Question

我需要启用用户拍照并将其保存在本地文件夹中。我这样做，但图像尺寸太大。稍后我将需要在服务器上上传该图像，我想知道优化它的最佳方法是什么。目前的图像尺寸不低于3MB

这是拍摄照片的代码：

public void takePicture() {
    Intent imageIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());

    File imagesFolder = new File(Environment.getExternalStorageDirectory(), "MyScore");

    File image = new File(imagesFolder, "QR_" + timeStamp + ".jpg");
    Uri uriSavedImage = Uri.fromFile(image);
    imageIntent.putExtra(MediaStore.EXTRA_OUTPUT, uriSavedImage);
    startActivityForResult(imageIntent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
}

我应该在这做什么魔术

 @Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
}

压缩图片

Answer 1

您可以通过此代码复制图片

public String compressImage(String filePath) {
    Bitmap scaledBitmap = null;

    BitmapFactory.Options options = new BitmapFactory.Options();

    // by setting this field as true, the actual bitmap pixels are not
    // loaded in the memory. Just the bounds are loaded. If
    // you try the use the bitmap here, you will get null.
    options.inJustDecodeBounds = true;
    Bitmap bmp = BitmapFactory.decodeFile(filePath, options);

    int actualHeight = options.outHeight;
    int actualWidth = options.outWidth;

    // max Height and width values of the compressed image is taken as
    // 800x1000

    float maxWidth = 1600.0f;
    float maxHeight = 2000.0f;
    float imgRatio = actualWidth / actualHeight;
    float maxRatio = maxWidth / maxHeight;

    // width and height values are set maintaining the aspect ratio of the
    // image

    if (actualHeight > maxHeight || actualWidth > maxWidth) {
        if (imgRatio < maxRatio) {
            imgRatio = maxHeight / actualHeight;
            actualWidth = (int) (imgRatio * actualWidth);
            actualHeight = (int) maxHeight;
        } else if (imgRatio > maxRatio) {
            imgRatio = maxWidth / actualWidth;
            actualHeight = (int) (imgRatio * actualHeight);
            actualWidth = (int) maxWidth;
        } else {
            actualHeight = (int) maxHeight;
            actualWidth = (int) maxWidth;

        }
    }

    // setting inSampleSize value allows to load a scaled down version of
    // the original image

    options.inSampleSize = calculateInSampleSize(options, actualWidth,
            actualHeight);

    // inJustDecodeBounds set to false to load the actual bitmap
    options.inJustDecodeBounds = false;

    // this options allow android to claim the bitmap memory if it runs low
    // on memory
    options.inPurgeable = true;
    options.inInputShareable = true;
    options.inTempStorage = new byte[16 * 1024];

    try {
        // load the bitmap from its path
        bmp = BitmapFactory.decodeFile(filePath, options);
    } catch (OutOfMemoryError exception) {
        exception.printStackTrace();

    }
    try {
        scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight,
                Bitmap.Config.ARGB_8888);
    } catch (OutOfMemoryError exception) {
        exception.printStackTrace();
    }

    float ratioX = actualWidth / (float) options.outWidth;
    float ratioY = actualHeight / (float) options.outHeight;
    float middleX = actualWidth / 2.0f;
    float middleY = actualHeight / 2.0f;

    Matrix scaleMatrix = new Matrix();
    scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);

    Canvas canvas = new Canvas(scaledBitmap);
    canvas.setMatrix(scaleMatrix);
    canvas.drawBitmap(bmp, middleX - bmp.getWidth() / 2,
            middleY - bmp.getHeight() / 2, new Paint(
                    Paint.FILTER_BITMAP_FLAG));

    // check the rotation of the image and display it properly
    ExifInterface exif;
    try {
        exif = new ExifInterface(filePath);

        int orientation = exif.getAttributeInt(
                ExifInterface.TAG_ORIENTATION, 0);
        //Log.d("EXIF", "Exif: " + orientation);
        Matrix matrix = new Matrix();
        if (orientation == 6) {
            matrix.postRotate(90);
            //Log.d("EXIF", "Exif: " + orientation);
        } else if (orientation == 3) {
            matrix.postRotate(180);
            //Log.d("EXIF", "Exif: " + orientation);
        } else if (orientation == 8) {
            matrix.postRotate(270);
            //Log.d("EXIF", "Exif: " + orientation);
        }
        scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0,
                scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix,
                true);
    } catch (IOException e) {
        e.printStackTrace();
    }

    FileOutputStream out = null;
    String filename = getFilename();
    try {
        out = new FileOutputStream(filename);

        // write the compressed bitmap at the destination specified by
        // filename.
        scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

    return filename;

}

从相机调整图像大小并将其存储在卡上

1 个答案: