Camara 自定义预览效果
通过List<Integer> list = Camera.Parameters.getSupportedPreviewFormats（）；这个方法来判断手机支持哪种类型的PixelFormat，一般情况下是 NV21 即值为17. BitmapFactory.decodeByteArray这个方法是不能直接解析NV21格式的byte[]，返回的是null，所以需要对NV21格式的byte[]进行转换.
最后：sdk 2.2提供了类YuvImage 通过方法compressToJpeg进行转换，但是sdk2.1没有现成的api进行此操作（或者是说我没找到，找到了给说一下），所以需要自己进行格式的转换.
MainActivity
package cn.itcast.picture;
import java.io.File;
import java.io.FileOutputStream;
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.PixelFormat;
import android.graphics.Bitmap.CompressFormat;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Display;
import android.view.KeyEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
private SurfaceView surfaceView;
private Camera camera;
Bitmap mBitmap;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Window window = getWindow();
requestWindowFeature(Window.FEATURE_NO_TITLE);// 没有标题
window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);// 设置全屏
window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);// 高亮
setContentView(R.layout.main);
surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
surfaceView.getHolder().setFixedSize(176, 144); // 设置分辨率
/* 下面设置Surface不维护自己的缓冲区，而是等待屏幕的渲染引擎将内容推送到用户面前 */
// surfaceView.getHolder()
// .setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
surfaceView.getHolder().addCallback(new SurfaceCallback());
}
private final class SurfaceCallback implements SurfaceHolder.Callback {
private boolean preview;
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
public void surfaceCreated(SurfaceHolder holder) {
// 打开摄像头
camera = Camera.open();
WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewSize(display.getWidth(), display.getHeight());// 设置预览照片的大小
parameters.setPreviewFrameRate(3);// 每秒3帧
parameters.setPictureFormat(PixelFormat.JPEG);// 设置照片的输出格式
parameters.set("jpeg-quality", 85);// 照片质量
// parameters.setPreviewFormat(PixelFormat.JPEG);//必须底层驱动支持，设置才有效。
// parameters.setPictureSize(display.getWidth(),
// display.getHeight());// 设置照片的大小
camera.setParameters(parameters);
// try {
// camera.setPreviewDisplay(surfaceView.getHolder());//
// 通过SurfaceView显示取景画面
camera.setPreviewCallback(new PreviewCallBack());
camera.startPreview();
preview = true;
// } catch (IOException e) {
// Log.e(TAG, e.toString());
// }
}
public void surfaceDestroyed(SurfaceHolder holder) {
if (camera != null) {
if (preview) {
camera.stopPreview();
}
camera.release();
}
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (camera != null && event.getRepeatCount() == 0) {
switch (keyCode) {
case KeyEvent.KEYCODE_SEARCH:// 搜索键
// 自动对焦
camera.autoFocus(null);
return true;
case KeyEvent.KEYCODE_CAMERA:// 拍照键
case KeyEvent.KEYCODE_DPAD_CENTER:// 确定键
camera.takePicture(null, null, new TakePictureCallback());
return true;
}
}
return super.onKeyDown(keyCode, event);
}
private final class TakePictureCallback implements PictureCallback {
public void onPictureTaken(byte[] data, Camera camera) {
try {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,
data.length);
File file = new File(Environment.getExternalStorageDirectory(),
System.currentTimeMillis() + ".jpg");
FileOutputStream outStream = new FileOutputStream(file);
bitmap.compress(CompressFormat.JPEG, 100, outStream);
outStream.close();
camera.stopPreview();
camera.startPreview();
} catch (Exception e) {
Log.e(TAG, e.toString());
}
}
}
private final class PreviewCallBack implements Camera.PreviewCallback {
/*
* (non-Javadoc)
*
* @see android.hardware.Camera.PreviewCallback#onPreviewFrame(byte[],
* android.hardware.Camera)
*/
public void onPreviewFrame(byte[] data, Camera camera) {
Camera.Parameters parameters = camera.getParameters();
int format = parameters.getPreviewFormat();
List<Integer> list = parameters.getSupportedPreviewFormats();
for (Integer i : list) {
// 查看camara驱动支持的format.
// Log.e(TAG, "suport format:" + i);
}
// Log.e(TAG, "format:" + format);
if (mBitmap != null) {
mBitmap.recycle();
mBitmap = null;
}
// YUV formats require more conversion
if (format == PixelFormat.YCbCr_420_SP
|| format == PixelFormat.YCbCr_422_I) {
int w = parameters.getPreviewSize().width;
int h = parameters.getPreviewSize().height;
// Get the YuV image 由于此方法适用于android 2.2版本，所以此处不能用。
// YuvImage yuv_image = new YuvImage(data, format, w, h, null);
// // Convert YuV to Jpeg
// Rect rect = new Rect(0, 0, w, h);
// ByteArrayOutputStream output_stream = new
// ByteArrayOutputStream();
// yuv_image.compressToJpeg(rect, 100, output_stream);
// // Convert from Jpeg to Bitmap
// bitmap2 = BitmapFactory.decodeByteArray(output_stream
// .toByteArray(), 0, output_stream.size());
int[] i = new int[data.length];
decodeYUV420SP(i, data, w, h);
mBitmap = Bitmap.createBitmap(i, w, h, Bitmap.Config.RGB_565);
// mBitmap = renderCroppedGreyscaleBitmap(data, w, h);
}
// Jpeg and RGB565 are supported by BitmapFactory.decodeByteArray
else if (format == PixelFormat.JPEG
|| format == PixelFormat.RGB_565) {
mBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
}
Bitmap bitmap = BitmapFactory.decodeResource(MainActivity.this
.getResources(), R.drawable.test);
// Log.e(TAG, "mBitmap:" + mBitmap + "format:" + format);
Canvas canvas = surfaceView.getHolder().lockCanvas();
// 判断非null，才能drawBitmap.
if (mBitmap != null) {
canvas.drawBitmap(mBitmap, 0, 0, null);
}
canvas.drawBitmap(bitmap, 0, 0, null);
surfaceView.getHolder().unlockCanvasAndPost(canvas);
}
}
static public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width,
int height) {
final int frameSize = width * height;
for (int j = 0, yp = 0; j < height; j++) {
int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
for (int i = 0; i < width; i++, yp++) {
int y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
int y1192 = 1192 * y;
int r = (y1192 + 1634 * v);
int g = (y1192 - 833 * v - 400 * u);
int b = (y1192 + 2066 * u);
if (r < 0)
r = 0;
else if (r > 262143)
r = 262143;
if (g < 0)
g = 0;
else if (g > 262143)
g = 262143;
if (b < 0)
b = 0;
else if (b > 262143)
b = 262143;
rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000)
| ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
}
}
}
/**
* 此方法来源于网络，效果太差。
*
* @param yuvData
* @param width
* @param height
* @return
*/
public Bitmap renderCroppedGreyscaleBitmap(byte[] yuvData, int width,
int height) {
int[] pixels = new int[width * height];
byte[] yuv = yuvData;
int inputOffset = 0 * 320 + 40;
for (int y = 0; y < height; y++) {
int outputOffset = y * width;
for (int x = 0; x < width; x++) {
int grey = yuv[inputOffset + x] & 0xff;
pixels[outputOffset + x] = 0xFF000000 | (grey * 0x00010101);
}
inputOffset += 320;
}
Bitmap bitmap = Bitmap.createBitmap(width, height,
Bitmap.Config.ARGB_8888);
bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
return bitmap;
}
/**
* 此方法来源于网络，经验证不好用。
*
* @param rgbBuf
* @param yuv420sp
* @param width
* @param height
*/
static public void decodeYUV420SP(byte[] rgbBuf, byte[] yuv420sp,
int width, int height) {
final int frameSize = width * height;
if (rgbBuf == null)
throw new NullPointerException("buffer 'rgbBuf' is null");
if (rgbBuf.length < frameSize * 3)
throw new IllegalArgumentException("buffer 'rgbBuf' size "
+ rgbBuf.length + " < minimum "
+ frameSize * 3);
if (yuv420sp == null)
throw new NullPointerException("buffer 'yuv420sp' is null");
if (yuv420sp.length < frameSize * 3 / 2)
throw new IllegalArgumentException("buffer 'yuv420sp' size "
+ yuv420sp.length
+ " < minimum " + frameSize * 3
/ 2);
int i = 0, y = 0;
int uvp = 0, u = 0, v = 0;
int y1192 = 0, r = 0, g = 0, b = 0;
for (int j = 0, yp = 0; j < height; j++) {
uvp = frameSize + (j >> 1) * width;
u = 0;
v = 0;
for (i = 0; i < width; i++, yp++) {
y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
y1192 = 1192 * y;
r = (y1192 + 1634 * v);
g = (y1192 - 833 * v - 400 * u);
b = (y1192 + 2066 * u);
if (r < 0)
r = 0;
else if (r > 262143)
r = 262143;
if (g < 0)
g = 0;
else if (g > 262143)
g = 262143;
if (b < 0)
b = 0;
else if (b > 262143)
b = 262143;
rgbBuf[yp * 3] = (byte) (r >> 10);
rgbBuf[yp * 3 + 1] = (byte) (g >> 10);
rgbBuf[yp * 3 + 2] = (byte) (b >> 10);
}
}
}
}
转载:http://www.adobex.com/android/source/details/00000391.htm