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[英]How to convert .raw file to image file in android rooted device programmatically
[英]NullPointerException when convert and save Image file on Android device
我正在尝试将图像类型数据作为jpg文件保存到SD卡,我打算先将其转换为位图,将位图压缩为jpeg格式,然后使用FileOutputStream将其保存到SD卡。
这是我的代码:
File imagefile = new File(sdCardPath, "image.jpg");
Image image = fromFrame.getImage();
ByteBuffer bbuffer = image.getPlanes()[0].getBuffer();
byte[] byts = new byte[bbuffer.capacity()];
bbuffer.get(byts);
Bitmap bitmapImage = BitmapFactory.decodeByteArray(byts, 0, byts.length, null);
try{
FileOutputStream out = new FileOutputStream(imagefile);
bitmapImage.compress(Bitmap.CompressFormat.JPEG, 100, out);
out.flush();
out.close();
} catch (FileNotFoundException e) {
Log.v(TAG, "FileNotFoundExceptionError " + e.toString());
} catch (IOException e) {
Log.v(TAG, "IOExceptionError " + e.toString());
}
它给出了错误:
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean
android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat,
int, java.io.OutputStream)' on a null object reference
有什么我错过或做错了吗?
原来图像文件必须重新组织,而对于 Depth16 文件,每个像素都有 16 位数据,因此将其转换为 jpg 文件的代码是:
Image depthimage = fromFrame.getImage();
int imwidth = depthImage.getWidth();
int imheight = depthImage.getHeight();
Image.Plane plane = depthImage.getPlanes()[0];
ShortBuffer shortDepthBuffer = plane.getBuffer().asShortBuffer();
File sdCardFile = Environment.getExternalStorageDirectory();
File file = new File(sdCardFile, "depthImage.jpg");
Bitmap disBitmap = Bitmap.createBitmap(imwidth, imheight, Bitmap.Config.RGB_565);
for (int i = 0; i < imheight; i++) {
for (int j = 0; j < imwidth; j++) {
int index = (i * imwidth + j) ;
shortDepthBuffer.position(index);
short depthSample = shortDepthBuffer.get();
short depthRange = (short) (depthSample & 0x1FFF);
byte value = (byte) depthRange ;
disBitmap.setPixel(j, i, Color.rgb(value, value, value));
}
}
Matrix matrix = new Matrix();
matrix.setRotate(90);
Bitmap rotatedBitmap = Bitmap.createBitmap(disBitmap, 0, 0, imwidth, imheight, matrix, true);
try {
FileOutputStream out = new FileOutputStream(file);
rotatedBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
MainActivity.num++;
} catch (Exception e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
我还旋转了图片,以便在移动设备上更容易查看
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