打印手机摄像头的支持参数+将预览帧转换为位图+获取最佳预览
【摘要】
打印手机摄像头的支持参数+将预览帧转换为位图
public class SecondActivity extends Activity implements SurfaceHolder.Callback, PreviewCallback{ // 定义对象 private SurfaceView mSurfaceview = null...
打印手机摄像头的支持参数+将预览帧转换为位图
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public class SecondActivity extends Activity implements SurfaceHolder.Callback,
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PreviewCallback
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{
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// 定义对象
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private SurfaceView mSurfaceview = null; // SurfaceView对象：(视图组件)视频显示
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private SurfaceHolder mSurfaceHolder = null; // SurfaceHolder对象：(抽象接口)SurfaceView支持类
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private Camera mCamera = null; // Camera对象，相机预览
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private String TAG = "SnapCamera";
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private boolean bIfPreview = false;
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private int mPreviewWidth;
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private int mPreviewHeight;
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Bitmap mBitmap = null;
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@Override
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protected void onCreate(Bundle savedInstanceState)
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{
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// TODO Auto-generated method stub
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super.onCreate(savedInstanceState);
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setContentView(R.layout.activity_main);
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initSurfaceView();
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}
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// InitSurfaceView
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private void initSurfaceView()
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{
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mSurfaceview = (SurfaceView) this.findViewById(R.id.CameraView);
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mSurfaceHolder = mSurfaceview.getHolder(); // 绑定SurfaceView，取得SurfaceHolder对象
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mSurfaceHolder.addCallback(SecondActivity.this); // SurfaceHolder加入回调接口
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// mSurfaceHolder.setFixedSize(176, 144); // 预览大小設置
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mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);// 设置显示器类型，setType必须设置
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}
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/* 【2】【相机预览】 */
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private void initCamera()// surfaceChanged中调用
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{
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Log.i(TAG, "going into initCamera");
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if (bIfPreview)
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{
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mCamera.stopPreview();// stopCamera();
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}
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if (null != mCamera)
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{
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try
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{
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/* Camera Service settings */
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Camera.Parameters parameters = mCamera.getParameters();
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// parameters.setFlashMode("off"); // 无闪光灯
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parameters.setPictureFormat(PixelFormat.JPEG); // Sets the image format for picture 设定相片格式为JPEG，默认为NV21
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parameters.setPreviewFormat(PixelFormat.YCbCr_420_SP); // Sets the image format for preview picture，默认为NV21
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/*
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* 【ImageFormat】JPEG/NV16(YCrCb format，used for
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* Video)/NV21(YCrCb format，used for Image)/RGB_565/YUY2/YU12
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*/
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// 【调试】获取camera支持的PictrueSize，看看能否设置
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List<Size> pictureSizes = mCamera.getParameters()
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.getSupportedPictureSizes();
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List<Size> previewSizes = mCamera.getParameters()
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.getSupportedPreviewSizes();
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List<Integer> previewFormats = mCamera.getParameters()
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.getSupportedPreviewFormats();
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List<Integer> previewFrameRates = mCamera.getParameters()
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.getSupportedPreviewFrameRates();
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Log.i(TAG + "initCamera", " support parameters is ");
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Size psize = null;
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for (int i = 0; i < pictureSizes.size(); i++)
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{
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psize = pictureSizes.get(i);
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Log.i(TAG + "initCamera", "PictrueSize,width: "
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+ psize.width + " height:" + psize.height);
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}
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for (int i = 0; i < previewSizes.size(); i++)
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{
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psize = previewSizes.get(i);
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Log.i(TAG + "initCamera", "PreviewSize,width: "
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+ psize.width + " height:" + psize.height);
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}
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Integer pf = null;
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for (int i = 0; i < previewFormats.size(); i++)
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{
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pf = previewFormats.get(i);
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Log.i(TAG + "initCamera", "PreviewFormats:" + pf);
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}
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Iterator<Integer> it = previewFrameRates.iterator();
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while (it.hasNext())
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{
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Log.i(TAG + "initCamera", "PreviewFrameRates:" + it.next());
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}
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// 设置拍照和预览图片大小
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parameters.setPictureSize(640, 480); // 指定拍照图片的大小
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parameters.setPreviewSize(mPreviewWidth, mPreviewHeight); // 指定preview的大小
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// 这两个属性 如果这两个属性设置的和真实手机的不一样时，就会报错
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// 横竖屏镜头自动调整
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if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE)
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{
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parameters.set("orientation", "portrait"); //
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parameters.set("rotation", 90); // 镜头角度转90度（默认摄像头是横拍）
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mCamera.setDisplayOrientation(90); // 在2.2以上可以使用
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} else
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// 如果是横屏
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{
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parameters.set("orientation", "landscape"); //
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mCamera.setDisplayOrientation(0); // 在2.2以上可以使用
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}
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/* 视频流编码处理 */
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// 添加对视频流处理函数
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// 设定配置参数并开启预览
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mCamera.setParameters(parameters); // 将Camera.Parameters设定予Camera
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mCamera.startPreview(); // 打开预览画面
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bIfPreview = true;
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// 【调试】设置后的图片大小和预览大小以及帧率
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Camera.Size csize = mCamera.getParameters().getPreviewSize();
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mPreviewHeight = csize.height;
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mPreviewWidth = csize.width;
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Log.i(TAG + "initCamera", "After setting, PreviewSize:width: "
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+ csize.width + " height: " + csize.height);
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csize = mCamera.getParameters().getPictureSize();
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Log.i(TAG + "initCamera", "After setting, PictrueSize:width: "
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+ csize.width + " height: " + csize.height);
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Log.i(TAG + "initCamera", "After setting, PreviewFormat is "
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+ mCamera.getParameters().getPreviewFormat());
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Log.i(TAG + "initCamera", "After setting, PreviewFrameRate is "
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+ mCamera.getParameters().getPreviewFrameRate());
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} catch (Exception e)
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{
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e.printStackTrace();
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}
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}
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}
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/* 【SurfaceHolder.Callback 回调函数】 */
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public void surfaceCreated(SurfaceHolder holder)
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// SurfaceView启动时/初次实例化，预览界面被创建时，该方法被调用。
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{
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// TODO Auto-generated method stub
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mCamera = Camera.open();// 开启摄像头（2.3版本后支持多摄像头,需传入参数）
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try
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{
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Log.i(TAG, "SurfaceHolder.Callback：surface Created");
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mCamera.setPreviewDisplay(mSurfaceHolder);// set the surface to be
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// used for live preview
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mCamera.setPreviewCallback(SecondActivity.this);
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} catch (Exception ex)
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{
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if (null != mCamera)
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{
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mCamera.release();
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mCamera = null;
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}
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Log.i(TAG + "initCamera", ex.getMessage());
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}
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}
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public void surfaceChanged(SurfaceHolder holder, int format, int width,
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int height)
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// 当SurfaceView/预览界面的格式和大小发生改变时，该方法被调用
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{
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// TODO Auto-generated method stub
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Log.i(TAG, "SurfaceHolder.Callback: Surface Changed");
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mPreviewHeight = height;
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mPreviewWidth = width;
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initCamera();
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}
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public void surfaceDestroyed(SurfaceHolder holder)
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// SurfaceView销毁时，该方法被调用
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{
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// TODO Auto-generated method stub
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Log.i(TAG, "SurfaceHolder.Callback：Surface Destroyed");
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if (null != mCamera)
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{
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mCamera.setPreviewCallback(null); // ！！这个必须在前，不然退出出错
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mCamera.stopPreview();
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bIfPreview = false;
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mCamera.release();
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mCamera = null;
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}
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}
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@Override
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public void onPreviewFrame(byte[] data, Camera camera)
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{
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// TODO Auto-generated method stub
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Camera.Parameters parameters = camera.getParameters();
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int format = parameters.getPreviewFormat();
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if (mBitmap != null)
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{
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mBitmap.recycle();
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mBitmap = null;
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}
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// YUV formats require more conversion
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if (format == PixelFormat.YCbCr_420_SP
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|| format == PixelFormat.YCbCr_422_I)
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{
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int w = 100/* parameters.getPreviewSize().width */;
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int h = 100/* parameters.getPreviewSize().height */;
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// Get the YuV image 由于此方法适用于android 2.2版本，所以此处不能用。
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// YuvImage yuv_image = new YuvImage(data, format, w, h, null);
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// // Convert YuV to Jpeg
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// Rect rect = new Rect(0, 0, w, h);
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// ByteArrayOutputStream output_stream = new
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// ByteArrayOutputStream();
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// yuv_image.compressToJpeg(rect, 100, output_stream);
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// // Convert from Jpeg to Bitmap
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// bitmap2 = BitmapFactory.decodeByteArray(output_stream
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// .toByteArray(), 0, output_stream.size());
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int[] i = new int[data.length];
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decodeYUV420SP(i, data, w, h);
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mBitmap = Bitmap.createBitmap(i, w, h, Bitmap.Config.RGB_565);
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// mBitmap = renderCroppedGreyscaleBitmap(data, w, h);
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// Log.e(TAG, "Image format is YUV:" + format);
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}
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// Jpeg and RGB565 are supported by BitmapFactory.decodeByteArray
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else if (format == PixelFormat.JPEG || format == PixelFormat.RGB_565)
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{
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// Log.e(TAG, "Image format is JPEG/RGB:" + format);
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mBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
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}
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}
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private void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width,
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int height)
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{
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// TODO Auto-generated method stub
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final int frameSize = width * height;
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for (int j = 0, yp = 0; j < height; j++)
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{
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int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
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for (int i = 0; i < width; i++, yp++)
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{
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int y = (0xff & ((int) yuv420sp[yp])) - 16;
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if (y < 0)
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y = 0;
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if ((i & 1) == 0)
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{
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v = (0xff & yuv420sp[uvp++]) - 128;
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u = (0xff & yuv420sp[uvp++]) - 128;
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}
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int y1192 = 1192 * y;
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int r = (y1192 + 1634 * v);
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int g = (y1192 - 833 * v - 400 * u);
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int b = (y1192 + 2066 * u);
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if (r < 0)
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r = 0;
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else if (r > 262143)
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r = 262143;
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if (g < 0)
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g = 0;
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else if (g > 262143)
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g = 262143;
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if (b < 0)
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b = 0;
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else if (b > 262143)
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b = 262143;
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rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000)
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| ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
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}
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}
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}
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}
在给定最大范围的条件下获取最佳预览的方法：
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private void getBestPreviewSize(Camera camera, Parameters parameters, SurfaceView cameraView)
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{
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int bestWidth=0;
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int bestHeight=0;
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List<Size> previewSizes=parameters.getSupportedPreviewSizes();
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if(previewSizes.size()>1)
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{
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Iterator<Size> cei=previewSizes.iterator();
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while(cei.hasNext())
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{
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Size aSize=cei.next();
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Log.v("snap shot","Checking "+aSize.width+"*"+aSize.height);
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if(aSize.width>bestWidth && aSize.width<=LARGETST_WIDTH
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&& aSize.height >bestHeight
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&& aSize.height<=LARGETST_HEIGHT)
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{
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bestWidth=aSize.width;
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bestHeight=aSize.height;
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}
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}
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if(bestHeight!=0 && bestWidth!=0)
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{
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Log.v("snap shot","Using "+bestWidth+"*"+ bestHeight);
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parameters.setPreviewSize(bestWidth,bestHeight);
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cameraView.setLayoutParams(new LinearLayout.LayoutParams(bestWidth,bestHeight));
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}
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}
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camera.setParameters(parameters);
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}
文章来源: panda1234lee.blog.csdn.net，作者：panda1234lee，版权归原作者所有，如需转载，请联系作者。
原文链接：panda1234lee.blog.csdn.net/article/details/8711095
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