/*
* Copyright (C) 2008 ZXing authors
* Copyright 2011 Robert Theis
*
* 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 edu.sfsu.cs.orange.ocr.camera;
import java.io.IOException;
import android.content.Context;
import android.content.SharedPreferences;
import android.graphics.Point;
import android.graphics.Rect;
import android.hardware.Camera;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.view.SurfaceHolder;
import edu.sfsu.cs.orange.ocr.PlanarYUVLuminanceSource;
import edu.sfsu.cs.orange.ocr.PreferencesActivity;
/**
* This object wraps the Camera service object and expects to be the only one talking to it. The
* implementation encapsulates the steps needed to take preview-sized images, which are used for
* both preview and decoding.
*
* The code for this class was adapted from the ZXing project: http://code.google.com/p/zxing
*/
public final class CameraManager {
private static final String TAG = CameraManager.class.getSimpleName();
private static final int MIN_FRAME_WIDTH = 50; // originally 240
private static final int MIN_FRAME_HEIGHT = 20; // originally 240
private static final int MAX_FRAME_WIDTH = 800; // originally 480
private static final int MAX_FRAME_HEIGHT = 600; // originally 360
private final Context context;
private final CameraConfigurationManager configManager;
private Camera camera;
private AutoFocusManager autoFocusManager;
private Rect framingRect;
private Rect framingRectInPreview;
private boolean initialized;
private boolean previewing;
private boolean reverseImage;
private int requestedFramingRectWidth;
private int requestedFramingRectHeight;
/**
* Preview frames are delivered here, which we pass on to the registered handler. Make sure to
* clear the handler so it will only receive one message.
*/
private final PreviewCallback previewCallback;
public CameraManager(Context context) {
this.context = context;
this.configManager = new CameraConfigurationManager(context);
previewCallback = new PreviewCallback(configManager);
}
/**
* Opens the camera driver and initializes the hardware parameters.
*
* @param holder The surface object which the camera will draw preview frames into.
* @throws IOException Indicates the camera driver failed to open.
*/
public synchronized void openDriver(SurfaceHolder holder) throws IOException {
Camera theCamera = camera;
if (theCamera == null) {
theCamera = Camera.open();
if (theCamera == null) {
throw new IOException();
}
camera = theCamera;
}
camera.setPreviewDisplay(holder);
if (!initialized) {
initialized = true;
configManager.initFromCameraParameters(theCamera);
if (requestedFramingRectWidth > 0 && requestedFramingRectHeight > 0) {
adjustFramingRect(requestedFramingRectWidth, requestedFramingRectHeight);
requestedFramingRectWidth = 0;
requestedFramingRectHeight = 0;
}
}
configManager.setDesiredCameraParameters(theCamera);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
reverseImage = prefs.getBoolean(PreferencesActivity.KEY_REVERSE_IMAGE, false);
}
/**
* Closes the camera driver if still in use.
*/
public synchronized void closeDriver() {
if (camera != null) {
camera.release();
camera = null;
// Make sure to clear these each time we close the camera, so that any scanning rect
// requested by intent is forgotten.
framingRect = null;
framingRectInPreview = null;
}
}
/**
* Asks the camera hardware to begin drawing preview frames to the screen.
*/
public synchronized void startPreview() {
Camera theCamera = camera;
if (theCamera != null && !previewing) {
theCamera.startPreview();
previewing = true;
autoFocusManager = new AutoFocusManager(context, camera);
}
}
/**
* Tells the camera to stop drawing preview frames.
*/
public synchronized void stopPreview() {
if (autoFocusManager != null) {
autoFocusManager.stop();
autoFocusManager = null;
}
if (camera != null && previewing) {
camera.stopPreview();
previewCallback.setHandler(null, 0);
previewing = false;
}
}
/**
* A single preview frame will be returned to the handler supplied. The data will arrive as byte[]
* in the message.obj field, with width and height encoded as message.arg1 and message.arg2,
* respectively.
*
* @param handler The handler to send the message to.
* @param message The what field of the message to be sent.
*/
public synchronized void requestOcrDecode(Handler handler, int message) {
Camera theCamera = camera;
if (theCamera != null && previewing) {
previewCallback.setHandler(handler, message);
theCamera.setOneShotPreviewCallback(previewCallback);
}
}
/**
* Asks the camera hardware to perform an autofocus.
* @param delay Time delay to send with the request
*/
public synchronized void requestAutoFocus(long delay) {
autoFocusManager.start(delay);
}
/**
* Calculates the framing rect which the UI should draw to show the user where to place the
* barcode. This target helps with alignment as well as forces the user to hold the device
* far enough away to ensure the image will be in focus.
*
* @return The rectangle to draw on screen in window coordinates.
*/
public synchronized Rect getFramingRect() {
if (framingRect == null) {
if (camera == null) {
return null;
}
Point screenResolution = configManager.getScreenResolution();
if (screenResolution == null) {
// Called early, before init even finished
return null;
}
int width = screenResolution.x * 3/5;
if (width < MIN_FRAME_WIDTH) {
width = MIN_FRAME_WIDTH;
} else if (width > MAX_FRAME_WIDTH) {
width = MAX_FRAME_WIDTH;
}
int height = screenResolution.y * 1/5;
if (height < MIN_FRAME_HEIGHT) {
height = MIN_FRAME_HEIGHT;
} else if (height > MAX_FRAME_HEIGHT) {
height = MAX_FRAME_HEIGHT;
}
int leftOffset = (screenResolution.x - width) / 2;
int topOffset = (screenResolution.y - height) / 2;
framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height);
}
return framingRect;
}
/**
* Like {@link #getFramingRect} but coordinates are in terms of the preview frame,
* not UI / screen.
*/
public synchronized Rect getFramingRectInPreview() {
if (framingRectInPreview == null) {
Rect rect = new Rect(getFramingRect());
Point cameraResolution = configManager.getCameraResolution();
Point screenResolution = configManager.getScreenResolution();
if (cameraResolution == null || screenResolution == null) {
// Called early, before init even finished
return null;
}
rect.left = rect.left * cameraResolution.x / screenResolution.x;
rect.right = rect.right * cameraResolution.x / screenResolution.x;
rect.top = rect.top * cameraResolution.y / screenResolution.y;
rect.bottom = rect.bottom * cameraResolution.y / screenResolution.y;
framingRectInPreview = rect;
}
return framingRectInPreview;
}
/**
* Changes the size of the framing rect.
*
* @param deltaWidth Number of pixels to adjust the width
* @param deltaHeight Number of pixels to adjust the height
*/
public synchronized void adjustFramingRect(int deltaWidth, int deltaHeight) {
if (initialized) {
Point screenResolution = configManager.getScreenResolution();
// Set maximum and minimum sizes
if ((framingRect.width() + deltaWidth > screenResolution.x - 4) || (framingRect.width() + deltaWidth < 50)) {
deltaWidth = 0;
}
if ((framingRect.height() + deltaHeight > screenResolution.y - 4) || (framingRect.height() + deltaHeight < 50)) {
deltaHeight = 0;
}
int newWidth = framingRect.width() + deltaWidth;
int newHeight = framingRect.height() + deltaHeight;
int leftOffset = (screenResolution.x - newWidth) / 2;
int topOffset = (screenResolution.y - newHeight) / 2;
framingRect = new Rect(leftOffset, topOffset, leftOffset + newWidth, topOffset + newHeight);
framingRectInPreview = null;
} else {
requestedFramingRectWidth = deltaWidth;
requestedFramingRectHeight = deltaHeight;
}
}
/**
* A factory method to build the appropriate LuminanceSource object based on the format
* of the preview buffers, as described by Camera.Parameters.
*
* @param data A preview frame.
* @param width The width of the image.
* @param height The height of the image.
* @return A PlanarYUVLuminanceSource instance.
*/
public PlanarYUVLuminanceSource buildLuminanceSource(byte[] data, int width, int height) {
Rect rect = getFramingRectInPreview();
if (rect == null) {
return null;
}
// Go ahead and assume it's YUV rather than die.
return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
rect.width(), rect.height(), reverseImage);
}
}