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回答
这几天看到亚瑟boy的技术连载，也试着做了下带滤镜特效的照相机，效果也出来了，但是发现添加滤镜特效后的预览窗口卡屏现象很严重，于是自己索性试着尝试修改，在亚瑟和其他网友的代码中基本上都是对于照相机data视频流先进行解码，然后对解码出的帧Bitmap进行滤镜算法处理，这个是必走的流程，而每一帧在处理解码和滤镜时都需要用掉大量时间，我测了下，解码需要300毫秒左右，滤镜处理需要600毫秒左右（冰冻滤镜），如此一来，处理完这两个流程需要的时间要在900毫秒甚至更长，我们知道如果看上去比较流畅的话我们需要每秒更新三帧的图片，而这么处理只能更新一张，明显的卡屏。
于是试着去缩小处理的Bitmap大小，在照相机预览返回照片大小中设置：
Camera.Parameters parameters =
camera.getParameters();parameters.setPreviewSize(display.getWidth()/2, display.getHeight()/2);
//
设置预览照片的大小
原来默认是返回屏幕大小的预览图片，此时我改成了屏幕大小一半的图片，发现处理过程明显加快了（当然也有稍微的卡屏），最后在预览回调接口PreviewCallBack中再将图片放大到屏幕大小，有雨我预览图片返回时只是缩小了一半，此时放大回屏幕大小时仍然是非常清晰的，如果你想速度更快的话可以继续缩小预览图片的返回大小。
代码如下：
public
class CameraActivity
extends
NoSearchActivity {
private
static
final String TAG = "CameraActivity"
;
private
SurfaceView surfaceView;
private
Camera camera;
private
boolean
view;
private
ImageButton take_picture;
private
int
width,height; @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.camera_view); ButtonClickingListener buttonlistener =
new
ButtonClickingListener(); surfaceView = (SurfaceView)
this
.findViewById(R.id.camera_surface); WindowManager wm =
(WindowManager) getSystemService(Context.WINDOW_SERVICE); Display display =
wm.getDefaultDisplay(); width =
display.getWidth(); height =
display.getHeight(); take_picture = (ImageButton) findViewById(R.id.take_picture);
//
拍照
take_picture.setOnClickListener(buttonlistener); surfaceView.getHolder().setFixedSize(width, height);
//
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().addCallback(
new
SurfaceCallback()); }
//
按钮监听
private
final
class ButtonClickingListener
implements
View.OnClickListener { @Override
public
void
onClick(View v) {
if (!
Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { Toast.makeText(CameraActivity.
this, R.string.sdcarderror, 1
).show();
return
; }
try
{
switch
(v.getId()) {
case
R.id.take_picture: camera.takePicture(
null,
null,
new
TakePictureCallback());
break
; } }
catch
(Exception e) { Toast.makeText(CameraActivity.
this, R.string.error, 1
).show(); Log.e(TAG, e.toString()); } } } @Override
protected
void
onDestroy() {
//
TODO Auto-generated method stub
if(camera!=
null
){ camera.setPreviewCallback(
null
) ; camera.stopPreview(); camera.release(); camera =
null
; }
super
.onDestroy(); }
private
final
class SurfaceCallback
implements
SurfaceHolder.Callback { @Override
public
void surfaceChanged(SurfaceHolder holder,
int format,
int width,
int
height) {} @Override
public
void
surfaceCreated(SurfaceHolder holder) {
if(camera==
null
){ camera = Camera.open();
//
打开相机 }
else
{ Toast.makeText(CameraActivity.
this, "相机正在使用中", 1
).show(); } WindowManager wm =
(WindowManager) getSystemService(Context.WINDOW_SERVICE); Display display =
wm.getDefaultDisplay(); Camera.Parameters parameters =
camera.getParameters(); parameters.setPreviewSize(display.getWidth()/2, display.getHeight()/2);
//
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", 100);
//
照片质量 parameters.setPictureSize(display.getWidth(), display.getHeight());
//
设置照片的大小
camera.setParameters(parameters); camera.setPreviewCallback(
new PreviewCallBack());
//
通过SurfaceView显示取景画面 camera.startPreview();
//
开始预览 view =
true
; } @Override
public
void
surfaceDestroyed(SurfaceHolder holder) {
if (camera !=
null
) {
if
(view) camera.stopPreview(); camera.release(); } } } @Override
public
boolean onKeyDown(
int
keyCode, KeyEvent event) {
if (camera !=
null && event.getRepeatCount() == 0
) {
switch
(keyCode) {
case
KeyEvent.KEYCODE_MENU: camera.autoFocus(
null);
//
自动对焦
break
;
case
KeyEvent.KEYCODE_CAMERA:
case
KeyEvent.KEYCODE_DPAD_CENTER: camera.takePicture(
null,
null,
new
TakePictureCallback());
break
;
case
KeyEvent.KEYCODE_BACK:
new AlertDialog.Builder(CameraActivity.
this).setTitle("提示"
) .setMessage("确定退出照相机?").setPositiveButton("确定"
,
new
DialogInterface.OnClickListener() {
public
void onClick(DialogInterface dialog,
int
whichButton) { Intent exit =
new
Intent(Intent.ACTION_MAIN); exit.addCategory(Intent.CATEGORY_HOME); exit.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(exit); System.exit(0
); } }).setNegativeButton("取消",
new
DialogInterface.OnClickListener() {
public
void onClick(DialogInterface dialog,
int
whichButton) {
//
取消按钮事件
dialog.cancel(); } }).show();
break
; } }
return
super.onKeyDown(keyCode, event);
//
不会回到 home 页面
}
//
预览回调接口
private
final
class PreviewCallBack
implements
Camera.PreviewCallback {
public
void onPreviewFrame(
byte
[] data, Camera camera) {
if (data !=
null
) {
int imageWidth =
camera.getParameters().getPreviewSize().width;
int imageHeight =
camera.getParameters().getPreviewSize().height;
int RGBData[] =
new
int[imageWidth *
imageHeight]; decodeYUV420SP(RGBData, data, imageWidth, imageHeight);
//
解码 Bitmap bm =
Bitmap.createBitmap(RGBData, imageWidth, imageHeight, Config.ARGB_8888);
//
bm = toGrayscale(bm);
//
实时滤镜效果，现在是变成黑白效果 bm = ice(bm);
//
冰冻效果 Canvas canvas =
surfaceView.getHolder().lockCanvas();
//
判断非null，才能drawBitmap.
if (bm !=
null
) { bm = Bitmap.createScaledBitmap(bm, width, height,
false
); canvas.drawBitmap(bm, 0, 0,
null
); } surfaceView.getHolder().unlockCanvasAndPost(canvas); } } }
灰度效果（黑白照片）
public
static
Bitmap toGrayscale(Bitmap bmp) {
int height =
bmp.getHeight();
int width =
bmp.getWidth(); Bitmap bmpGrayscale =
Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565); Canvas c =
new
Canvas(bmpGrayscale); Paint paint =
new
Paint(); ColorMatrix cm =
new
ColorMatrix(); cm.setSaturation(0
); ColorMatrixColorFilter f =
new
ColorMatrixColorFilter(cm); paint.setColorFilter(f); c.drawBitmap(bmp, 0, 0
, paint);
return
bmpGrayscale; }
冰冻特效
public
static
Bitmap ice(Bitmap bmp) {
int width =
bmp.getWidth();
int height =
bmp.getHeight(); Bitmap bitmap =
Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
int dst[] =
new
int[width *
height]; bmp.getPixels(dst, 0, width, 0, 0
, width, height);
int
R, G, B, pixel;
int
pos, pixColor;
for (
int y = 0; y < height; y++
) {
for (
int x = 0; x < width; x++
) { pos = y * width +
x; pixColor = dst[pos];
//
获取图片当前点的像素值 R = Color.red(pixColor);
//
获取RGB三原色 G =
Color.green(pixColor); B =
Color.blue(pixColor); pixel = R - G -
B; pixel = pixel * 3 / 2
;
if (pixel < 0 ) pixel = - pixel; if (pixel > 255 ) pixel = 255 ;
R = pixel; // 计算后重置R值，以下类同 pixel = G - B - R; pixel = pixel * 3 / 2 ;
if (pixel < 0 ) pixel = - pixel; if (pixel > 255 ) pixel = 255 ;
G = pixel; pixel = B - R - G; pixel = pixel * 3 / 2 ;
if (pixel < 0 ) pixel = - pixel; if (pixel > 255 ) pixel = 255 ; B = pixel; dst[pos] = Color.rgb(R, G, B); // 重置当前点的像素值 } // x } // y bitmap.setPixels(dst, 0, width, 0, 0 , width, height); return bitmap; }
if (pixel < 0 ) pixel = - pixel; if (pixel > 255 ) pixel = 255 ;
R = pixel; // 计算后重置R值，以下类同 pixel = G - B - R; pixel = pixel * 3 / 2 ;
if (pixel < 0 ) pixel = - pixel; if (pixel > 255 ) pixel = 255 ;
G = pixel; pixel = B - R - G; pixel = pixel * 3 / 2 ;
if (pixel < 0 ) pixel = - pixel; if (pixel > 255 ) pixel = 255 ; B = pixel; dst[pos] = Color.rgb(R, G, B); // 重置当前点的像素值 } // x } // y bitmap.setPixels(dst, 0, width, 0, 0 , width, height); return bitmap; }
获取照片回调
private
final
class TakePictureCallback
implements
PictureCallback { @Override
public
void onPictureTaken(
byte
[] data, Camera camera) {
try
{ Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0
,data.length); bitmap =
ice(bitmap); File file =
new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis() + ".jpg");
//
保存在SD卡根目录下，以当前时间毫秒命名 FileOutputStream outStream =
new
FileOutputStream(file); bitmap.comss(ComssFormat.JPEG, 100
, outStream); outStream.close(); camera.stopPreview(); camera.startPreview();
//
重新开始照相预览 }
catch
(Exception e) { Log.e(TAG, e.toString()); } } }
解码
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 ); } } } }
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 ); } } } }
camera_view 代码：
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:background="#000000"> <SurfaceView android:id="@+id/camera_surface"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:layout_weight="2.0" /> <LinearLayout android:orientation="vertical"
android:layout_width="50dip"
android:layout_height="fill_parent"
android:gravity="center_vertical"> <ImageButton android:layout_width="48dip"
android:layout_height="48dip"
android:src="@android:drawable/ic_menu_camera"
android:id="@+id/take_picture" /> <View android:layout_width="40dip"
android:layout_height="fill_parent"
android:layout_weight="2.0"/> </LinearLayout> </LinearLayout>
效果如下图：照相机冰冻效果
原文链接：http://www.cnblogs.com/vus520/archive/2012/04/12/2561976.html
