Android resize bitmap keeping aspect ratio

Zbarcea Christian picture Zbarcea Christian · Jul 25, 2014 · Viewed 39.5k times · Source

I have a custom view (1066 x 738), and I am passing a bitmap image (720x343). I want to scale the bitmap to fit in the custom view without exceeding the bound of the parent.

enter image description here

I want to achieve something like this:

enter image description here

How should I calculate the bitmap size?

How I calculate the new width/height:

    public static Bitmap getScaledBitmap(Bitmap b, int reqWidth, int reqHeight)
    {
        int bWidth = b.getWidth();
        int bHeight = b.getHeight();

        int nWidth = reqWidth;
        int nHeight = reqHeight;

        float parentRatio = (float) reqHeight / reqWidth;

        nHeight = bHeight;
        nWidth = (int) (reqWidth * parentRatio);

        return Bitmap.createScaledBitmap(b, nWidth, nHeight, true);
    }

But all I am achieving is this:

enter image description here

Answer

matiash picture matiash · Jul 25, 2014

You should try using a transformation matrix built for ScaleToFit.CENTER. For example:

Matrix m = new Matrix();
m.setRectToRect(new RectF(0, 0, b.getWidth(), b.getHeight()), new RectF(0, 0, reqWidth, reqHeight), Matrix.ScaleToFit.CENTER);
return Bitmap.createBitmap(b, 0, 0, b.getWidth(), b.getHeight(), m, true);