[android] 서버에 업로드하기 전에 이미지 파일 크기를 줄이는 방법

Question 1

많은 응용 프로그램을 사용하여 갤러리에서 선택한 이미지를 공유 할 수 있습니다.

원본 이미지 파일을 업로드합니까? 1-3MB와 같은 것은 무엇입니까? 아니면 처리합니까?

어쨌든 파일 경로에서 이미지를 가져 와서 해상도를 낮추어 크기를 줄이고 다른 곳에 저장하고 업로드를 시도하려면 어떻게해야합니까?

나는 시도했다 :

Bitmap photo = decodeSampledBitmapFromFile(filePath, DESIRED_WIDTH,
                    DESIRED_HEIGHT);

FileOutputStream out = new FileOutputStream(filePath);
photo.compress(Bitmap.CompressFormat.JPEG, 100, out);

public static Bitmap decodeSampledBitmapFromFile(String path, int reqWidth,
        int reqHeight) {

    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(path, options);

    final int height = options.outHeight;
    final int width = options.outWidth;
    options.inPreferredConfig = Bitmap.Config.ARGB_8888;
    int inSampleSize = 1;

    if (height > reqHeight) {
        inSampleSize = Math.round((float) height / (float) reqHeight);
    }
    int expectedWidth = width / inSampleSize;

    if (expectedWidth > reqWidth) {
        inSampleSize = Math.round((float) width / (float) reqWidth);
    }
    options.inSampleSize = inSampleSize;
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeFile(path, options);
}

그러나 이것이 올바른 방법입니까? 여기에서 제안하는 답변을 보았 기 때문에compression operation takes rather big amount of time

Question 2

이 함수를 사용하여 이미지를 업로드하기 전에 이미지 크기를 줄입니다. 이미지 크기를 거의 200KB로 줄이고 품질을 비교적 양호하게 유지합니다. REQUIRED_SIZE 및 inSampleSize를 변경하여 목적에 맞게 수정할 수 있습니다.

public File saveBitmapToFile(File file){
    try {

        // BitmapFactory options to downsize the image
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        o.inSampleSize = 6;
        // factor of downsizing the image

        FileInputStream inputStream = new FileInputStream(file);
        //Bitmap selectedBitmap = null;
        BitmapFactory.decodeStream(inputStream, null, o);
        inputStream.close();

        // The new size we want to scale to
        final int REQUIRED_SIZE=75;

        // Find the correct scale value. It should be the power of 2.
        int scale = 1;
        while(o.outWidth / scale / 2 >= REQUIRED_SIZE &&
                        o.outHeight / scale / 2 >= REQUIRED_SIZE) {
            scale *= 2;
        }

        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        inputStream = new FileInputStream(file);

        Bitmap selectedBitmap = BitmapFactory.decodeStream(inputStream, null, o2);
        inputStream.close();

        // here i override the original image file
        file.createNewFile();
        FileOutputStream outputStream = new FileOutputStream(file);

        selectedBitmap.compress(Bitmap.CompressFormat.JPEG, 100 , outputStream);

        return file;
    } catch (Exception e) {
        return null;
    }
}

참고 : 이 기능에서 원본 파일 이미지의 크기를 조정하고 재정의합니다. 다른 파일에도 쓸 수 있습니다.

도움이되기를 바랍니다.

Question 3

이것은 잘 작동합니다.

private String decodeFile(String path,int DESIREDWIDTH, int DESIREDHEIGHT) {
        String strMyImagePath = null;
        Bitmap scaledBitmap = null;

        try {
            // Part 1: Decode image
            Bitmap unscaledBitmap = ScalingUtilities.decodeFile(path, DESIREDWIDTH, DESIREDHEIGHT, ScalingLogic.FIT);

            if (!(unscaledBitmap.getWidth() <= DESIREDWIDTH && unscaledBitmap.getHeight() <= DESIREDHEIGHT)) {
                // Part 2: Scale image
                scaledBitmap = ScalingUtilities.createScaledBitmap(unscaledBitmap, DESIREDWIDTH, DESIREDHEIGHT, ScalingLogic.FIT);
            } else {
                unscaledBitmap.recycle();
                return path;
            }

            // Store to tmp file

            String extr = Environment.getExternalStorageDirectory().toString();
            File mFolder = new File(extr + "/TMMFOLDER");
            if (!mFolder.exists()) {
                mFolder.mkdir();
            }

            String s = "tmp.png";

            File f = new File(mFolder.getAbsolutePath(), s);

            strMyImagePath = f.getAbsolutePath();
            FileOutputStream fos = null;
            try {
                fos = new FileOutputStream(f);
                scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 75, fos);
                fos.flush();
                fos.close();
            } catch (FileNotFoundException e) {

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

                e.printStackTrace();
            }

            scaledBitmap.recycle();
        } catch (Throwable e) {
        }

        if (strMyImagePath == null) {
            return path;
        }
        return strMyImagePath;

    }

ScalingUtilities.java

import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.BitmapFactory.Options;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;

/**
 * Class containing static utility methods for bitmap decoding and scaling
 *
 * @author
 */
public class ScalingUtilities {

    /**
     * Utility function for decoding an image resource. The decoded bitmap will
     * be optimized for further scaling to the requested destination dimensions
     * and scaling logic.
     *
     * @param res The resources object containing the image data
     * @param resId The resource id of the image data
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Decoded bitmap
     */
    public static Bitmap decodeResource(Resources res, int resId, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        Options options = new Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(res, resId, options);
        options.inJustDecodeBounds = false;
        options.inSampleSize = calculateSampleSize(options.outWidth, options.outHeight, dstWidth,
                dstHeight, scalingLogic);
        Bitmap unscaledBitmap = BitmapFactory.decodeResource(res, resId, options);

        return unscaledBitmap;
    }
    public static Bitmap decodeFile(String path, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        Options options = new Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(path, options);
        options.inJustDecodeBounds = false;
        options.inSampleSize = calculateSampleSize(options.outWidth, options.outHeight, dstWidth,
                dstHeight, scalingLogic);
        Bitmap unscaledBitmap = BitmapFactory.decodeFile(path, options);

        return unscaledBitmap;
    }

    /**
     * Utility function for creating a scaled version of an existing bitmap
     *
     * @param unscaledBitmap Bitmap to scale
     * @param dstWidth Wanted width of destination bitmap
     * @param dstHeight Wanted height of destination bitmap
     * @param scalingLogic Logic to use to avoid image stretching
     * @return New scaled bitmap object
     */
    public static Bitmap createScaledBitmap(Bitmap unscaledBitmap, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        Rect srcRect = calculateSrcRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(),
                dstWidth, dstHeight, scalingLogic);
        Rect dstRect = calculateDstRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(),
                dstWidth, dstHeight, scalingLogic);
        Bitmap scaledBitmap = Bitmap.createBitmap(dstRect.width(), dstRect.height(),
                Config.ARGB_8888);
        Canvas canvas = new Canvas(scaledBitmap);
        canvas.drawBitmap(unscaledBitmap, srcRect, dstRect, new Paint(Paint.FILTER_BITMAP_FLAG));

        return scaledBitmap;
    }

    /**
     * ScalingLogic defines how scaling should be carried out if source and
     * destination image has different aspect ratio.
     *
     * CROP: Scales the image the minimum amount while making sure that at least
     * one of the two dimensions fit inside the requested destination area.
     * Parts of the source image will be cropped to realize this.
     *
     * FIT: Scales the image the minimum amount while making sure both
     * dimensions fit inside the requested destination area. The resulting
     * destination dimensions might be adjusted to a smaller size than
     * requested.
     */
    public static enum ScalingLogic {
        CROP, FIT
    }

    /**
     * Calculate optimal down-sampling factor given the dimensions of a source
     * image, the dimensions of a destination area and a scaling logic.
     *
     * @param srcWidth Width of source image
     * @param srcHeight Height of source image
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Optimal down scaling sample size for decoding
     */
    public static int calculateSampleSize(int srcWidth, int srcHeight, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        if (scalingLogic == ScalingLogic.FIT) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                return srcWidth / dstWidth;
            } else {
                return srcHeight / dstHeight;
            }
        } else {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                return srcHeight / dstHeight;
            } else {
                return srcWidth / dstWidth;
            }
        }
    }

    /**
     * Calculates source rectangle for scaling bitmap
     *
     * @param srcWidth Width of source image
     * @param srcHeight Height of source image
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Optimal source rectangle
     */
    public static Rect calculateSrcRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        if (scalingLogic == ScalingLogic.CROP) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                final int srcRectWidth = (int)(srcHeight * dstAspect);
                final int srcRectLeft = (srcWidth - srcRectWidth) / 2;
                return new Rect(srcRectLeft, 0, srcRectLeft + srcRectWidth, srcHeight);
            } else {
                final int srcRectHeight = (int)(srcWidth / dstAspect);
                final int scrRectTop = (int)(srcHeight - srcRectHeight) / 2;
                return new Rect(0, scrRectTop, srcWidth, scrRectTop + srcRectHeight);
            }
        } else {
            return new Rect(0, 0, srcWidth, srcHeight);
        }
    }

    /**
     * Calculates destination rectangle for scaling bitmap
     *
     * @param srcWidth Width of source image
     * @param srcHeight Height of source image
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Optimal destination rectangle
     */
    public static Rect calculateDstRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        if (scalingLogic == ScalingLogic.FIT) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                return new Rect(0, 0, dstWidth, (int)(dstWidth / srcAspect));
            } else {
                return new Rect(0, 0, (int)(dstHeight * srcAspect), dstHeight);
            }
        } else {
            return new Rect(0, 0, dstWidth, dstHeight);
        }
    }

}

Question 4

이 코드는 이미지 크기를 줄입니다.

private Bitmap compressImage(Bitmap image) {

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        image.compress(Bitmap.CompressFormat.JPEG, 100, baos);//Compression quality, here 100 means no compression, the storage of compressed data to baos
        int options = 90;
        while (baos.toByteArray().length / 1024 > 400) {  //Loop if compressed picture is greater than 400kb, than to compression
            baos.reset();//Reset baos is empty baos
            image.compress(Bitmap.CompressFormat.JPEG, options, baos);//The compression options%, storing the compressed data to the baos
            options -= 10;//Every time reduced by 10
        }
        ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//The storage of compressed data in the baos to ByteArrayInputStream
        Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);//The ByteArrayInputStream data generation
        return bitmap;
    }

Question 5

다음은 메모리에서 처리되고 실제로 파일 시스템에서 파일을 생성 할 필요가없는 솔루션입니다.

일부 Fragment에서 사용자가 이미지 파일을 선택한 후 :

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

    if (imageReturnedIntent == null
            || imageReturnedIntent.getData() == null) {
        return;
    }

    // aiming for ~500kb max. assumes typical device image size is around 2megs
    int scaleDivider = 4;


    try {

        // 1. Convert uri to bitmap
        Uri imageUri = imageReturnedIntent.getData();
        Bitmap fullBitmap = MediaStore.Images.Media.getBitmap(getActivity().getContentResolver(), imageUri);

        // 2. Get the downsized image content as a byte[]
        int scaleWidth = fullBitmap.getWidth() / scaleDivider;
        int scaleHeight = fullBitmap.getHeight() / scaleDivider;
        byte[] downsizedImageBytes =
                getDownsizedImageBytes(fullBitmap, scaleWidth, scaleHeight);

        // 3. Upload the byte[]; Eg, if you are using Firebase
        StorageReference storageReference =
                FirebaseStorage.getInstance().getReference("/somepath");

        storageReference.putBytes(downsizedImageBytes);
    }
    catch (IOException ioEx) {
        ioEx.printStackTrace();
    }
}

public byte[] getDownsizedImageBytes(Bitmap fullBitmap, int scaleWidth, int scaleHeight) throws IOException {

    Bitmap scaledBitmap = Bitmap.createScaledBitmap(fullBitmap, scaleWidth, scaleHeight, true);

    // 2. Instantiate the downsized image content as a byte[]
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
    byte[] downsizedImageBytes = baos.toByteArray();

    return downsizedImageBytes;
}

덕분에 :

URI를 비트 맵으로 변환 : https://stackoverflow.com/a/4717740/2162226
확장 / 크기 조정 단계 (이 스레드에서) : https://stackoverflow.com/a/50192169/2162226
Firebase에 byte [] 저장 : https://stackoverflow.com/a/40886397/2162226

Question 6

여기 내 해결책이 있습니다.

/*
* This procedure will replace the original image
* So you need to do a tmp copy to send before reduce
*/
public static boolean reduceImage(String path, long maxSize) {
    File img = new File(path);
    boolean result = false;
    BitmapFactory.Options options = new BitmapFactory.Options();
    Bitmap bitmap = null;
    options.inSampleSize=1;
    while (img.length()>maxSize) {
        options.inSampleSize = options.inSampleSize+1;
        bitmap = BitmapFactory.decodeFile(path, options);
        img.delete();
        try
            {
                FileOutputStream fos = new FileOutputStream(path);
                img.compress(path.toLowerCase().endsWith("png")?
                                Bitmap.CompressFormat.PNG:
                                Bitmap.CompressFormat.JPEG, 100, fos);
                fos.close();
                result = true;
             }catch (Exception errVar) {
                errVar.printStackTrace();
             }
    };
    return result;
}

편집 제거 된 다른 프로 시저 호출

Question 7

다음은 kotlin 에서 사용하는 iam 메소드입니다. .

참고 : 3 개의 이미지로 시도해 보았습니다. 각각 6MB 이고 한 번의 호출로

 private fun Bitmap.compress(cacheDir: File, f_name: String): File? {
    val f = File(cacheDir, "user$f_name.jpg")
    f.createNewFile()
    ByteArrayOutputStream().use { stream ->
        compress(Bitmap.CompressFormat.JPEG, 70, stream)
        val bArray = stream.toByteArray()
        FileOutputStream(f).use { os -> os.write(bArray) }
    }//stream
    return f
}

Question 8

약 200KB로 압축 된 비트 맵 이미지를 반환하는이 메서드를 사용합니다. 원하는 크기의 비트 맵 이미지를 얻도록 구성 할 수 있습니다.

public static Bitmap scaleImage(Context context, Uri photoUri) throws IOException {
    InputStream is = context.getContentResolver().openInputStream(photoUri);
    BitmapFactory.Options dbo = new BitmapFactory.Options();
    dbo.inJustDecodeBounds = true;
    BitmapFactory.decodeStream(is, null, dbo);
    is.close();

    int rotatedWidth, rotatedHeight;
    int orientation = getOrientation(context, photoUri);

    if (orientation == 90 || orientation == 270) {
        rotatedWidth = dbo.outHeight;
        rotatedHeight = dbo.outWidth;
    } else {
        rotatedWidth = dbo.outWidth;
        rotatedHeight = dbo.outHeight;
    }

    Bitmap srcBitmap;
    is = context.getContentResolver().openInputStream(photoUri);
    if (rotatedWidth > MAX_IMAGE_DIMENSION || rotatedHeight > MAX_IMAGE_DIMENSION) {
        float widthRatio = ((float) rotatedWidth) / ((float) MAX_IMAGE_DIMENSION);
        float heightRatio = ((float) rotatedHeight) / ((float) MAX_IMAGE_DIMENSION);
        float maxRatio = Math.max(widthRatio, heightRatio);

        // Create the bitmap from file
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inSampleSize = (int) maxRatio;
        srcBitmap = BitmapFactory.decodeStream(is, null, options);
    } else {
        srcBitmap = BitmapFactory.decodeStream(is);
    }
    is.close();

    /*
     * if the orientation is not 0 (or -1, which means we don't know), we
     * have to do a rotation.
     */
    if (orientation > 0) {
        Matrix matrix = new Matrix();
        matrix.postRotate(orientation);

        srcBitmap = Bitmap.createBitmap(srcBitmap, 0, 0, srcBitmap.getWidth(),
                srcBitmap.getHeight(), matrix, true);
    }

    String type = context.getContentResolver().getType(photoUri);
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    if (type.equals("image/png")) {
        srcBitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
    } else if (type.equals("image/jpg") || type.equals("image/jpeg")) {
        srcBitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
    }
    byte[] bMapArray = baos.toByteArray();
    baos.close();
    return BitmapFactory.decodeByteArray(bMapArray, 0, bMapArray.length);
}