Pick image from sd card, resize the image and save it back to sd card

Question

I am working on an application, in which I need to pick an image from sd card and show it in image view. Now I want the user to decrease/increase its width by c

Answer 1

Try using this method:

public static Bitmap scaleBitmap(Bitmap bitmapToScale, float newWidth, float newHeight) {   
if(bitmapToScale == null)
    return null;
//get the original width and height
int width = bitmapToScale.getWidth();
int height = bitmapToScale.getHeight();
// create a matrix for the manipulation
Matrix matrix = new Matrix();

// resize the bit map
matrix.postScale(newWidth / width, newHeight / height);

// recreate the new Bitmap and set it back
return Bitmap.createBitmap(bitmapToScale, 0, 0, bitmapToScale.getWidth(), bitmapToScale.getHeight(), matrix, true);  
} 

Answer 2

Solution without OutOfMemoryException in Kotlin

fun resizeImage(file: File, scaleTo: Int = 1024) {
    val bmOptions = BitmapFactory.Options()
    bmOptions.inJustDecodeBounds = true
    BitmapFactory.decodeFile(file.absolutePath, bmOptions)
    val photoW = bmOptions.outWidth
    val photoH = bmOptions.outHeight

    // Determine how much to scale down the image
    val scaleFactor = Math.min(photoW / scaleTo, photoH / scaleTo)

    bmOptions.inJustDecodeBounds = false
    bmOptions.inSampleSize = scaleFactor

    val resized = BitmapFactory.decodeFile(file.absolutePath, bmOptions) ?: return
    file.outputStream().use {
        resized.compress(Bitmap.CompressFormat.JPEG, 75, it)
        resized.recycle()
    }
}

Answer 3

You can use Bitmap.createScaledBitmap (Bitmap src, int dstWidth, int dstHeight, boolean filter)

Answer 4

Just yesterday i have done this

File dir=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
Bitmap b= BitmapFactory.decodeFile(PATH_ORIGINAL_IMAGE);
Bitmap out = Bitmap.createScaledBitmap(b, 320, 480, false);

File file = new File(dir, "resize.png");
FileOutputStream fOut;
try {
    fOut = new FileOutputStream(file);
    out.compress(Bitmap.CompressFormat.PNG, 100, fOut);
    fOut.flush();
    fOut.close();
    b.recycle();
    out.recycle();               
} catch (Exception e) {}

Also don't forget to recycle your bitmaps: It will save memory.

You can also get path of new created file String: newPath=file.getAbsolutePath();

Answer 5

I found this useful library for this achievement: https://github.com/hkk595/Resizer

Answer 6

You should ideally use multitouch instead of using a button to increase/decrease width. Here's an amazing library. Once the user decides to save the image, the image translation matrix must be stored persistently (in your sqlite database). Next time the user opens the image, you need to recall the matrix and apply it to your image.

I've actually done this before.