android - 用于旋转相机 Intent 捕获的图像的代码在 Android 中不起作用

Question

我有一个问题，我使用相机 Intent 捕获的图像被旋转了，我在 Why does an image captured using camera intent gets rotated on some devices on Android? 询问过这个问题

因此，根据那里的建议答案，我现在正在尝试旋转使用相机获得的图像(我使用了相机 Intent )。我的代码是，

public class SimpleCameraActivity extends Activity {
private static final int TAKE_PICTURE = 1888;
private Uri imageUri;
ImageView imageView;
Bitmap bitmap;
Button btnOK, btnDiscard;
RelativeLayout rLButtons;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.simple_camera);
    imageView = (ImageView) findViewById(R.id.image_view_sc);
    captureImage();
}

public void captureImage() {
    Intent intentCamera = new Intent("android.media.action.IMAGE_CAPTURE");
    File filePhoto = new File(Environment.getExternalStorageDirectory(), "Pic.jpg");
    imageUri = Uri.fromFile(filePhoto);
    MyApplicationGlobal.imageUri = imageUri.getPath();
    intentCamera.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
    startActivityForResult(intentCamera, TAKE_PICTURE);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intentFromCamera) {
    super.onActivityResult(requestCode, resultCode, intentFromCamera);
    if (resultCode == RESULT_OK && requestCode == TAKE_PICTURE) {
        if (intentFromCamera != null) {
            Bundle extras = intentFromCamera.getExtras();
            if (extras.containsKey("data")) {
                bitmap = (Bitmap) extras.get("data");
            } else {
                bitmap = getBitmapFromUri();
            }
        } else {
            bitmap = getBitmapFromUri();
        }
        checkForRotation();
        //rotateImage();
        //rotateImage1();
        rotateImage3();
        //imageView.setImageBitmap(bitmap);
        // imageView.setImageURI(imageUri);
    } else {
        finish();
    }
}

public void rotateImage() {
    Bitmap targetBitmap = Bitmap.createBitmap(100, 80, bitmap.getConfig());
    Canvas canvas = new Canvas(targetBitmap);
    Matrix matrix = new Matrix();
    matrix.setRotate(180, bitmap.getWidth() / 2, bitmap.getHeight() / 2);
    matrix.setRotate(90);
    canvas.drawBitmap(bitmap, matrix, new Paint());
    imageView.setImageBitmap(bitmap);
}

public void rotateImage1() {
    Matrix matrix = new Matrix();
    matrix.setRotate(90, bitmap.getWidth() / 2, bitmap.getHeight() / 2);
    RectF rectF = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight());
    matrix.mapRect(rectF);
    Bitmap targetBitmap = Bitmap.createBitmap((int) rectF.width(), (int) rectF.height(), bitmap.getConfig());
    Canvas canvas = new Canvas(targetBitmap);
    canvas.drawBitmap(bitmap, matrix, new Paint());
    imageView.setImageBitmap(bitmap);
}

public void rotateImage2() {
    Matrix mtx = new Matrix();
    mtx.reset();
    mtx.preTranslate(20, 30);
    mtx.setRotate((float) 90, 25, 35);
    mtx.postTranslate(30, 40);
    Bitmap rotatedBMP = Bitmap.createBitmap(bitmap, 0, 0, 100, 100, mtx, true);
    this.bitmap = rotatedBMP;
    imageView.setImageBitmap(bitmap);
}

public void rotateImage3() {
    Bitmap bmpOriginal = bitmap;
    Bitmap targetBitmap = Bitmap.createBitmap((bmpOriginal.getWidth()), (bmpOriginal.getHeight()), Bitmap.Config.ARGB_8888);
    Paint p = new Paint();
    p.setAntiAlias(true);

    Matrix matrix = new Matrix();
    matrix.setRotate((float) 90, (float) (bmpOriginal.getWidth() / 2), (float) (bmpOriginal.getHeight() / 2));

    RectF rectF = new RectF(0, 0, bmpOriginal.getWidth(), bmpOriginal.getHeight());
    matrix.mapRect(rectF);

    targetBitmap = Bitmap.createBitmap((int) rectF.width(), (int) rectF.height(), Bitmap.Config.ALPHA_8);

    Canvas tempCanvas = new Canvas(targetBitmap);
    tempCanvas.drawBitmap(bmpOriginal, matrix, p);
    imageView.setImageBitmap(bmpOriginal);
}

public Bitmap getBitmapFromUri() {
    getContentResolver().notifyChange(imageUri, null);
    ContentResolver cr = getContentResolver();
    Bitmap bitmap;
    try {
        bitmap = android.provider.MediaStore.Images.Media.getBitmap(cr, imageUri);
        return bitmap;
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
}
}

我已经尝试了不同的代码 rotateImage、1、2、3 等。但是没有代码起作用。 rotateImage2() 正在运行，但它会严重影响质量，因此不能使用它。

我从 Android: How to rotate a bitmap on a center point 得到了这些代码那里的用户说它有效，但不适用于我。 那我做错了什么。

Answer 1

坚持使用 rotateImage2() 并使用较少的转换。这段代码对我有用:

private Bitmap rotateImage(String pathToImage) {

    // 1. figure out the amount of degrees
    int rotation = getImageRotation();

    // 2. rotate matrix by postconcatination
    Matrix matrix = new Matrix();
    matrix.postRotate(rotation);

    // 3. create Bitmap from rotated matrix
    Bitmap sourceBitmap = BitmapFactory.decodeFile(pathToImage);
    return Bitmap.createBitmap(sourceBitmap, 0, 0, sourceBitmap.getWidth(), sourceBitmap.getHeight(), matrix, true);        
}

获取图像旋转check out your other post .有关矩阵运算及其差异的更多信息，例如 setRotate 和 postRotate check out this post .