/*
* Copyright (C) 2008 ZXing authors
*
* 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.barcode.camera;
import java.io.IOException;
import com.google.zxing.PlanarYUVLuminanceSource;
import android.content.Context;
import android.graphics.Point;
import android.graphics.Rect;
import android.hardware.Camera;
import android.os.Handler;
import android.util.Log;
import android.view.SurfaceHolder;
/**
* 相机管理类
*
*/
public final class CameraManager {
private static final String TAG = CameraManager.class.getSimpleName();
private static final int MIN_FRAME_WIDTH = 350;
private static final int MAX_FRAME_WIDTH = 420;
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 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 = new OpenCameraManager().build().open();
if (theCamera == null) {
throw new IOException();
}
camera = theCamera;
}
theCamera.setPreviewDisplay(holder);
if (!initialized) {
initialized = true;
configManager.initFromCameraParameters(theCamera);
if (requestedFramingRectWidth > 0 && requestedFramingRectHeight > 0) {
setManualFramingRect(requestedFramingRectWidth,
requestedFramingRectHeight);
requestedFramingRectWidth = 0;
requestedFramingRectHeight = 0;
}
}
Camera.Parameters parameters = theCamera.getParameters();
String parametersFlattened = parameters == null ? null : parameters
.flatten(); // Save these, temporarily
try {
configManager.setDesiredCameraParameters(theCamera, false);
} catch (RuntimeException re) {
// Driver failed
Log.w(TAG,
"Camera rejected parameters. Setting only minimal safe-mode parameters");
Log.i(TAG, "Resetting to saved camera params: "
+ parametersFlattened);
// Reset:
if (parametersFlattened != null) {
parameters = theCamera.getParameters();
parameters.unflatten(parametersFlattened);
try {
theCamera.setParameters(parameters);
configManager.setDesiredCameraParameters(theCamera, true);
} catch (RuntimeException re2) {
// Well, darn. Give up
Log.w(TAG,
"Camera rejected even safe-mode parameters! No configuration");
}
}
}
}
public synchronized boolean isOpen() {
return camera != null;
}
/**
* 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;
}
}
/**
* Convenience method for {@link com.barcode.core.Capture}
*/
public synchronized void setTorch(boolean newSetting) {
if (camera != null) {
if (autoFocusManager != null) {
autoFocusManager.stop();
}
configManager.setTorch(camera, newSetting);
if (autoFocusManager != null) {
autoFocusManager.start();
}
}
}
/**
* 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 requestPreviewFrame(Handler handler, int message) {
Camera theCamera = camera;
if (theCamera != null && previewing) {
previewCallback.setHandler(handler, message);
theCamera.setOneShotPreviewCallback(previewCallback);
}
}
/**
* 动态获得扫描框的大小 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;
}
// 计算扫描框的宽高
int width = screenResolution.x * 3 / 4;
if (width < MIN_FRAME_WIDTH) {
width = MIN_FRAME_WIDTH;
} else if (width > MAX_FRAME_WIDTH) {
width = MAX_FRAME_WIDTH;
}
int height = width;
int leftOffset = (screenResolution.x - width) / 2;
int topOffset = (screenResolution.y - width) / 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 framingRect = getFramingRect();
if (framingRect == null) {
return null;
}
Rect rect = new Rect(framingRect);
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.y / screenResolution.x;
rect.right = rect.right * cameraResolution.y / screenResolution.x;
rect.top = rect.top * cameraResolution.x / screenResolution.y;
rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;
framingRectInPreview = rect;
}
return framingRectInPreview;
}
/**
* Allows third party apps to specify the scanning rectangle dimensions,
* rather than determine them automatically based on screen resolution.
*
* @param width
* The width in pixels to scan.
* @param height
* The height in pixels to scan.
*/
public synchronized void setManualFramingRect(int width, int height) {
if (initialized) {
Point screenResolution = configManager.getScreenResolution();
if (width > screenResolution.x) {
width = screenResolution.x;
}
if (height > screenResolution.y) {
height = screenResolution.y;
}
int leftOffset = (screenResolution.x - width) / 2;
int topOffset = (screenResolution.y - height) / 2;
framingRect = new Rect(leftOffset, topOffset, leftOffset + width,
topOffset + height);
Log.d(TAG, "Calculated manual framing rect: " + framingRect);
framingRectInPreview = null;
} else {
requestedFramingRectWidth = width;
requestedFramingRectHeight = height;
}
}
/**
* 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(), false);
}
}