android.cameraview;
+
+import android.graphics.Matrix;
+import android.graphics.RectF;
+
+/**
+ * Transform coordinates to and from preview coordinate space and camera driver
+ * coordinate space.
+ */
+public class CameraCoordinateTransformer {
+
+    // http://developer.android.com/guide/topics/media/camera.html#metering-focus-areas
+    private static final RectF CAMERA_DRIVER_RECT = new RectF(-1000, -1000, 1000, 1000);
+    private final Matrix mCameraToPreviewTransform;
+    private final Matrix mPreviewToCameraTransform;
+
+    /**
+     * Convert rectangles to / from camera coordinate and preview coordinate space.
+     *
+     * @param mirrorX            if the preview is mirrored along the X axis.
+     * @param displayOrientation orientation in degrees.
+     * @param previewRect        the preview rectangle size and position.
+     */
+    public CameraCoordinateTransformer(boolean mirrorX, int displayOrientation,
+            RectF previewRect) {
+        if (!hasNonZeroArea(previewRect)) {
+            throw new IllegalArgumentException("previewRect");
+        }
+        mCameraToPreviewTransform = cameraToPreviewTransform(mirrorX, displayOrientation,
+                previewRect);
+        mPreviewToCameraTransform = inverse(mCameraToPreviewTransform);
+    }
+
+    /**
+     * Transform a rectangle in camera space into a new rectangle in preview
+     * view space.
+     *
+     * @param source the rectangle in camera space
+     * @return the rectangle in preview view space.
+     */
+    public RectF toPreviewSpace(RectF source) {
+        RectF result = new RectF();
+        mCameraToPreviewTransform.mapRect(result, source);
+        return result;
+    }
+
+    /**
+     * Transform a rectangle in preview view space into a new rectangle in
+     * camera view space.
+     *
+     * @param source the rectangle in preview view space
+     * @return the rectangle in camera view space.
+     */
+    public RectF toCameraSpace(RectF source) {
+        RectF result = new RectF();
+        mPreviewToCameraTransform.mapRect(result, source);
+        return result;
+    }
+
+    private Matrix cameraToPreviewTransform(boolean mirrorX, int displayOrientation,
+            RectF previewRect) {
+        Matrix transform = new Matrix();
+        // Need mirror for front camera.
+        transform.setScale(mirrorX ? -1 : 1, 1);
+        // Apply a rotate transform.
+        // This is the value for android.hardware.Camera.setDisplayOrientation.
+        transform.postRotate(displayOrientation);
+        // Map camera driver coordinates to preview rect coordinates
+        Matrix fill = new Matrix();
+        fill.setRectToRect(CAMERA_DRIVER_RECT,
+                previewRect,
+                Matrix.ScaleToFit.FILL);
+        // Concat the previous transform on top of the fill behavior.
+        transform.setConcat(fill, transform);
+        return transform;
+    }
+
+    private Matrix inverse(Matrix source) {
+        Matrix newMatrix = new Matrix();
+        source.invert(newMatrix);
+        return newMatrix;
+    }
+
+    private boolean hasNonZeroArea(RectF rect) {
+        return rect.width() != 0 && rect.height() != 0;
+    }
+}