java - 将位图旋转 90 度并保存

Question

全部！我对这个问题完全不知所措。它可能已被回答，但我找不到任何人确切地要求我需要什么。

我有一个 jpeg 文件保存到 SDCARD，并希望以编程方式将其顺时针旋转 90 度，然后将其保存回卡中（覆盖原件或在编辑后删除原件）。JPEG被加载到

File myFile;

谁能告诉我如何去做？我想它与 BitmapFactory 和矩阵有关，但就像我说的：我有点过头了！

谢谢！

Answer 1

尝试这个。

public Bitmap rotate(String file)
{
         Bitmap source = BitmapFactory.decodeFile("/sdcard/ChuckNorris.png");
         Bitmap b = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Config.ARGB_8888);

         Paint p = new Paint();
         p.setColor(Color.BLACK);

         Canvas f = new Canvas(b);
         f.drawBitmap(source, 0, 0, p);

         f.rotate(90);

         return b;
}

注意：不要自己尝试

Answer 2

I found the answer!

For JPG files, apparently you can just niftily edit the exif data using the following method:

ExifInterface exif = new ExifInterface(myFile.getAbsolutePath());
exif.setAttribute(ExifInterface.TAG_ORIENTATION, "6");
exif.saveAttributes();

Are there any downsides to using this approach? It seems to work pretty well as far as I can determine..