如何在安卓系统中旋转位图？

android java bitmap

2022-09-04 01:18:39

我知道这个问题已经有线程了，但解决方案似乎使用了Matrix类中的方法，这些方法似乎不再起作用。即使在导入后，也无法解析这些方法。我基本上试图将位图旋转90度，因为当我垂直拍摄照片时，它会侧向显示。以下是我的活动代码：

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.camera);
        this.imageView = (ImageView)this.findViewById(R.id.imageView1);
        Button photoButton = (Button) this.findViewById(R.id.button1);
        photoButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                File file = new File(Environment.getExternalStorageDirectory()+File.separator + "image.jpg");
                intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
                startActivityForResult(intent, CAPTURE_IMAGE_FULLSIZE_ACTIVITY_REQUEST_CODE);

            }
        });
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        //Check that request code matches ours:
        if (requestCode == CAPTURE_IMAGE_FULLSIZE_ACTIVITY_REQUEST_CODE)
        {
            //Get our saved file into a bitmap object:
            File file = new File(Environment.getExternalStorageDirectory()+File.separator + "image.jpg");
            Bitmap bitmap = decodeSampledBitmapFromFile(file.getAbsolutePath(), 1000, 700);

            Intent intent = new Intent(this, EditActivity.class);

            ByteArrayOutputStream bs = new ByteArrayOutputStream();

            bitmap.compress(Bitmap.CompressFormat.PNG, 50, bs);
            intent.putExtra("byteArray", bs.toByteArray());

            startActivity(intent);



        }
    }

答案 1

试试这个：

public static Bitmap RotateBitmap(Bitmap source, float angle)
{
      Matrix matrix = new Matrix();
      matrix.postRotate(angle);
      return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, true);
}

在这里，请传递您的位图或角度，您想要显示的位图，如90 180 etc.it 将使用类矩阵的postRotate（）方法更改位图屏幕，并再次创建位图并恢复您

答案 2

这是旋转位图的正确方法:D

public Bitmap rotateBitmap(Bitmap original, float degrees) {
        Matrix matrix = new Matrix();
        matrix.preRotate(degrees);
        Bitmap rotatedBitmap = Bitmap.createBitmap(original, 0, 0, original.getWidth(), original.getHeight(), matrix, true);
        original.recycle();
        return rotatedBitmap;
    }